Article

Etiologic Classification of Seizures, Signalment, Clinical Signs, and Outcome in Cats with Seizure Disorders: 91 Cases (2000–2004)

Authors:
  • Tierärztliche Fachklinik für Kleintiere, Haar, Germany
  • Ludwig-Maximilians-Universitaet Muenchen
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Abstract

To evaluate associations among etiologic classifications of seizures and signalment, clinical signs, and outcome in cats with various seizure disorders. Retrospective case series. 91 cats evaluated for seizure disorders at a veterinary teaching hospital from 2000 through 2004. Data regarding characteristics of the cats and their seizures were obtained from medical records. Seizures were classified as reactive, symptomatic, or idiopathic. Survival times were displayed as Kaplan-Meier curves, and differences between etiologic classifications were assessed by log-rank test. Over the 5-year period, the incidence of seizures among all cats evaluated at the hospital was 2.1%. Etiology was classified as reactive in 20 (22%) cats, symptomatic in 45 (50%), idiopathic or presumptive idiopathic in 23 (25%), and cardiac syncope in 3 (3%). Focal seizures with or without secondary generalization were recorded for 47 (52%) cats, and primary generalized seizures with or without status epilepticus were recorded for 44 (48%). Etiology was not associated with seizure type. However, mean age of cats with idiopathic seizures (3.5 years) was significantly lower than that of cats with reactive seizures (8.2 years) or symptomatic seizures (8.1 years). The 1-year survival rate for cats with idiopathic seizures (0.82) was longer than that for cats with reactive (0.50) or symptomatic (0.16) seizures. Seizure etiology was symptomatic or reactive in most cats. Underlying disease was not associated with seizure type. Cats with idiopathic seizures lived longer than did cats with reactive or symptomatic seizures but were also younger.

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... Feline epilepsy is classified into idiopathic, structural, and unknown cause according to the consensus proposal by the International Veterinary Epilepsy Task Force (IVETF; Berendt et al., 2015). While, traditionally, the presence of idiopathic epilepsy in this species has been questioned, researchers have demonstrated recently that a considerable number of cats with recurrent seizures have no identifiable underlying structural conditions (Barnes et al., 2004;Schriefl et al., 2008;Bailey and Dewey, 2009;Pakozdy et al., 2010Pakozdy et al., , 2014Wahle et al., 2014). While spontaneous genetic epilepsy has not been documented other than in a closed colony in a research setting called familial spontaneous epileptic cats (FSEC; Kuwabara et al., 2010). ...
... A recent epidemiologic study reported the prevalence of epilepsy (including all types i.e., idiopathic, structural, and unknown cause) in cats under primary veterinary care in the United Kingdom at 0.04 %, based on the assessment by first-opinion veterinarians (O'Neill et al., 2020), while it has been reported in higher prevalence at 1.6-2.4 % in the referral setting (Schriefl et al., 2008;Pakozdy et al., 2010). In the referral setting, the percentage of idiopathic and/or epilepsy of unknown cause (EUC) in cats was reported between 22 % and 54 %, and that of structural epilepsy was 34-50 % (Schriefl et al., 2008;Pakozdy et al., 2010;Wahle et al., 2014). ...
... % in the referral setting (Schriefl et al., 2008;Pakozdy et al., 2010). In the referral setting, the percentage of idiopathic and/or epilepsy of unknown cause (EUC) in cats was reported between 22 % and 54 %, and that of structural epilepsy was 34-50 % (Schriefl et al., 2008;Pakozdy et al., 2010;Wahle et al., 2014). ...
Article
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Feline epilepsy is treated with antiseizure medications, which achieves fair to good seizure control. However, a small subset of feline patients with drug-resistant epilepsy requires alternative therapies. Furthermore, approximately 50% of cats with epileptic seizures are diagnosed with structural epilepsy with or without hippocampal abnormality and may respond to surgical intervention. The presence of hippocampal pathology and intracranial tumors is a key point to consider for surgical treatment. This review describes feline epilepsy syndrome and epilepsy-related pathology, and discusses the indications for and availability of neurosurgery, including lesionectomy, temporal lobectomy with hippocampectomy, and corpus callosotomy, for cats with different epilepsy types.
... Based upon a recent classification system by the International Veterinary Epilepsy Task Force Consensus Report in 2015, EUC replaces former terms such as idiopathic epilepsy and primary epilepsy and embraces categories such as cryptogenic epilepsy and presumed idiopathic epilepsy . Reported prevalences of feline EUC range between 22 and 54% (Rusbridge, 2005;Schriefl et al., 2008;Wahle et al., 2014). The main characteristic feature in cats with EUC is absence of pathological findings by diagnostic imaging and CSF analysis and/or a history of seizures with no abnormalities detected on neurologic examination during interictal periods. ...
... The median age at onset of seizures in EUC is generally <7 years, but the range varies considerably between 0.4 and 14.4 years and no breed or sex predilections could be identified (Schriefl et al., 2008;Pakozdy et al., 2010;Moore et al., 2013;Wahle et al., 2014). ...
... In this study, 68% of cats with EUC survived for a mean follow-up time period of 3.2 years (range: 1-11 years), and seizures were successfully controlled with AED's in 71% of the cats. Similarly, previous studies reported high survival rates and good outcomes in cats with EUC (Schriefl et al., 2008;Pakodzy et al., 2010;Pakozdy et al., 2012;Finnerty et al., 2014;Wahle et al., 2014). However, in many cats seizures were poorly controlled, and 21% were euthanized or died as a consequence of their seizures in the present retrospective study. ...
... a,7-11 In 3 larger retrospective studies, a total of 233 epileptic cats were evaluated and 77 (33%) classified as IE. 7,11,12 At present, there is no test to confirm IE, so the diagnosis can only be suspected based on the elimination of possible etiologic factors. The inherent weakness in the diagnosis of IE will remain until other, eg, genetic, tests become available. ...
... Seizures in cats are frequently complex focal seizures with or without secondary generalization. 10,11,14,15 The ictal signs frequently include drooling, facial twitching, tremor, rapid running, mydriasis, hypersalivation, urination, and defecation. During focal seizure, a cat can remain in sternal recumbency or can show running or climbing activity. ...
... On average, cats with IE are younger than cats with SE, with the mean age of onset in the IE/SE groups of 4.6/8.4 and 3.5/ 8.2 years in the 2 studies. 7,11 The information is of limited diagnostic value as there is an overlap between the groups. Nevertheless, a young adult cat is more likely to have IE and an older cat more likely to have SE. ...
... There is a paucity of literature about feline epilepsy compared to canine epilepsy, however epileptic seizures are a common neurological manifestation in cats with an estimated prevalence in a referral hospital population of 0.5-3.5% [1,2]. Idiopathic epilepsy (IE) has not been studied in cats as thoroughly as in dogs but between 21-59% of cats presenting with recurrent seizures can be diagnosed with IE [3][4][5]. ...
... Eight studies [4,[25][26][27][28][29][30][31] assessed the efficacy of phenobarbital as a monotherapy agent or in combination with other AEDs (two studies), providing a total size of 137 cats. Based on the 95% CI, in all the studies but three Volk et al. [28] Klang et sl. ...
... PU, polyuria; PP, polyphagia; PBr, potassium bromide; PO, per os; SID, semel in die (once daily); TID, ter in die (three times daily); w, week(s); year(s); y [4,26,31] (63%), the majority of the study population was treated successfully. In one of these studies though [26], phenobarbital was only used to treat a specific type of epileptic seizures in cats, i.e. feline auditory reactive seizures (FARS), which might have biased the results for the drug's overall efficacy to control seizures. ...
Article
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Background: Understanding the efficacy and safety profile of antiepileptic drugs (AEDs) in feline epilepsy is a crucial consideration for managing this important brain disease. However, there is a lack of information about the treatment of feline epilepsy and therefore a systematic review was constructed to assess current evidence for the AEDs' efficacy and tolerability in cats. The methods and materials of our former systematic reviews in canine epilepsy were mostly mirrored for the current systematic review in cats. Databases of PubMed, CAB Direct and Google scholar were searched to detect peer-reviewed studies reporting efficacy and/or adverse effects of AEDs in cats. The studies were assessed with regards to their quality of evidence, i.e. study design, study population, diagnostic criteria and overall risk of bias and the outcome measures reported, i.e. prevalence and 95% confidence interval of the successful and affected population in each study and in total. Results: Forty studies describing clinical outcomes of AEDs' efficacy and safety were included. Only two studies were classified as "blinded randomised controlled trials". The majority of the studies offered high overall risk of bias and described low feline populations with unclear diagnostic criteria and short treatment or follow-up periods. Individual AED assessments of efficacy and safety profile showed that phenobarbital might currently be considered as the first choice AED followed by levetiracetam and imepitoin. Only imepitoin's safety profile was supported by strong level of evidence. Imepitoin's efficacy as well as remaining AEDs' efficacy and safety profile were supported by weak level of evidence. Conclusions: This systematic review reflects an evidence-based assessment of the published data on the AEDs' efficacy and safety for feline epilepsy. Currently, phenobarbital is likely to be the first-line for feline epileptic patients followed by levetiracetam and imepitoin. It is essential that clinicians evaluate both AEDs' effectiveness and tolerability before tailoring AED to the individual patient. Further studies in feline epilepsy treatment are by far crucial in order to establish definite guidelines for AEDs' efficacy and safety.
... Similar findings are reported by Rusbridge (2005) and Barnes (2004), where hepatic encephalopathy was the predominant diagnosis in the metabolic group of diseases. However, Schriefl (2008) report that the percentage of reactive seizures is higher. Kline (1998) indicated that reactive seizures due to hepatic encephalopathy occurred infrequently in cats. ...
... Idiopathic epilepsy is recognized in cats; however, cats are generally older at the onset of seizures than are dogs with idiopathic epilepsy (Bailey et al., 2008). Although idiopathic epilepsy was thought to be rare in cats (Bailey and Dewey, 2009;Berg and Scheffer, 2011;Kline, 1998;Pakozdy et al., 2010;Schrieflet al., 2008), new evidence suggest that between 21% and 59% of cases are idiopathic (Cizinauskas et al., 2011;Quesnel et al., 1997b;Schriefl et al., 2008), another study indicate a 25% of cats with seizures as having idiopathic epilepsy (Schriefl et al., 2008). Other authors have defined idiopathic epilepsy as inherited epilepsy (Parent and Quesnel, 1996;Quesnel et al., 1997b;Shell, 2000). ...
... Idiopathic epilepsy is recognized in cats; however, cats are generally older at the onset of seizures than are dogs with idiopathic epilepsy (Bailey et al., 2008). Although idiopathic epilepsy was thought to be rare in cats (Bailey and Dewey, 2009;Berg and Scheffer, 2011;Kline, 1998;Pakozdy et al., 2010;Schrieflet al., 2008), new evidence suggest that between 21% and 59% of cases are idiopathic (Cizinauskas et al., 2011;Quesnel et al., 1997b;Schriefl et al., 2008), another study indicate a 25% of cats with seizures as having idiopathic epilepsy (Schriefl et al., 2008). Other authors have defined idiopathic epilepsy as inherited epilepsy (Parent and Quesnel, 1996;Quesnel et al., 1997b;Shell, 2000). ...
Article
Full-text available
Epileptic seizures are the most common neurological disorder in the clinical setting. Their etiology is multifactorial and is mainly divided into structural, reactive and idiopathic epilepsy. Structural epilepsy can be caused by vascular events, inflammatory conditions (encephalitis), traumatic injuries, neoplasia, congenital and inherited (degenerative) disorders. Reactive epilepsy is caused by exposure in toxins or metabolic derangements. Although idiopathic epilepsy was thought to be rare in cats, it is now established as a common cause. Epileptic seizures in cats appear with various clinical presentations including generalized, focal with or without secondary generalization epileptic seizures. Diagnostic investigation is crucial in order to establish final diagnosis and to determine the therapeutic plan. Diagnostics include physical and neurological examination with detailed history (drug or toxin exposure), routine hematology (CBC, biochemistry, urinalysis), specific laboratory tests if concurrent or metabolic disease are suspected, advanced diagnostic imaging (CT/MRI) whether intracranial disease is suspected and cerebrospinal fluid (CSF) analysis. Most commonly used antiepileptic drugs (AED) in cats are phenobarbital and levetiracetam. Bromide is contraindi-cated in cats due to severe respiratory disease caused as an adverse life-threatening reaction. Diazepam is an emergency AED used to eliminate cluster seizures or status epilepticus but it should be avoided as a long-term medication because it has been associated with fatal hepatotoxicity. Gabapentin in another potential antiepileptic drug however its long-term efficacy has to be evaluated. Prognosis depends on the underlying etiology and treatment response. In most cats quality of life is improved and (>50% reduction of epileptic seizures) regardless of etiology. The complete remission of epileptic seizures in cats is rare and most cats should be maintained on anti-epileptic therapy.
... Epilepsy is a common neurologic disorder in cats (Smith et al., 2009;Stanciu et al., 2017). Although epileptic seizures are reported less frequently in cats than in dogs, they are still one of the most commonly seen neurologic disorders in cats, with an overall reported prevalence of 2.1% (Schriefl et al., 2008). Epileptic seizures in cats can be a diagnostic challenge for clinicians, due to difficulties in obtaining a detailed history, the wide variety of clinical signs, including focal seizures which produce orofacial twitches and aggression (Pazkozdy et al., 2010), and because less data are available on treatment protocols and their efficacy in comparison to dogs. ...
... This is a diagnosis of exclusion, based in dogs upon normal interictal neurological examination, normal blood test results (tier 1 confidence level), normal magnetic resonance imaging (MRI) (Raimondi et al., 2017) and cerebrospinal fluid (CSF) results (tier 2 confidence level), and interictal or ictal electroencephalography (EEG) findings (tier 3 confidence level; De Risio et al., 2015). Historically, IE in cats was believed to be rare, however, more recent studies have reported that approximately 30% of cats with epileptic seizures have idiopathic epilepsy (Barnes et al., 2004;Schriefl et al., 2008;Pakozdy et al., 2010). In comparison to canines, genetic epilepsy in cats is rare. ...
... In a retrospective study conducted by Schriefl at al. (2008) reactive seizures were diagnosed in 22.0% (n=20/91) of cats presented for epileptic seizure evaluation within a 5year period, in another study performed by Pakozdy et al. (2010) secondary epilepsy was diagnosed in 62% of cats (n=78/125) presented with recurrent seizures; however, no detailed data regarding most common causes for reactive seizures are available. ...
Article
Epileptic seizures are a common indication for neurological evaluation. This retrospective study reviewed 789 cats referred for epileptic seizure evaluation to the Department of Small Animal Medicine and Surgery of the University of Veterinary Medicine in Hannover, between 1998 and 2017. The aim of this study was to determine common causes for reactive seizures (RS) in cats. Reactive seizures were diagnosed in 62 (7.9%) of 789 feline patients. The most common cause of RS was presumptive or confirmed intoxication (n = 34/62; 54.8%). Toxins included permethrin (n = 5/62; 8.1%), fipronil (n = 1/62; 1.6%), and pesticide (n = 1/62; 1.6%). Other common causes were hepatic and renal encephalopathy (n = 6/62; 9.7% each), hypertension (n = 5/62; 8.1%), hyperthyroidism (n = 3/62; 4.8%), hypoglycaemia (n = 3/62; 4.8%), and hyperglycaemia (n = 1/62; 1.6%). Most commonly, cats with RS presented with generalised tonic–clonic seizures (n = 25/62; 40.3%). A single status epilepticus was observed in 9.7% (n = 6/62) and 4.8% (n = 3/62) presented only with cluster seizures. Focal seizures were the only presenting sign in 3.2% (n = 2/62) of cases, however in 4.8% (n = 3/62) they were accompanied by tonic–clonic seizures. The mean age of all cats presented for RS was 10.8 years. In the intoxication group, the mean age was 2.9 years. Intoxication (confirmed or presumptive) was the most common cause of RS identified. Clinicians should suspect intoxication when other causes of RS are excluded; when there are appropriate historical findings; when the cat is frequently unobserved by the owner; when symptomatic treatment leads to cessation of epileptic seizures; and when seizures do not recur after treatment has been discontinued.
... In previous studies (Barnes et al., 2004;Rusbridge, 2005), hepatic encephalopathy was the predominant diagnosis in the metabolic group of diseases in comparison to others that indicate infrequent seizure occurrence due to hepatic encephalopathy (Kline, 1998). A more recent study indicated a higher percentage of feline seizure cases due to metabolic/toxic causes (Schriefl et al., 2008).Seizures due to toxicosis appeared in three cats (1 cat was exposed to organophosphates and 2 on permethrin product) in the current study. Thus, in many cats presented with seizures, a careful history of drug use and potential of toxin exposure is essential (O' Brien, 1998). ...
... This finding is in parallel with another study in which euthanasia was elected soon after a diagnosis was established due to poor prognosis in cats (Barnes et al., 2004),or due to unacceptable seizure frequency in a study with epileptic dogs (Berendt et al., 2007). Both cats and dogs had a poor prognosis when status epilepticus appear (Bateman and Parent, 1999;Schriefl et al., 2008). Despite the providing data, there was no evidence supporting this hypothesis in our study. ...
Article
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The purpose of the current study was to describe seizure types, aetiology, treatment response and outcome in 30cats with recurrent seizures. This retrospective case series study included the medical records of client owned cats, admitted to the Clinic of Companion Animals for seizure disorders, from 2002 to 2018. Recorded data included history, seizure type, physical and neurological examination findings, blood pressure measurements, complete blood counts, serum biochemistry profile and urinalysis, tentative/final diagnosis, treatment, hospitalization and long-term outcome. A total of 298 feline neurology cases were examined during the study period. Of those, 38 cases were admitted for seizure disorders and 30 met the inclusion criteria. Median age on admission was 38,2 months (3,1 years) (range 2 months-14 years old).Seizure types, as per owner description, were generalized (26 cats), focal with secondary generalization (3 cats), focal (2 cats) and complex (1 cat). Cluster seizures appeared at least once in 18/30 and status epilepticus in 7/30. Different seizure types were also recorded in individual cases. Fifteen cats (15/30) were hospitalized at least once and the duration of hospitalization ranged from 1-10 days. In most cases, in which diagnosis was established, epilepsy wassecondary (25/30), due to previous head trauma(11/30),metabolic (1/30), or inflammatory (4/30) disease, arterial hypertension (3/30), toxicosis (3/30) and intracranial neoplasia (2/30).Congenital hydrocepha-lus was detected in 1 cat. Tentative diagnosis could not be established in 5cats; however differential diagnosis included inflammatory or neoplastic encephalopathies.Antiepileptic drug monotherapy (phenobarbital or levetiracetam) was sufficient to control the seizures in 14 cases, while administration of combination therapy with 2 or more antiepileptic drugs was required in 5 cases (phenobarbital, levetiracetam, gabapentin). Successful control was achieved in 11/30 animals for 1-5 years. Seven cats required intensive care at least once due to status epilepticus. Until today, eighteen (18/30) cats are still alive and 11 died or were euthanized.Although in most cases epilepsy was secondary, seizure control was adequate and quality of life (QoL) was improved with antiepileptic drugs when metabolic, inflammatory and neoplastic encephalopathies were excluded.
... En el mismo estudio, 2 de 136 perros fueron clasifi-cados como probables epilépticos sintomáticos en base a los hallazgos clínicos interictales, a pesar que los estudios complementarios resultaron normales. Otro trabajo realizado en gatos en los que se empleó IRM y/o examen pos mortem como estrictos criterios de inclusión, determinó la presencia de ECD en el 22% de los individuos examinados (Wahle et al. 2014), contra porcentajes mucho más altos (25 al 66%) comunicados en otros trabajos donde la utilización de imágenes sofisticadas fue más limitada (Barnes et al. 2004;Pakozdy et al. 2010;Rusbridge 2005;Schriefl et al. 2008;Schwartz-Porsche y Kaiser 1989). ...
... La clasificación de las Epilepsias y de los Síndromes Epilépticos realizada en el año 1989 (Commission on Classification and Terminology, ILAE 1989) fue ampliamente reconocida y aplicada por la comunidad científica en una multitud de estudios clínicos y epidemiológicos, no sólamente en Medicina Humana sino también en Medicina Veterinaria (Berendt y Gram 1999;Fischer y Hϋlsmeyer 2013;Jokinen et al. 2007;Pakozdy et al. 2014;Pellegrino et al. 2011a;Pellegrino 2003Pellegrino , 2014Pellegrino , 2015Podell et al. 1995;Thomas 2010 (Brini et al. 2004;Fatzer et al. 2000;Pakozdy et al. 2011;Schmied et al. 2008;Schriefl et al. 2008;Vanhaesebrouck et al. 2012) es un claro ejemplo de constelación distintiva. El resto de las EI clásicas de perros y gatos quedarían incluídas en el grupo menos específico de las ECD. ...
... In previous studies (Barnes et al., 2004;Rusbridge, 2005), hepatic encephalopathy was the predominant diagnosis in the metabolic group of diseases in comparison to others that indicate infrequent seizure occurrence due to hepatic encephalopathy (Kline, 1998). A more recent study indicated a higher percentage of feline seizure cases due to metabolic/toxic causes (Schriefl et al., 2008).Seizures due to toxicosis appeared in three cats (1 cat was exposed to organophosphates and 2 on permethrin product) in the current study. Thus, in many cats presented with seizures, a careful history of drug use and potential of toxin exposure is essential (O' Brien, 1998). ...
... This finding is in parallel with another study in which euthanasia was elected soon after a diagnosis was established due to poor prognosis in cats (Barnes et al., 2004),or due to unacceptable seizure frequency in a study with epileptic dogs (Berendt et al., 2007). Both cats and dogs had a poor prognosis when status epilepticus appear (Bateman and Parent, 1999;Schriefl et al., 2008). Despite the providing data, there was no evidence supporting this hypothesis in our study. ...
... Epileptic seizures affect 1-2% of the general feline population (Schriefl et al., 2008). Seizure manifestations can differ from those typically seen in dogs, but the underlying causes of seizure activity appear to be similar and include both idiopathic (IE) and structural epilepsies (SE). ...
... Seizure manifestations can differ from those typically seen in dogs, but the underlying causes of seizure activity appear to be similar and include both idiopathic (IE) and structural epilepsies (SE). Despite many references and controversial data published about feline IE (Schriefl et al., 2008), only one large-scale study has examined the aetiology and classification of feline epilepsy (Pakozdy et al., 2010). The aim of this study was to evaluate aetiology in a population of cats, and to provide information to improve clinical reasoning when investigating seizures in cats. ...
Article
We sought to to identify the association between clinical risk factors and the diagnosis of idiopathic epilepsy (IE) or structural epilepsy (SE) in cats, using statistical models to identify combinations of discrete parameters from the patient signalment, history and neurological examination findings that could suggest the most likely diagnosis. Data for 138 cats with recurrent seizures were reviewed, of which 110 were valid for inclusion. Seizure aetiology was classified as IE in 57% and SE in 43% of cats. Binomial logistic regression analyses demonstrated that pedigree status, older age at seizure onset (particularly >7 years old), abnormal neurological examinations, and ictal vocalisation were associated with a diagnosis of SE compared to IE, and that ictal salivation was more likely to be associated with a diagnosis of IE than SE. These findings support the importance of considering inter-ictal neurological deficits and seizure history in clinical reasoning.
... Over the past two decades, several case reports on feline hippocampal necrosis (HN) have been published in Europe, Asia, and the United States [1][2][3][4][5][6][7][8][9], indicating that necrosis of the hippocampus and piriform lobe associated with the appearance of epileptic seizures in feline patients is a worldwide phenomenon. Magnetic resonance imaging (MRI) is routinely used in human epileptic patients [10][11][12], and hippocampal sclerosis (HS) has been identified as the single most frequently detected feature of mesial temporal lobe (TL) epilepsy in humans [11]. ...
... As a group, MR images of the TL of cats suffering from any kind of epileptic seizure did not differ significantly from those of cats without epileptic disorders. However when stratified according to seizure semiology, or Previous studies have suggested that alterations in the feline TL visible on MR images were caused by various underlying conditions, including astrogliosis, oedema, hypoxia, idiopathic HN and HS, inflammation, intracranial infection, ischemia, malformation and neoplastic conditions [1][2][3][4][5][6][7][8][9]. A potential toxin or infectious agent cannot be ruled out, nor can genetic predisposition or febrile seizures early in life, as described in human medicine [14]. ...
Article
Full-text available
Background Hippocampal necrosis in cats has been reported to be associated with epileptic seizures. Magnetic resonance imaging (MRI) features of temporal lobe (TL) abnormalities in epileptic cats have been described but MR images from epileptic and non-epileptic individuals have not yet been systematically compared. TL abnormalities are highly variable in shape, size and signal, and therefore may lead to varying evaluations by different specialists. The aim of this study was to investigate whether there were differences in the appearance of the TL between epileptic and non-epileptic cats, and whether there were any relationships between TL abnormalities and seizure semiologies or other clinical findings. We also investigated interobserver agreement among three specialists. Methods The MR images of 46 cats were reviewed independently by three observers, who were blinded to patient data, examination findings and the review of the other observers. Images were evaluated using a multiparametric scoring system developed for this study. Mann–Whitney U-tests and chi-square were used to analyse the differences between observers’ evaluations. The kappa coefficient (k) and Fleiss’ kappa coefficient were used to quantify interobserver agreement. ResultsThe overall interobserver agreement was moderate to good (k =0.405 to 0.615). The MR scores between epileptic and non-epileptic cats did not differ significantly. However, there was a significant difference between the MR scores of epileptic cats with and without orofacial involvement according to all three observers. Likewise, MR scores of cats with cluster seizures were higher than those of cats without clusters. Conclusion Cats presenting with recurrent epileptic seizures with orofacial involvement are more likely to have hippocampal pathologies, which suggests that TL abnormalities are not merely unspecific epileptic findings, but are associated with a certain type of epilepsy. TL signal alterations are more likely to be detected on FLAIR sequences. In contrast to severe changes in the TL which were described similarly among specialists, mild TL abnormalities may be difficult to interpret, thus leading to different assessments among observers.
... La mención de un tipo de crisis debe traer a la mente una entidad específica, aunque a veces con subcategorías y variaciones entre ellas. De esta forma, una buena clasificación permitiría agrupar razonablemente cohortes de pacientes para el descubrimiento de etiologías, incluyendo factores genéticos, investigación de los mecanismos fundamenta- Brini et al. 2004;Fatzer et al. 2000;Marioni-Henry et al. 2012;Pakozdy et al. 2011;Schmied et al. 2008;Schriefl et al. 2008;Vanhaesebrouck et al. 2012), y la Epilepsia Audiogénica Felina (Lowrie et al. 2016). ...
... Una epilepsia focal caracterizada por crisis de tremores generalizados en animales atáxicos muy jóvenes de raza Lagotto Romagnolo, puede asociarse específicamente a Epilepsia Benigna Juvenil Familiar recesiva, especialmente si se cuenta con un registro EEG que muestre descargas epileptiformes unilaterales en las regiones occipital y centroparietal, con IRM normales (Jokinen et al. 2007;Seppala et al. 2011). Una epilepsia focal de inicio motor con signos autonómicos y conductuales en un gato, que además presenta en las IRM alteraciones inflamatorias bilaterales en la región hipocampal, puede asociarse al diagnóstico sindrómico de Necrosis del Hipocampo y del Lóbulo Piriforme Felina (Adagra y Piripi 2014; Alagarda et al. 2009;Brini et al. 2004;Fatzer et al. 2000;Marioni-Henry et al. 2012;Pakozdy et al. 2011;Schmied et al. 2008;Schriefl et al. 2008;Vanhaesebrouck et al. 2012). Una epilepsia combinada generalizada y focal en un gato, dependiendo del tipo de crisis focal y del desencadenante de las crisis generalizadas puede asociarse, especialmente si es posible acceder a EEG e IRM, con Epilepsia Espontánea Familiar Felina (Kuwabara et al. 2010), o con Epilepsia Audiogénica Felina (Lowrie et al. 2016). ...
... Nineteen months later the cat started to suffer seizures again every 2-3 weeks. At that point phenobarbitone serum levels were 5 mg/l (reference interval [RI] [15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] and the dosage was increased. For 1 year after this relapse, the patient remained seizure-free. ...
... FHN has been reported in one publication as a relatively frequent aetiology for feline seizures, ranging between 11% and 25%. 5 Other authors considered it a rare disease or did not mention it among the causes of feline seizures at all. 13,14,16 The aetiology of FHN remains unclear: there is some evidence supporting a vascular insult as the primary cause of the disease; 4,17 however, the aetiology remains most frequently unknown. A neoplastic process affecting the brain and secondarily damaging the hippocampus can be considered as a differential diagnosis. ...
Article
Case series summary Seven cases of feline hippocampal and piriform lobe necrosis (FHN) are described, with particular emphasis on clinical, radiographic and histopathological correlations. FHN is an uncommon acute epileptic condition resembling human autoimmune limbic encephalitis and temporal lobe epilepsy. Seizures are typically focal and feature uni- or bilateral orofacial or head twitching, hypersalivation, lip smacking, mydriasis, vocalisation and motionless staring, with inter-ictal behavioural changes such as unprovoked aggression and rapid running. Emerging evidence supports an autoimmune aetiology, although disruption of hippocampal architecture secondary to brain neoplasia has also been recognised. Most commonly, however, the underlying cause remains unknown. Diagnosis is achieved clinically and with brain MRI; electroencephalography and voltage-gated potassium channel-complex autoantibodies are currently the subject of research. Affected cats are frequently refractory to conventional antiepileptic treatment. Relevance and novel information Following a review of the literature, including potential complicating factors and comparisons with human medicine, the hippocampus and piriform lobe are proposed as the neuroanatomical localisation for focal seizures with orofacial involvement in cats, regardless of aetiology.
... Diversos trabalhos sobre enfermidades neurológicas geralmente consistem em relatos de casos ou estudos retrospectivos de uma determinada doença (Lane et al. 1994, Kline et al. 1994, Vernau et al. 2001, Marioni-Henry et al. 2004, Tomek et al. 2006, Schriefl et al. 2008) e poucos são aqueles demonstrando as principais doenças neurológicas que acometem gatos (Bradshaw et al. 2004). Uma análise retrospectiva sobre enfermidades neurológicas em cães foi realizada por Chaves e colaboradores em 2014 e verificaram que as doenças degenerativas e inflamatórias/ infecciosas foram as que prevaleceram, o que não necessariamente possam ser as mesmas que afetam os gatos. ...
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RESUMO: Foi realizado um estudo epidemiológico retrospectivo de gatos com doenças neurológicas atendidos em um Hospital Veterinário Universitário entre 2001 e 2014. O objetivo foi identificar e caracterizar a idade, o sexo, a raça, as doenças neurológicas e classificá-las de acordo com a região anatômica e o acrônimo DINAMIT-V. Foram observados 155 gatos com doenças neurológicas em 13 anos, sendo o diagnóstico confirmado em 112 gatos (72,2%) e presuntivo em 43 (27,8%). Gatos sem raça definida (77,9%) foram os mais comuns, seguido de gatos da raça persa e siamesa. Os locais mais afetados foram medula espinhal entre T3-L3 (28,4%) e tálamo-córtex (24,5%). A maioria dos gatos (43,9%) foi diagnosticada com doença traumática, principalmente trauma de medula espinhal, seguida de doença inflamatória/infecciosa (33,5%). Pode se concluir que a maior prevalência das doenças neurológicas de gatos envolve a medula espinhal e o tálamo-córtex, sendo as traumáticas as mais frequentes. Os dados obtidos podem auxiliar em futuros estudos sobre a frequência e a distribuição das principais doenças neurológicas em gatos.
... B. Belgischer Schäferhund, Border Terrier und Labrador Retriever, können deutlich höhere Prävalenzen vorliegen [2]. Für Katzen wird der relative Anteil der mit Krampfanfällen vorgestellten Tiere mit 2,1 % angegeben [3]. Zur Verwendung einer einheitlichen Terminologie sowie zur Etablierung eines Konsens bezüglich Klassifikation, Diagnostik und Therapie wurde 2014 die International Veterinary Epilepsy Task Force (IVETF) gegründet. ...
Article
Zusammenfassung Epilepsie ist eine neurologische Erkrankung, die dem Kleintierpraktiker im klinischen Alltag häufig begegnet. Die Erkrankung umfasst eine Vielzahl klinischer Ausprägungen und Ätiologien und die klinische Aufarbeitung bedarf in vielen Fällen einer kostenaufwendigen und umfangreichen Diagnostik. Diese ist notwendig, um eine metabolische Ursache für die Krampfanfälle festzustellen oder auszuschließen bzw. zwischen idiopathischer und struktureller Epilepsie unterscheiden zu können. Für die Klassifikation der Epilepsie ist die Untersuchung mittels Magnetresonanztomografie (MRT) ein zentraler Bestandteil der Diagnosefindung, die sich entscheidend auf Therapie und Prognose auswirkt. Die Standardisierung von MRT-Protokollen hat große Bedeutung, um eine einheitliche Untersuchung und vergleichbare Ergebnisse zu erzielen. Dies kann die Kommunikation und Interaktion zwischen klinischen Einrichtungen erleichtern und die Möglichkeit bieten, noch unerkannte strukturelle Veränderungen im MRT zu erfassen. Dieser Übersichtsartikel beschäftigt sich im Zentralen mit der Definition und Klassifikation der Epilepsie sowie der bildgebenden Diagnostik der Epilepsie beim Hund und nimmt Bezug auf Statistiken und Empfehlungen von Spezialisten zur klinischen Fallaufarbeitung.
... As convulsões em gatos ocorrem devido a doenças intra ou extracranianas [1]. As causas não infecciosas mais comuns são inflamação, neoplasia, doença vascular e encefalopatia metabólica ou tóxica [1,15]. Já a meningoencefalite está geralmente associada a infecções, como toxoplasmose [12], peritonite infecciosa felina (PIF) [5,12] ou coronavírus felino [5], mas podem ser causadas por infecção bacteriana em orelha média ou interna [12]. ...
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Background: Meningoencephalitis in cats is usually related to infectious diseases but may also be caused by the extension of bacterial infections originated in the middle or inner ear. This paper seeks to report on a case of encephalitis due to an infection in the middle/inner ear in a 15-year-old cat. The diagnosis was made through brain CT scan and culture and antibiogram of material collected during a ventral osteotomy of the tympanic bulla and reported grave intravascular haemolysis associated to the treatment with antimicrobial imipenem with cilastatin sodium that has already been described in humans but not in small animals in the researched literature. Case: A 15-year-old, male, castrated, Siamese cat was brought to the Veterinary Clinical Hospital of the UFRGS. The animal presented pyrexia and hyporexia, tested negative in the immunoenzymatic test to detect antigens of the FeLV and antibodies of the FIV. The animal had a history of three episodes of tonic convulsion within two days and otitis that had gone untreated for 10 months prior to the consultation, with apparent spontaneous remission. After blood tests, serum biochemistry profile, abdominal ultrasound scan, chest x-rays and CT scan was requested. It revealed middle and inner otitis in the right ear. It was performed a ventral osteotomy of the right tympanic bulla. Material was collected for culture and antibiogram. It was confirmed that the animal had an inner otitis of bacterial origin by multi-resistant Klebsiella spp. that was sensitive only to antimicrobial imipenem with cilastatin sodium. Fifteen days into the treatment with this antibacterial combination, grave haemolysis was observed, probably associated to the use of the medicine. The patient died on the 17th day of the treatment which was not interrupted as per its owner’s decision. At necropsy, both in the tympanic bulla and liver were found mucous content and whitish lumps. The material collected from the tympanic bulla and cerebrospinal liquid were cultured post-mortem when the bacteria Klebsiella sp. was isolated in the CNS and no bacterial growth was observed in the right tympanic bulla. Discussion: This makes it possible to deduce that there was an intracranial expansion of the otitis which would explain the convulsions and, that due to the use of the antimicrobial agent, the growth of Klebsiella sp. in the tympanic bulla was inhibited. The final diagnosis was bacterial otitis with probable bacterial migration to the brain and liver. Suppurative meningoencephalitis caused by the expansion of the inflammation deriving from middle/inner otitis has been reported as being the cause of convulsions in cats with bacterial isolation. The bacteria that was isolated from the tympanic bulla is in agreement with the microbiota present in middle/inner otitis in cats. Regarding haemolysis, there are no reports that link the use of carbapenems in small animals to it or that mention what the safe therapeutic dosage should be if they were administered. Regarding humans, there have been various reports of haemolytic anaemia caused by this type of medicine including carbapenems. It is also known that, in in vitro tests, imipenem may cause inhibition due to competition from human erythrocyte-glutathione reductase, in charge of defending the erythrocyte against haemolysis. It has been concluded that meningoencephalitis caused by middle/inner otitis must be included as a differential diagnosis in case of convulsions in cats. Additionally, further studies must be carried out in order to determine both the efficacy and the toxicity of carbapenems in veterinary patients, including studies of the occurrence of grave haemolysis after they are administered.
... Postiktal faz su resi ve klinik belirtilerin ciddiyeti, iktusun su resi ve ciddiyeti ile ilişkili olmayabilir. Tonik-klonik no betlerin, kedilerde en yaygın go ru len genel no bet tipi oldug u da bildirilmiştir (15,16). Preiktal fazda kedilerde artan saldırganlık, sesler çıkarma (tıslama, hırlama ya da ag lama gibi), huzursuzluk (du zensizce dolaşmak), kaygı, saklanma, u rkeklik ya da artan şefkat (sahiplerine sıg ınmak) gibi davranışlar go ru lebilir. ...
... This finding is consistent with previous studies in cats. 3,4 In dogs, males may have increased odds of developing seizure disorders, 7,8,58 but this observation is complicated by effects of neutering as well as different sex predisposition to seizures among specific dog breeds. 58,59 Despite the large numbers of cats affected by RSD in our study, no antiseizure medications currently are licensed for use in cats in the UK. ...
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Background: Little epidemiological evaluation of recurrent seizure disorders in cats currently exists in veterinary literature. Objectives: To report the prevalence and risk factors for recurrent seizure disorders (RSD) and epilepsy in cats presented to primary care veterinary practices in the United Kingdom (UK). Animals: A total of 285 547 cats under veterinary care during 2013 presenting to 282 primary care clinics in the UK. Methods: Cohort study using multivariable logistic regression modeling for risk factor analysis. Results: There were 458 confirmed RSD cases, giving a 1-year period prevalence of 0.16% (95% confidence interval [CI], 0.15-0.18). A subset of 114 (24.89%) cases was recorded as having epilepsy, giving a 1-year period prevalence of 0.04% (95% CI, 0.03-0.5). Increasing age was significantly associated with increasing odds of RSD. Breed, sex, neuter status, and body weight were not associated with RSD. Epilepsy was most frequently diagnosed in adult to middle-aged cats. Cats aged 3.0 to <6.0 years had 3.32 times higher odds of epilepsy diagnosis compared to cats <3.0 years of age. Insured cats were more likely to be diagnosed with epilepsy compared to noninsured cats. Conclusions and clinical importance: Although less common than in dogs, RSD and epilepsy still comprise an important disorder group in the UK cat population. Aging is a significant risk factor for these disorders in cats.
... The term partial is no longer used and is replaced by focal seizure. [3] [4] In contrast, our study concluded that generalized seizure was the most predominant type and generalised tonic clonic was the most common subtype. Determining the correct type of seizure is most appropriate, since it guides towards aetiology, alters the treatment strategy and affects prognosis. ...
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BACKGROUND This study was taken up to study the distribution of type of seizures and to evaluate the aetiological profile among patients presenting with seizures in a tertiary care centre METHODS This was an observational prospective study done from April 2014 - March 2015 in Government Stanley Hospital. The study included 150 patients above 12 years of age presenting with acute symptomatic seizures. Detailed history to ascertain the type of seizure and clinical examination was done. Routine investigations, EEG and imaging of the brain was done for all patients. Data recorded and analysed. RESULTS Among 150 patients included in the study generalised seizures accounted for the majority of seizures of around 92% followed by focal seizures 6% and others 2%. Among generalised, generalised tonic clonic seizure was the most common subtype. Alcohol related seizures was the most common cause followed by CNS infection. CONCLUSIONS Our study concluded that generalised seizure is the predominant type of seizure and alcohol related seizures was the most common cause among patients presenting in Govt. Stanley Medical Hospital
... El reconocimiento y la definición de distintos síndromes epilépticos ha dado una nueva dimensión al estudio de las epilepsias al resaltar, junto a síntomas y signos clínicos y hallazgos electroencefalográficos, el valor de otros exámenes complementarios (por ej., la tomografía axial computada -TAC-y las imágenes por resonancia magnética -IRM-), destacando así la investigación etiológica. Actualmente la epilepsia humana comprende más de 40 síndromes, especificando edad de inicio, respuesta a estímulos, características de las crisis y de las anormalidades EEG ( (Brini et al. 2004;Fatzer et al. 2000;Pakozdy et al. 2011;Schmied et al. 2008;Schriefl et al. 2008;Vanhaesebrouck et al. 2012) es un claro ejemplo de constelación distintiva. Sin embargo, aun cuando carezcan de un patrón electroclínico característico, deberían considerarse claramente como síndromes epilépticos con causa estructural aquellos casos en los que, por ejemplo, un animal de más de 6 años presenta un cuadro convulsivo de inicio agudo y curso progresivo, con signos clínicos interictales permanentes como alteraciones en las maniobras posturales o en los nervios craneanos. ...
Article
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RESUMEN Las epilepsias y los síndromes epilépticos son muy frecuentes en Medicina Veterinaria. Más del 10% de to-dos los casos neurológicos examinados corresponden a perros convulsivos. Las clasificaciones de las epilepsias y los síndromes epilépticos son imprescindibles para establecer un marco conceptual. Sin embargo, por su alta frecuencia y su diversidad etiológica, es preciso establecer una definición de epilepsia más práctica, que permita tomar decisiones terapéuticas en beneficio del paciente. En este trabajo se analizaron las definiciones sugeridas actualmente en Medicina Humana y, a partir de ellas, se elaboró una propuesta similar aplicable en Medicina Veterinaria. El objetivo de esta propuesta es definir la epilepsia de forma práctica en un contexto clínico operati-vo para facilitar su reconocimiento precoz y posibilitar la elaboración de un protocolo de trabajo que contribuya a la toma de decisiones en el manejo integral de los pacientes con crisis epilépticas. Palabras clave: Epilepsia; Síndromes epilépticos; Definiciones prácticas y operativas. ABSTRACT Epilepsies and epileptic syndromes are very common in Veterinary Medicine. Over 10% of neurologic cases match with convulsive dogs. The classification of epilepsy and epileptic syndromes is essential to establish a conceptual framework. However, considering their high frequency and etiologic diversity, it´s necessary to define epilepsy in a more practical way, which makes it easier to take decisions in benefit of the patient. In this work have been reviewed definitions of Human Medicine, and a similar proposal was drawn up to apply in I.S.S.N.: 0213-5434
... El 12.5% de los gatos con PIF presenta signos neurológicos, que dependen del área involucrada del SNC. En los casos de PIF no efusiva, entre el 25-33% (Schriefl et al. 2008) hasta el 60% de los gatos (Kornegay 1978) tienen manifestaciones neurológicas, mientras que en la forma efusiva las presentan menos del 9% de los individuos afectados (Kornegay 1978). ...
... Intracranial causes of seizures include the following [2,3,9,10,[25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]: ...
Chapter
Seizures occur when bursts of uncontrolled electrical activity translate into motor activity. Seizure activity takes on a variety of presentations, depending upon the patient and the degree to which one or both cerebral hemispheres are involved. Generalized seizures are characterized by whole‐body involvement, collapse, and loss of consciousness. Patients often exhibit extensor rigidity in all four limbs. Limbs also frequently demonstrate paddling behavior. Unconscious behaviors, such as chewing, licking, swallowing, and vocalizing, may emerge during seizure activity. Autonomic signs may also appear. It is not uncommon for patients to lose control over their urinary bladders or bowels. At times, seizures may be difficult to differentiate from syncopal episodes. Thorough history taking may help to distinguish the two. Partial seizures, on the other hand, may resemble dyskinesias. Partial seizures involve one region of one cerebral hemisphere, and may therefore target any part of the body. The neck, trunk, or limbs are most commonly involved. There are many causes of seizures, regardless of whether they are generalized or partial. For ease of consideration, causes of seizure activity may be described as being intra‐ or extracranial. These categories prioritize differentials differently based upon the patient's age. In a pediatric patient, meaning one that is less than one year of age, seizures are most likely due to a developmental defect or traumatic injury. Other common causes of pediatric seizures include hepatic encephalopathy (HE), as from a portosystemic shunt (PSS) or neonatal hypoglycemia. Young adult to middle‐aged patients, on the other hand, are more likely to develop idiopathic epilepsy, as compared to seniors, which are more likely to develop intracranial neoplasia. Most seizures are self‐limiting. However, a fraction of seizures may become protracted, either in terms of their duration or frequency. Cluster seizures occur when the frequency of seizures exceeds two over a 24‐h period. Status epilepticus occurs when either a seizure lasts for more than 5 min, or multiple seizures overlap such that patient recovery time between events is eliminated. Status epilepticus is a medical emergency.
... Seizures in cats make up 0.5%-3.5% of all referrals to veterinary teaching hospitals. [1][2][3] Several anticonvulsant drugs are available for use in cats with daily administration ranging from 1-3 times daily. [4][5][6][7] To achieve greater seizure control, antiseizure medications should be given at the same time every day, often long term. ...
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Background Repeated oral administration of antiepileptic drugs can be challenging for cat owners, resulting in reduced compliance, poor seizure control, and reduced quality of life for cats. Levetiracetam (LEV) has several properties that make it an appealing drug for transdermal application. Objectives The aims were to (1) determine if transdermal LEV, in a lipophilic, liposomic cream vehicle, resulted in serum concentrations above 5 μg/mL; (2) identify clinical adverse effects; and (3) evaluate the concentration of LEV in a lipophilic liposomic cream at set intervals. Animals Six healthy, client‐owned cats weighing ≤5 kg. Methods Prospective clinical trial. Transdermal LEV was applied to the inner pinna at a dosage of 60 mg/kg (400 mg/mL concentration) at home for 6 days. Day 7, cats were hospitalized for blood sample collection for LEV concentration at times 0 (before dose administration), 0.5, 1, 2, 3, and 4 hours after administration. Results Median (range) timed serum concentrations were 16.6 (8.6‐39.6) μg/mL, 16.1 (6.8‐34.4) μg/mL, 15.4 (10.1‐36.7) μg/mL, 17.4 (9.2‐32.7) μg/mL, 15.1 (8.3‐25.9) μg/mL, and 14.8 (11.9‐28.4) μg/mL, respectively. Adverse events were limited to sedation (1/6 cats) and pinna crusting (1/6 cats). The LEV, in the proposed vehicle, retained concentration above 95% at 400 mg/mL up to 5 weeks. Conclusions and Clinical Importance Thrice daily transdermal LEV resulted in median serum concentrations ≥5 μg/mL throughout the sampling period and clinical adverse events were minimal. Transdermal LEV can provide an alternative for cats resistant to administration of other forms of anticonvulsant medication.
... Las convulsiones son uno de los problemas neurológicos más comunes en los gatos, afectando al 1-2% de la población felina (Schriefl et al. 2008); la prevalencia estimada de las convulsiones epilépticas en una población de hospitales de referencia es de 0,5-3,5% (Schwartz-Porsche 1986; ). Las causas son similares a las que afectan a los perros, aunque la incidencia varía entre ambas especies, al igual que las manifestaciones clínicas de la actividad ictal (Moore 2014). ...
Article
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Las convulsiones son uno de los pro-blemas neurológicos más comunes en los gatos, afectando al 1-2% de la población felina (Schriefl et al. 2008); la prevalencia estimada de las convulsiones epilépticas en una población de hospitales de refe-rencia es de 0,5-3,5% (Schwartz-Porsche 1986; Pakozdy et al. 2010). Las causas son similares a las que afectan a los perros, aunque la incidencia varía entre ambas especies, al igual que las manifestaciones clínicas de la actividad ictal (Moore 2014). Clasificación de la epilepsia La epilepsia no es una enfermedad única, sino que incluye un conjunto de trastornos que históricamente han sido dividido en idiopáticos (o primarios) y sintomáticos (o secundarios) (Thomas 2010). La epilepsia sintomática puede resultar de un extenso conjunto de cau-sas incluyendo anomalías metabólicas, neoplasias, infecciones o traumatismos, entre otras. Los síndromes convulsivos crónicos, recurrentes, que no presentan ninguna anormalidad detectable subya-cente ni patologías previas se denominan idiopáticos. En base a los avances en biología molecular la Liga Internacional contra la Epilepsia (de su sigla en inglés, ILAE) actualizó en el año 2010 su terminología en relación a la etiología de las epilepsias que afectan a los seres humanos, agru-pándolas en 3 categorías: (1) genética, indicando que el signo clínico primario son las convulsiones, ocasionadas di-rectamente por un defecto genético; (2) estructural/metabólica, indicando que otra condición distinta, como un proce-so inflamatorio o un traumatismo, puede incrementar el riesgo de desarrollar epi-lepsia; y (3) de causa desconocida, indi-cando que el mecanismo subyacente es aún desconocido y podría resultar de un trastorno genético o de otro trastorno no descrito todavía (Berg et al. 2010; Berg y Scheffer 2011). Además de las conside-raciones etiológicas, la Comisión de Cla-sificación y Terminología de la ILAE (Berg et al. 2010, Berg y Scheffer 2011) creó un nuevo criterio taxonómico para orga-nizar las epilepsias, según su grado de especificidad. De acuerdo a este criterio, el grupo más específico lo constituyen los Síndromes Electroclínicos, que son trastornos específicos, identificables en base a la edad de inicio, las alteraciones electroencefalográficas (EEG), el tipo de crisis y otras características que permiten un diagnóstico específico. La mayoría de estos síndromes tiene un componente genético determinante. Las Constelacio-nes Distintivas son trastornos que reúnen características clínicas suficientes como para permitir un diagnóstico relativamen-te específico. Suelen asociarse a lesiones específicas que los hacen fácilmente re-conocibles. Un ejemplo paradigmático de este grupo sería la epilepsia temporal mesial con esclerosis del hipocampo de los humanos. Las Epilepsias de Causa Estructural-Metabólica son secundarias a una lesión estructural o metabólica pero carecen de un patrón electroclínico ca-racterístico. Finalmente, el grupo de las Epilepsias de Causa Desconocida, anti-guamente denominadas criptogénicas, sería el de menor especificidad sindró-mica, y la comisión estima que en él es-tarían incluidas una tercera parte o más de todas las epilepsias de los humanos (Berg et al.
... Several other studies support this differentiation. 12,13,21 Structural epilepsy is epilepsy that is caused by a structural issue in the cat's brain, this could be from a congenital issue, traumatic head injury or neoplasia. 22 In contrast, idiopathic epilepsy has no discernible structural cause on diagnostic testing. 1 It is possible that the difference in QOL due to age at onset is related to the age at which structural epilepsy is more probable. ...
Article
Background: Epilepsy is the most common neurological condition reported in cats. Characterised by recurrent seizures, treatment involves the administration of anti-epileptic drugs up to multiple times a day. Epilepsy and its associated treatments may impact both cats and their owners. The present study aimed to assess factors associated with quality of life (QOL) in cats with epilepsy and the burden of care in their owners. Methods: An online survey was developed using demographic information and the following validated measures: cat QOL, Zarit burden interview (ZBI) and the cat owner relationship scale (CORS). Regression analysis was conducted using SPSS 26. Results: Responses were completed by 141 owners from 22 countries. QOL was significantly higher in cats with controlled seizures, no adverse effects from medication and epilepsy onset before 5 years of age. ZBI was significantly lower in owners who felt supported by their veterinarian, who were over 55 and had cats with controlled seizures. Higher CORS was significantly correlated with both higher cat QOL and lower owner ZBI. Conclusions: Adequate seizure control and close cat-owner relationships may play an important role in mitigating the impact of epilepsy on cats and their owners. Further research into understanding cat-owner relationships and successfully controlling epilepsy in cats is needed.
Chapter
A wide variety of etiologies may cause different kinds of epileptic seizures in cats. The etiological grouping follows the human classification. Structural epilepsy, idiopathic epilepsy, epilepsy of unknown cause, and reactive epileptic seizures can be classified. Semiological classification is not established in feline medicine, however a subgroup of epileptic cats was recognized in the past decade. The evidence of spontaneous temporal lobe epilepsy in the cat is a relatively new finding in feline epilepsy research and clinical practice. Spontaneously occurring epileptic seizures associated with neuronal necrosis in the hippocampus and piriform lobe, in pet cats, were first described in Switzerland more than 15 years ago, and since then reported many times in different countries. Such cats clinically show complex partial seizures (CPS) with orofacial automatism: salivation, facial twitching, lip smacking, chewing, licking, and swallowing. Likewise, arrest, vegetative, and behavioral signs also occur. MRI data suggest bilateral hippocampal T1 hypointensity and T2 and FLAIR hyperintensity, in some cases. Histopathological findings include varying degrees of neuronal necrosis or sclerosis in the hippocampus. A recent study supports that limbic encephalitis associated with autoantibodies against the voltage-gated potassium channel (VGKC)-complex can be the etiology in some cases. Leucine-rich glioma-inactivated 1 (LGI1) was detected as target of the immune reaction in VGKC antibody positive cats. It should be considered that the cat may serve as an animal model for certain aspects of temporal lobe epilepsy in human medicine.
Article
Objectives The primary objective of this study was to investigate the prevalence of epileptic seizures and of presumed idiopathic epilepsy (PIE, describing epilepsy of unknown origin) in a cohort of British Shorthair (BSH) cats in Sweden. The secondary objective was to describe epileptic seizure characteristics and outcome for cats with PIE. Methods Owners of BSH cats born between 2006 and 2016 and registered with SVERAK (the Swedish Cat Clubs’ National Association) were invited to reply to a questionnaire about their cat’s general health. Owners who indicated that their cat had experienced epileptic seizures were invited to participate in an in-depth telephone interview about the epileptic seizures. The clinical characteristics of epileptic seizures in BSH cats were determined from the results of the interview. Results In this population comprising 1645 BSH cats (representing 28% of registered BSHs), the prevalence of epileptic seizures was 0.9% and for PIE it was 0.7%. BSH cats with PIE presented with infrequent but consistent epileptic seizures. Twenty-seven percent of BSH cats with epileptic seizures had cluster seizures but none presented with status epilepticus. None of the BSH cats was treated with antiepileptic drugs, and none of the owners reported epileptic seizure remission in their cat. Conclusions and relevance The prevalence of PIE in this population of BSH cats was 0.7%. The prevalence of epileptic seizures was 0.9%. In general, PIE in the BSH cat displayed a relatively benign phenotype where progression of epileptic seizures was uncommon.
Article
Epilepsy is a common neurological condition in dogs and cats. Although an increased likelihood of significant brain lesions with age has been identified in neurologically normal dogs with epileptic seizures, the underlying aetiology of epileptic seizures in cats that present with normal physical and neurological examinations remains unknown. In this cross-sectional study, the authors examined MRI findings in a large population of cats with a normal interictal physical and neurological examination. They hypothesised that age would have an impact on the prevalence of detectable lesions. First, following the guidelines for dogs and in accordance with previous studies, the authors divided the cats into three age groups (aged one year or younger, between one and six, and older than six) and calculated the proportion of cats with a detectable lesion on MRI in these groups. In the first group, 3/32 cats (9.4 per cent) had significant MRI abnormalities that were all consistent with congenital malformation; in the second group, only 5/92 (5.4 per cent) MRI scans were abnormal and in the third group, 15/ 65 (23.1 per cent) cats showed abnormal findings that were predominantly lesions of neoplastic origin. Second, to investigate the impact of age further, data were investigated as a continuous variable using receiver operating characteristic analysis. This indicated an optimal cut-off age of five years, above which MRI abnormalities were more likely, with an increase in the odds of a significant structural lesion increasing by 14 per cent per year.
Article
Unter den fokalen Epilepsien der Katze (Felis silvestris catus) sticht die Temporallappenepilepsie (FTLE) durch charakteristische magnetresonanztomographische Veränderungen und das Auftreten orofazialer Automatismen hervor. Histopathologisch finden sich bei der FTLE am häufigsten entzündliche Infiltrate, im Sinne einer oft nekrotisierenden limbischen Enzephalitis (LE) und/oder eine Hippocampussklerose (HS). Serologische und immunhistochemische Untersuchungen bescheinigen der felinen LE (FLE) eine autoimmune Genese. Ihr Auftreten ist nahezu immer mit einer bilateralen HS vergesellschaftet, die sich als totale HS meist auf alle Cornu ammonis (CA)-Segmente erstreckt. Bei anderen strukturellen Hirnläsionen ist die bilaterale Manifestation dagegen eine Seltenheit (<95 %). Erwartungsgemäß ist die Mehrheit der HS-Fälle (76,3 %) mit disruptiven hippokampalen Pathologien vergesellschaftet. Aber auch extrahippokampale Vorderhirnläsionen (26,7 %) und systemische metabolische Ursachen (37,5 %) können bei der epileptischen Katze mit einer HS einhergehen. Während die weite Mehrzahl der Hippocampuspathologien polysegmentale Neuronenverluste aufweist, scheint die HS bei extrahippokampalen Läsionen nur einzelne CA-Segmente einzubeziehen. Die segmentalen Differenzen zwischen humaner und feliner HS (FHS) bedürfen weiterer Abklärung. Dennoch scheint sich die FHS bei FTLE infolge ihrer Assoziation mit refraktären Verläufen als Großtiermodell anzubieten. Gleiches gilt für die FLE im Hinblick auf translationale immunbiologische und -therapeutische Studien. Des Weiteren lassen humananaloge Gyrus-dentatus-Veränderungen auf komplementäre Einblicke hoffen.
Chapter
In regard to epileptic seizures, a common terminology for ictal semiotics and classification is the end goal. Progress made in either the understanding of the underlying pathophysiology or treatment of epileptic seizure disorders, whether in veterinary medicine or human medicine, is easier to identify and apply comparatively. To aid in the clinical discussion of epileptic seizures, the entire process of a seizure has been defined to occur in different elements or phases. This chapter addresses three general classification paradigms. The first is the phenomenological classification of seizures. The second would be the etiological classification of seizures. Finally and most importantly would be the epileptic syndrome the seizure type and etiology fall under.
Article
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The aim of this article was to describe the clinical management of a case with seizure, possibly due to iron deficiency anaemia (IDA) in a kitten. A 38-day-old female European shorthair cat was presented with acute onset of impaired consciousness, seizures and lateralised upper motor neuron tetraparesis. Haematology results showed severe rnicrocytic hypochromic anaemia with marked anisocytosis and thrombocytosis, while a low plasma iron concentration (<0.9 mu mol/L) was the most remarkable biochemical alteration encountered. Iron deficiency anaemia was suspected and oral iron therapy was started together with supportive treatment. The cat responded to therapy and clinical signs started to improve on the second day and returned to normal eight days after referral to the clinic.
Chapter
Seizures and epilepsy have undoubtedly been part of our species from the very bottom of the evolutionary tree. It is estimated that the natural occurrence of seizures in dogs is similar to that of humans, whereas in cats and other species, seizures are considered significantly less common. The earliest description of epilepsy in human beings dates back to about 6000 years ago in a Babylonian text describing epileptic psychoses. The Renaissance marked the beginning of the end of the notion epileptic seizures were brought on by demonic possession, evil spirits, or bad luck. The modern era in the history of epilepsy begins in the late 19th century with the discovery of potassium bromide, more refined animal experimentation, and a distinct correlation between seizure semiology and pathology. Advances in anatomy, physiology, and pathophysiology of the nervous system continued into the early 20th century.
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Zusammenfassung Gegenstand und Ziel Epilepsie gehört auch bei Katzen zu den häufigeren chronischen neurologischen Erkrankungen. Bei der diagnostischen Aufarbeitung spielt die magnetresonanztomographische (weiters: MRT) Untersuchung eine zentrale Rolle. Bei hippocampalen MRT-Veränderungen kann die Frage, ob diese Veränderungen die Ursache oder die Folge der Symptome repräsentieren, oft nicht beantwortet werden.Ziel der Studie war die retrospektive Aufarbeitung der MRT-Befunde einer großen Patientenkohorte an epileptischen Katzen. Material und Methoden Insgesamt wurden 143 Katzen aufgeteilt in 3 Altersgruppen (< 1 Jahr, zw. 1–6 Jahre, > 6 Jahre) in die Studie aufgenommen. Die MRT-Befunde wurden in die folgenden 4 Kategorien aufgeteilt: Unauffällig, extrahippocampale Veränderungen, hippocampale Signaländerungen ohne und mit Kontrastmittelaufnahme. Die Prävalenz und die Auftrittswahrscheinlichkeit der unterschiedlichen MRT-Veränderungen wurden in den Altersgruppen mittels Chi-Quadrat-Test und nominaler Regression geprüft. Ergebnisse Etwa die Hälfte der Katzen (49 %) wies einen unauffälligen MRT-Befund auf. Extrahippocampale Veränderungen wurden in 18 % der Katzen festgestellt. Hippocampale Veränderungen waren bei 33 % der Katzen zu finden. Die hippocampale Sklerose konnte histopathologisch in allen vier MRT-Gruppen (unauffällige MRT, extrahippocampale Veränderungen, hippocampale Signaländerung mit und ohne Kontrastmittelanreicherung) nachgewiesen werden. Schlussfolgerung und klinische Relevanz Bei etwa 50 % der epileptischen Katzen ergibt die Gehirn MRT einen unauffälligen Befund; extrahippocampale Veränderungen sind insbesondere bei älteren Katzen zu erwarten. Die hippocampalen MRT-Veränderungen sind oft ätiologisch nicht zuzuordnen. Weitere Untersuchungen sind erforderlich, um die Bedeutung von hippocampalen Veränderungen zu verstehen.
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Status epilepticus (SE) is one of the most frightening events a pet owner can experience. It is also a significantly worrisome condition for the veterinarian to treat, creating an anxiety level similar to what many feel during the treatment of cardiac and respiratory arrest. Recommendations for treatment continuously change and are updated as the basic understanding of the pathophysiology of SE advances. Similar to humans, SE is more likely to occur in dogs and cats with structural brain disease or reactive causes of seizures. Emergency management of seizures should follow some general guidelines. It is important to consider all necessary steps as proceeding as much at the same time as possible. One of the most important elements of a successful outcome in the treatment of SE is the maintenance of normal blood pressure and adequate fluid resuscitation along with reduction of Intracranial pressure (ICP), if it is elevated.
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Practical relevance: Seizures are one of the most common neurological problems recognized in cats, affecting approximately 1-3% of the general population. Treatment options and prognosis are closely related to the underlying cause, so it is important that veterinarians are familiar with the diagnostic approach to cats with seizures and options for medical management. Series outline: This is the second of a two-part article series that reviews the diagnosis and treatment of seizures in cats. Part 2 describes chronic medical treatment options and prognosis for cats with recurrent seizures, and acute treatment of status epilepticus. Audience: This review of recurrent seizures in cats is intended for all veterinarians who are facing the challenges of seizure diagnosis and management in the feline patient. Evidence base: Recommendations for diagnosis and management of feline seizure disorders have historically been extrapolated from the canine and human literature. The information and guidance provided in this two-part series is based on a review of the recent published literature addressing seizure disorders and antiepileptic treatment in cats, as well as the authors' clinical experience.
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Survival of cats with epilepsy of unknown cause (EUC) has not been reported. Seizure semiology and its relationship to treatment outcome and survival was studied in a population of 76 cats. A questionnaire for seizure semiology was developed based on experimental data. Seizure semiology was characterised by owner interviews at least one year after discharge. Seizures were classified as (1) primary generalised and (2) focal without and (3) with secondary generalisation. Median age at seizure onset was four (range 0.3–18) years. One-third of cats with EUC presented with primary generalised seizures and 78 per cent of those with initially focal seizures progressed to secondary generalised seizures. Clinical signs of generalised seizures included sudden onset of loss of consciousness and tonic-clonic seizures, while cats with focal seizures had unilateral signs. Antiepileptic drug (AED) therapy was initiated in 62 cats. Complete remission rate was 42 per cent and the median survival time was 3.2 (range 1–11) years with or without AED, and 91 per cent were still alive at the time of interview. Neither semiology nor seizure type predicted survival, response to treatment and outcome in cats with EUC. A seizure-free status of more than 12 months was observed in 79 per cent of cats without AED.
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Practical relevance: Seizures are one of the most common neurologic problems recognized in cats, affecting approximately 1-3% of the general population. Treatment options and prognosis are closely related to the underlying cause, so it is important that veterinarians are familiar with the diagnostic approach to cats with seizures and options for medical management. Series outline: This is the first of a two-part article series that reviews the diagnosis and treatment of seizures in cats. Part 1 outlines the classification and terminology used to describe epilepsy and epileptic seizures in cats, and discusses some of the most common and unique causes of recurrent seizures in cats. The diagnostic approach to cats with recurrent seizures is addressed, as are criteria for the diagnosis of idiopathic epilepsy. Audience: This review of recurrent seizures in cats is intended for all veterinarians who are facing the challenges of seizure diagnosis and management in the feline patient. Evidence base: Recommendations for diagnosis and management of feline seizure disorders have historically been extrapolated from the canine and human literature. The information and guidance provided in this two-part series is based on a review of the recent published literature addressing seizure disorders and antiepileptic treatment in cats, as well as the authors' clinical experience.
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OBJECTIVE To identify seizure etiologic classification for cats that developed seizures at < 12 months of age and describe the long-term outcome of affected cats. DESIGN Retrospective cohort study. ANIMALS 15 client-owned cats with seizures that began at < 12 months of age. PROCEDURES Information on each cat was obtained from the medical records, veterinarians, and owners. Inclusion required an onset of seizures before 12 months of age and a complete medical record, including a final diagnosis. RESULTS 7 of the 15 cats had structural epilepsy, 4 had idiopathic epilepsy, and 4 had reactive seizures. Median age at seizure onset was 27 weeks (range, 0.4 to 41 weeks). Cluster seizures were reported in 6 cats, and status epilepticus was reported in 2. Age at the onset of seizures, presence of cluster seizures, and seizure semiology (ie, generalized vs focal seizures) were not significantly associated with seizure etiologic classification. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that cats that developed seizures at < 12 months of age were more likely to have structural epilepsy than idiopathic epilepsy or reactive seizures. Therefore, advanced diagnostic imaging is recommended in cats with juvenile-onset seizures if metabolic and toxic causes are excluded.
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Idiopathic brain inflammation such as granulomatous meningoencephalitis is uncommon in cats. The brain can be subdivided into four major anatomic categories: prosencephalon, midbrain, medulla, and cerebellum. Rabies is a fatal zoonotic disease. Rabies will present as progressive neurologic illness of less than two weeks’ duration, although clinical deterioration will often take place over only a few days. Hepatic encephalopathy should be suspected in neurologically abnormal cats with icterus, a history of prolonged anorexia, and/or blood‐work findings compatible with severe liver disease. Thiamine deficiency is seen in cats receiving overly cooked diets, some commercial canned food diets, pure raw‐fish diets, or cats with prolonged anorexia and/or malabsorptive enteropathies. Head trauma is common particularly in cats with outdoor access. Head trauma is often a component of polytrauma and the initial focus in these patients should be toward normalizing circulation, the airway, and ventilation.
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To investigate emergency clinicians’ comfort level in assessing neurological emergencies and to identify opportunities to foster enhanced training of clinical neurology in the emergency room. Internet‐based survey. University teaching hospitals and private referral centers. One hundred and ninety‐two emergency and critical care specialists and resident trainees (ECC) and 104 neurology specialists and resident trainees (NEUR) in clinical practice. An internet‐based survey was distributed via veterinary professional organizations’ listserves and message boards and responses were collected between March and April 2020. ECC completed a survey evaluating stress levels associated with neurological emergencies, confidence with neurological examinations, and neuroanatomical localization. NEUR completed a similar survey to report their perception of their ECC colleagues’ confidence in the assessment of neurological cases. Chi‐square and Mann–Whitney U‐tests were used to compare categorical responses and confidence scores between groups. P < 0.002 was considered significant. Fifty‐two percent of ECC found neurological emergencies slightly challenging, whereas 85% of NEUR found them moderately to extremely challenging for ECC (P < 0.0001). ECC's median self‐reported confidence score in performing a neurologic examination on a scale of 0–100 was 75 (interquartile range [IQR], 27), while NEUR reported a median ECC confidence of 44 (IQR, 25; P < 0.0001). Median self‐reported ECC confidence in localizing intracranial, spinal, and neuromuscular disease was 67 (IQR, 40), 88 (IQR, 21), and 60 (IQR, 37), respectively, which was significantly higher than median NEUR‐reported ECC confidence of 35 (IQR, 38), 51 (IQR, 31), and 18 (IQR, 20), respectively (all P < 0.0001). Following case transfer, 34% of ECC received NEUR feedback in >75% of cases. Noticeable discrepancies between ECC and NEUR perceptions of ECC clinical confidence were seen, while no firm evidence of neurophobia could be inferred. Improvements in interdepartmental communication and teaching of clinical neurology may be warranted.
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Objectives The study objective was to investigate the prevalence and clinical characteristics of phenobarbitone-associated adverse effects in epileptic cats. Methods The medical records of two veterinary referral clinics from 2007 to 2017 were searched for cats fulfilling the inclusion criteria of a diagnosis of epilepsy, treatment with phenobarbitone and available follow-up information on the occurrence of adverse effects. Follow-up information was obtained from the medical records of the primary veterinarian and referral institutions and a questionnaire completed by the cats’ owners. Results Seventy-seven cats met the inclusion criteria. Fifty-eight were affected by idiopathic epilepsy and 19 by structural epilepsy. One or more of the following adverse effects were reported in 47% of the cats: sedation (89%); ataxia (53%); polyphagia (22%); polydipsia (6%); polyuria (6%); and anorexia (6%). Logistic regression analyses revealed significant associations between adverse effect occurrence and both phenobarbitone starting dosage and administration of a second antiepileptic drug (AED). For each 1 mg/kg q12h increment of phenobarbitone, the likelihood of adverse effects increased 3.1 times. When a second AED was used, the likelihood of adverse effects increased 3.2 times. No association was identified between epilepsy aetiology and adverse effect occurrence. An idiosyncratic adverse effect, characterised by severe neutropenia and granulocytic hypoplasia, was diagnosed in one cat. This resolved following phenobarbitone discontinuation. Conclusions and relevance The prevalence of phenobarbitone-associated adverse effects was 47%. Sedation and ataxia were most common. These are type A adverse effects and are predictable from phenobarbitone’s known pharmacological properties. In the majority of cases, adverse effects occurred within the first month of treatment and were transient. Idiosyncratic (type B) adverse effects, which were not anticipated given the known properties of the drug, occurred in one cat. Increased phenobarbitone starting dosage and the addition of a second AED were significantly associated with the occurrence of adverse effects.
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Objectives: The aim of this study was to determine whether transient postictal hyperammonaemia exists in cats. Methods: The medical records of all feline patients that presented at a Swedish veterinary hospital between 2008 and 2018 were retrospectively reviewed to find those that had a recent or ongoing epileptic seizure. To qualify for inclusion, the medical record had to include information on at least one ammonia value taken in close proximity to, or during, an active seizure, the cat must have exceeded the normal upper limit of blood ammonia concentration on initial testing (reference interval 0-95 μmol/l), and there needed to be a follow-up ammonia value available within a maximum of 3 days. Results: Five cats were included in the study, and they had blood ammonia concentrations on initial testing ranging from 146 to 195 µmol/l. They were all retested within a period of 2 h to 3 days of the original reading. All five cats had a spontaneous decrease in ammonia levels without any specific treatment for hyperammonaemia. Conclusions and relevance: Pursuant to the findings of this retrospective study, transient hyperammonaemia may be noted after epileptic seizure in cats. Consequently, a differential diagnostic list in feline patients with hyperammonaemia could, depending on the context, include non-hepatic-related pathologies, such as epileptic seizures.
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This is a chapter in "VIN Cyclopedia of diseases" that describes the aetiology, pathophysiology, diagnosis and treatment of status epilepticus in cats.
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World Health Organization data suggest that neurological disorders are an important and growing cause of morbidity. One of the most common neurological disorder affecting people is epilepsy. Many companion animal neurological diseases share epidemiologic, pathophysiologic and clinical features with their human counterparts. In companion animals, affected species are mostly dogs, cats and rabbits. Seizure is defined as the clinical manifestation of abnormal electrical activity in the brain. Epilepsy is a brain disease characterized by the psychological, cognitive, social and environmental consequences of seizures. The epileptic seizures are recurrent events characterized by behavioral alterations that reflect the underlying neural mechanisms of the disease. In most cases, the disease can be diagnosed by anamnesis or observing the seizure. There are many reviews and researches about epilepsy and epileptic seizures in companion animals such as dogs and cats but not in rabbits. There are several causes of epilepsy in rabbits including viral, bacterial, parasitic, metabolic, respiratory, cardiovascular, nutritional, toxic, traumatic, enviromental and non-epileptic causes. Rabbits can be considered suitable for seizure and epilepsy investigations due to their recurrent seizures with low risk of death. As mentioned, there are several causes of epilepsy in rabbits but still to elucidate the exact mechanism of epilepsy and epileptic seizures in rabbits more studies need to be carried out. Despite the advances in the disease management, epilepsy is still an important cause of disability and mortality in both humans and companion animals. As tonic-clonic seizures with brainstem origin mostly affect children, epileptic seizures in rabbits may be a good model for further studies. Key words: Brain disease, epilepsy, neural disturbances, behavioral alterations, rabbit, seizure.
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Objectives: Phenobarbital (PB) is the most common antiseizure drug (ASD) used for the management of feline epilepsy. In dogs, PB is known to cause serum liver enzyme induction and hepatotoxicity, especially after administration long term or in high concentrations. In cats, insufficient evidence is available to draw similar conclusions. The aim of this study was to evaluate the effect of PB administration on the serum biochemistry profile of epileptic cats. As an additional objective, other adverse effects arising, related to PB treatment, were recorded. Methods: Medical records of four veterinary centres were retrospectively reviewed for epileptic cats receiving PB treatment. Cats were included if they had a diagnosis of idiopathic epilepsy or structural epilepsy; a normal baseline serum biochemistry profile; at least one follow-up serum biochemistry profile; no concurrent disease or had not received medication that could possibly influence liver function or lead to serum liver enzyme induction. Alkaline phosphatase, alanine aminotransferase (ALT), aspartate transaminase and gamma-glutamyl transferase activities, and total bilirubin, bile acids, glucose, albumin, total protein, urea and creatinine concentrations before and during PB administration were recorded. PB serum concentration was also recorded, when available. Results: Thirty-three cats (24 males, nine females) with a median age of 3 years (range 2 months to 12 years) met the inclusion criteria. Idiopathic or structural epilepsy was diagnosed in 25 (76%) and eight (24%) cats, respectively. The follow-up period ranged from 9 to 62 months. This study found an increase in ALT in three cats, possibly related to a PB serum concentration >30 µg/ml. No statistically significant increase in serum liver enzymes or other evaluated biochemistry parameters was found by comparing pre- and post-treatment parameters. Conclusions and relevance: PB administration did not result in hepatic enzyme induction or other biochemical abnormalities in cats. This strengthens the safety profile of PB as an ASD in cats.
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Literature is sparse about seizures in adult horses and this affection often carries a poor prognosis for further riding or athletic use. The authors present a case of an adult horse showing recurrent focal seizures and neurological deficits indicative of central blindness occurring during an episode of colic which was resolved surgically. Clinical signs occurred soon after an episode of colic, then resolved by laparotomy with an uneventful general anaesthesia. The investigations undertaken to find the cause of the seizures concluded finally a tentative diagnosis of a cortical lesion associated with amaurosis due to possible brain hypoxia and/or trauma. The outcome of the presented case was satisfactory, as four months later on a control examination no further seizures had been reported, most neurological deficits had disappeared and vision had at least partially been restored.
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Six cats with chronic progressive neurologic signs of ataxia, paresis, tremors, pupillary abnormalities and seizures had polioencephalomyelitis of probable viral origin. Lesions were most severe in the spinal cord. The uniformity in distribution and nature of the lesions in all six cats strongly suggested a common cause. The condition was compared with other viral infections of known and unknown cause.
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Phenobarbital was administered orally to seven healthy cats at a dose of 5 mg/kg once a day for 21 days. Serum phenobarbital concentrations were determined using a commercial immunoassay technique. A one-compartment model was used to describe the final elimination curve. The elimination half-life (t1/2 b) after the final day of treatment was 43.3 +/- 2.92 h. The large apparent volume of distribution of 695.0 +/- 43.9 mL/kg suggests that the drug was widely distributed within the body. The t1/2 b following multiple oral administration was significantly shorter than previously reported for a single oral dose of phenobarbital in the cat. Analysis of pharmacokinetic results after days 1 and 21 of treatment suggested that the elimination kinetics of phenobarbital did not change significantly with multiple oral administration. It appears that differences in elimination kinetics can exist between populations of cats. These differences emphasize the need for individual monitoring of cats receiving phenobarbital.
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In 10 of 16 domestic cats with spontaneous non-suppurative encephalomyelitis, lesions were multifocal but relatively few and were considered nonspecific as to cause, although viral agents could not be excluded. Six cats had polioencephalomyelitis or polioencephalitis suggestive of viral infection. The clinical and morphological features are compared with those of previous reports of feline encephalitis possibly of viral origin. Some previously reported epidemiological and serological surveys suggest a possible role for arboviruses.
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The purpose of this report is to present the clinical, cerebrospinal fluid (CSF) and histological data from 27 cats with inflammatory disease of the central nervous system (CNS). The cats were part of a study of 61 cats admitted to two university clinics over an eight-year period because of signs of CNS disease. The most frequent diseases were feline infectious peritonitis (FIP) (12/27) and suspected viral disease other than FIP (10/27). Typical CSF findings in cats with FIP were a protein concentration of greater than 2 g/L (200 mg/dL) and a white cell count of over 100 cells/microL, which consisted predominantly of neutrophils. In contrast, the CSF of cats with suspected viral disease had a protein concentration of less than 1 g/L (100 mg/dL) and a total white cell count of less than 50 cells/microL. In general, cats with FIP or suspected viral disease were less than four years of age. Neurological signs were usually multifocal in cats with FIP, but focal in cats with suspected viral disease. The CSF findings were variable in five other inflammatory diseases represented. Two cats with protozoan infection had normal CSF total cell counts but abnormal differential counts. The CSF findings were invaluable in differentiating FIP from other causes of inflammatory CNS disease.
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Ictal bradycardia is rare and its localising value is debated. Bradyarrhythmias are, however, important because of their potential connection to sudden death and ability to affect clinical seizure manifestations. Cerebral hypoperfusion induces loss of consciousness, at times with myoclonic jerks, whose clinical differentiation from a generalised convulsive seizure may prove difficult. Two invasive and five surface monitored seizures recorded over two years in a 51 year old woman with post-traumatic epilepsy characterised by seizure-triggered asystole were analysed. All seven seizures showed left temporal onset. Both intracranially recorded events started in the left anterior hippocampus/amygdala, spreading to the contralateral hippocampus in 35 and 25 seconds. Within 10 seconds an electrocardiogram showed asystole lasting 21 and 28 seconds, associated with suppression of recorded cerebral electrical activity, except a polyspike suppression pattern remaining in the hippocampi. Clinically, the patient, concomitantly with the cerebral suppression, developed myoclonic twitches of the limbs. A dual chamber cardiac pacemaker was implanted; at 11 months follow up, the patient has experienced only infrequent partial seizures, with none involving falls or shaking. Left temporal lobe seizures produced convulsive syncope initiated by ictal asystole. These observations suggest that intertemporal spread is necessary, though not sufficient, to produce bradycardia and asystole. Furthermore, pacemakers may decrease seizure severity, as well as potentially protect against malignant bradyarrhythmias.
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The clinical, hemodynamic, and pathologic features of hypertensive encephalopathy in two cats with reduced renal mass are described. The cats developed a progressive syndrome of lethargy, ataxia, blindness, stupor, and seizures following an abrupt increase in blood pressure associated with a surgical reduction in renal mass. The cats had severe gross brain edema, evidenced by cerebellar changes of caudal coning and cranial displacement over the corpora quadrigemina and cerebral changes of widening and flattening of the gyri. Histologically, interstitial edema was most pronounced in the cerebral white matter. Hypertensive vascular lesions were present as hyaline arteriolosclerosis in one cat and hyperplastic arteriolosclerosis in the other. Rare foci of parenchymal microhemorrhages and necrosis were also observed. Systemic hypertension (especially severe or rapidly developing) accompanied by neurologic signs and the pathologic findings of diffuse brain edema with cerebral arteriolosclerosis are consistent with an etiologic diagnosis of hypertensive encephalopathy.
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Experimental prolonged febrile seizures (FS) lead to structural and molecular changes that promote hippocampal hyperexcitability and reduce seizure threshold to further convulsants. However, whether these seizures provoke later-onset epilepsy, as has been suspected in humans, has remained unclear. Previously, intermittent EEGs with behavioural observations for motor seizures failed to demonstrate spontaneous seizures in adult rats subjected to experimental prolonged FS during infancy. Because limbic seizures may be behaviourally subtle, here we determined the presence of spontaneous limbic seizures using chronic video monitoring with concurrent hippocampal and cortical EEGs, in adult rats (starting around 3 months of age) that had sustained experimental FS on postnatal day 10. These subjects were compared with groups that had undergone hyperthermia but in whom seizures had been prevented (hyperthermic controls), as well as with normothermic controls. Only events that fulfilled both EEG and behavioural criteria, i.e. electro-clinical events, were considered spontaneous seizures. EEGs (over 400 recorded hours) were normal in all normothermic and hyperthermic control rats, and none of these animals developed spontaneous seizures. In contrast, prolonged early-life FS evoked spontaneous electro-clinical seizures in 6 out of 17 experimental rats (35.2%). These seizures consisted of sudden freezing (altered consciousness) and typical limbic automatisms that were coupled with polyspike/sharp-wave trains with increasing amplitude and slowing frequency on EEG. In addition, interictal epileptiform discharges were recorded in 15 (88.2%) of the experimental FS group and in none of the controls. The large majority of hippocampally-recorded seizures were heralded by diminished amplitude of cortical EEG, that commenced half a minute prior to the hippocampal ictus and persisted after seizure termination. This suggests a substantial perturbation of normal cortical neuronal activity by these limbic spontaneous seizures. In summary, prolonged experimental FS lead to later-onset limbic (temporal lobe) epilepsy in a significant proportion of rats, and to interictal epileptifom EEG abnormalities in most others, and thus represent a model that may be useful to study the relationship between FS and human temporal lobe epilepsy.
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Although pathophysiologically distinct, syncope and seizures share clinical characteristics which may make diagnosis difficult. Adding to diagnostic complexity are the facts that seizures and syncope may coexist in the same patient, syncope may be associated with seizure-like motor manifestations, and seizures may be complicated by cardiac arrhythmia and syncope. Combined EEG/ECG telemetry is sometimes necessary to establish the correct diagnosis. These techniques also provide an opportunity to study the role of certain cortical regions in the modulation of cardiac function. There is an increasing understanding of the central autonomic pathways involved in the genesis of the cardiovascular changes that occur during epileptic seizures. This article reviews the use of EEG/ECG telemetry in the evaluation of syncope and seizures, and the neuroanatomic circuitry involved in the production of the cardiovascular manifestations of seizures.
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In approximately two-thirds of the epileptic cats in this article, an idiopathic epilepsy had to be assumed. It began between six and 36 months of age with a single seizure, which usually occurred during rest or sleep. Symptomatic epilepsy was frequently observed during the first two years of life and in old age, beginning frequently with multiple seizures or status epilepticus and less often during sleep or rest. In both types, grand mal seizures are predominant. Seizure clusters or status epilepticus caused extensive neuron necroses and scleroses in Ammon's horn. Diazepana and phenobarbital are antiepileptics of first choice for the cat; primidone and phenytoin are less suitable.
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SEIZURES are the one of the most common presentations in the neurological feline patient and can be a daunting prospect for the veterinary clinician. The list of possible differential diagnoses is huge and demands a careful and systematic diagnostic approach. This article steers the practitioner through the work-up and provides guidance on the provision and monitoring of antiepileptic drug therapy in cats.
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Hypoglycemia can cause brain dysfunction, brain injury, and death. The present study seeks to broaden current information regarding mechanisms of hypoglycemic brain injury by investigating a novel etiology. The cat's high resistance to brain injury from hypoglycemia suggested that additional influences such as respiratory depression might play a facilitating role. Three groups of cats were exposed to fasting and insulin-induced hypoglycemia (HG; n = 6), euglycemic respiratory depression (RD; n = 5), and combined hypoglycemic respiratory depression (HG/RD; n = 10). The HG animals were maintained at <1.5 mmol (mean 1 mmol) serum glucose concentration for 2 to 6.6 hours. The respiratory depression was associated with Pao2 and Paco2 values of ~50 mm Hg for 1 hour and of ~35 and ~75 mm Hg, respectively, for the second hour. Magnetic resonance diffusion-weighted imaging estimated brain energy state before, during, and after hypoglycemia. The hypoglycemic respiratory depression exposures were terminated either to euglycemia (n = 4) or to hyperglycemia (n = 6). Brain injury was assessed after 5 to 7 days of survival. Cats exposed to hypoglycemia alone maintained unchanged diffusion coefficients; that is, they lacked evidence of brain energy failure and all six remained brain-intact. Only 1 of 5 euglycemic RD but 10 of 10 HG/RD cats developed brain damage (HG and RD vs. HG/RD, P < 0.01). This difference in brain injury rates suggests injury potentiation by hypoglycemia and respiratory depression acting together. Three injury patterns emerged, including activation of microglia, selective neuronal necrosis, and laminar cortical necrosis. Widespread activation of microglia suggesting damage to neuronal cell processes affected all damaged brains. Selective neuronal necrosis affecting the cerebral cortex, hippocampus, and basal ganglia was observed in all but one case. Instances of laminar cortical necrosis were limited to cats exposed to hypoglycemic respiratory depression treated with hyperglycemia. Thus, treatment with hyperglycemia compared with euglycemia after hypoglycemic respiratory depression exposures significantly increased the brain injury scores (24 ± 6 vs. 13 ± 2 points; P < 0.05). This new experimental hypoglycemia model's contribution lies in recognizing additional factors that critically define the occurrence of hypoglycemic brain injury.Keywords: Hypoglycemic encephalopathy; Hypoxia/hypercarbia; Insulin/fasting; Diffusion-weighted magnetic resonance imaging; Hyperglycemic treatment
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Epilepsy carries a risk of premature mortality, but little is known about life expectancy in people with the condition. The UK National General Practice Study of Epilepsy is a prospective, population-based study of people with newly diagnosed epilepsy. A cohort of 564 patients with definite epilepsy has been followed for nearly 15 years and there have been 177 deaths. These data have been used to estimate life expectancy of people in this cohort by employing a parametric survival model based on the Weibull distribution. Life expectancy in people with epilepsy was estimated as a function of age at, and time from, diagnosis according to two broad aetiological groups. These estimates were then compared with life expectancy in people of the same age and sex in the general population. Reduction in life expectancy can be up to 2 years for people with a diagnosis of idiopathic/cryptogenic epilepsy, and the reduction can be up to 10 years in people with symptomatic epilepsy. Reductions in life expectancy are highest at the time of diagnosis and diminish with time. Our model provides broad estimates, but it appears that the higher mortality rates in people with newly diagnosed epilepsy translate into decreased life expectancy.
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On initial evaluation for onset of seizure disorders at nonreferral veterinary practices, 50 previously healthy dogs were enrolled in a study to determine the probability of identifying a specific cause for the seizures. Treatment was not administered prior to entry of dogs in the study. On the basis of antemortem and postmortem test results, 22 dogs (44%) were classified as having primary epileptic seizures (PES; idiopathic or without identifiable cause), 23 (46%) had secondary epileptic seizures (SES; identifiable intracranial cause), and 5 (10%) had reactive epileptic seizures (RES; metabolic or transient noxious cause). Forty-one dogs (82%) had 2 or more seizures before evaluation, with 37 (90%) of these dogs classified as having epilepsy on the basis of an underlying chronic brain disorder. For these 41 dogs, 17 (41%) had PES, 20 (49%) had SES, and 4 (10%) had RES. Among the 9 dogs (18%) with nonrecurring seizures, 5 had PES, 3 had SES, and 1 had RES. Generalized seizures were the most common first-observed seizure type associated with all etiologic classifications in all dogs with recurring and nonrecurring seizures. Diagnosis of SES was statistically more probable when the dog was less than 1 or more than 7 years old at the first seizure, when the first seizure was a partial seizure, or when the first seizure occurred between midnight and 8 AM. A diagnosis of RES was statistically more probable only when the interval between the first and second seizure was brief (< or = 4 weeks).(ABSTRACT TRUNCATED AT 250 WORDS)
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To investigate causes of seizure disorders in cats. Case series. 30 cats referred to the Ontario Veterinary College for recurrent seizures. Signalment and seizure pattern were evaluated. Diagnostic procedures included physical, neurologic, and fundic examinations; CBC; serum biochemical analyses, including determination of pre- and postprandial bile acid concentrations; urinalysis; serologic assays for FeLV and feline immunodeficiency virus, feline infectious peritonitis, and Toxoplasma gondii, magnetic resonance imaging of the brain; CSF analysis; and neuropathologic examination of euthanatized cats and of surgical biopsy specimens. All cats were found to have structural brain diseases; nonsuppurative meningoencephalitis of unknown cause was found in 14 cats, feline ischemic encephalopathy in 6, meningioma in 2, polycythemia vera with secondary brain lesions in 2, posttraumatic epilepsy in 1, and cerebral abscess in 1. A definitive diagnosis could not be reached in 4 cats. The most common cause of seizures in cats is structural brain disease. Structural brain lesions often can be detected on the basis of seizure pattern and results of neurologic examination. Cerebrospinal fluid analysis and brain imaging are essential to determine the cause of these lesions. Causes of seizures found in the cats of this study differ from those reported to be the most common. Nonsuppurative meningoencephalitis of unknown origin appears to be a frequent cause of neurologic disorders in cats, including seizure disorders. Feline ischemic encephalopathy appears to exist in a milder form than the classic disease and may be a common cause of seizures in cats.
Article
Electroencephalographic (EEG) findings in syncope are reviewed. There are four major categories of syncope: neurally mediated (neurocardiogenic), neurologic, decreased cardiac output, and orthostatic hypotension. However, regardless of cause, whether the syncope is due to a vasovagal effect, a cardiac arrhythmia, an epileptic seizure, or hypotension, EEG findings are similar and reflect cerebral hypoperfusion. Initially there may be a slowing of background rhythms. This is followed by high amplitude delta activity, maximal anteriorly. If the hypoperfusion persists there is subsequent flattening of the EEG. The EEG returns to normal in the reverse sequence. In cases with severe and prolonged ischemia, convulsive syncope may occur at the time of the EEG flattening. Although not an epileptic phenomena, clinically this is often mistaken for epilepsy. Conversely, epileptic disorders, such as the ictal bradycardia syndrome, may occasionally mimic syncope. Therefore, in patients in whom EEGs are performed for the evaluation of an episode of loss of consciousness, simultaneous ECG should be used.
Article
Survey data were collected on the incidence of epileptic seizures in 997 Belgian tervuerens. The heritability of this disorder was estimated as 0.77 (with a 95 per cent confidence interval spanning from 0.65 to 0.88) using a Bayesian analysis in an ordered categorical threshold model. Single locus models do not appear adequate as an explanation for this inherited seizure disorder. The high heritability estimate suggests that breeders can wage a successful battle against this disorder by breeding unaffected individuals, particularly those from families with no history of seizures.
Article
The diagnosis and management of seizures in the cat require an understanding of the more common diseases that predispose to feline epilepsy. Feline seizures may occur secondary to intracranial or extracranial disease. Intracranial causes include inflammatory, neoplastic, vascular, and traumatic disorders. Extracranial causes include various metabolic and toxic insults. Previous brain insults that are no longer active may leave "seizure foci." Idiopathic epilepsy is uncommon in the cat relative to the dog but should be considered if no cause can be found. Regardless of the etiology, ictal events in cats can manifest themselves in multiple forms and levels of severity. Therapy should be directed at controlling seizure frequency and treating the underlying cause. An aggressive diagnostic and therapeutic approach to feline epilepsy may improve prognosis and lead to a favorable outcome.
Article
Epilepsy is a disorder of recurrent seizures that are neural in origin. Partial seizures are usually due to a structural cerebrocortical lesion and may be simple or complex. Brain injuries may alter inherent neuronal properties and neuronal circuits and lead to recurrent excitatory activity. Potentiation of excitatory synapses and depression of inhibitory synapses are probable critical events in epileptogenesis. The pathogenic factors underlying primary or idiopathic generalized seizures are not as well understood. A more diffuse or multifocal state of neuronal excitability may be the result of early congenital events that are magnified over time. The progression of subclinical neuronal excitatory activity to a clinical seizure may relate directly to the phenomenon of cortical plasticity.
Article
To report clinical findings, treatments, and outcomes of dogs admitted to the hospital for status epilepticus or cluster seizures and evaluate factors associated with outcome. Retrospective study. 156 dogs admitted for status epilepticus or cluster seizures. Medical records were reviewed for seizure and medication history, diagnostic test results, types of treatment, hospitalization costs, and outcome of hospital visits. Dogs were admitted for seizures on 194 occasions. Of 194 admissions, 128 (66%), 2 (1%), 32 (16.5%), 2 (1%), and 30 (15.5%) were of dogs with a history of clusters of generalized seizures, clusters of partial complex seizures, convulsive status epilepticus, partial status epilepticus, and > 1 type of seizure, respectively. Underlying causes of seizures were primary epilepsy (26.8%; 52/194), secondary epilepsy (35.1%; 68), reactive epileptic seizures (6.7%; 13), primary or secondary epilepsy with low serum antiepileptic drug concentrations (5.7%; 11), and undetermined (25.8%; 50). One hundred and eighty-six hospital visits resulted in admission to the intensive care unit (ICU). Treatments with continuous i.v. infusions of diazepam or phenobarbital were initiated during 66.8% (124/186) and 18.7% (35) of ICU hospital stays for 22.3 +/- 16.1 hours (mean +/- SD) and 21.9 +/- 15.4 hours, respectively. Of 194 admissions, 74.7% (145) resulted in discharge from the hospital, 2.1% (4) in death, and 23.2% (45) in euthanasia. A poor outcome (death or euthanasia) was significantly associated with granulomatous meningoencephalitis, loss of seizure control after 6 hours of hospitalization, and the development of partial status epilepticus. Granulomatous meningoencephalitis, loss of seizure control after 6 hours of hospitalization, or the development of partial status epilepticus may indicate a poor prognosis for dogs with seizures.
Article
The clinical records of 38 cats (1985-1995) with a neuropathologically confirmed diagnosis of necrosis of the hippocampus and occasionally the lobus piriformis were evaluated retrospectively. There was no sex or breed predisposition. Most cats were between 1 and 6 years of age (mean age 35 months) and had either generalized or complex-partial seizures of acute onset and rapid progression. The seizures had a tendency to become recurrent and to present as clusters or even status epilepticus later in the course of the disease. Fourteen cats died spontaneously, and 24 were euthanized. Histopathologic examination revealed bilateral lesions restricted to the hippocampus and occasionally the lobus piriformis. The lesions seemed to reflect different stages of the disease and consisted of acute neuronal degeneration to complete malacia, affecting mainly the layer of the large pyramidal cells but sometimes also the neurons of the dentate gyrus and the piriform lobe. The clinical, neuropathologic, and epidemiologic findings suggest that the seizures in these cats were triggered by primary structural brain damage, perhaps resulting from excitotoxicity. The cause remains unknown, but epidemiologic analysis suggests an environmental factor, probably a toxin.
Article
A diagnostic scheme for epileptic seizures and epilepsies with five levels or Axes is proposed (1, ictal semiology; 2, seizure type[s]; 3, epilepsy syndrome; 4, etiology, and 5, resulting impairment). A standardized Glossary of Descriptive Terminology is used for the description of the ictal semiology and the description of seizure types is derived from a list of accepted seizure types constructed by the Task Force. If possible, the syndromic diagnosis follows according to a list of accepted epilepsy syndromes as well as syndromes in development provided by the Task Force. Regarding etiology another list or classification of diseases frequently associated with epileptic seizures or syndromes is provided. The (optional) designation of a resulting impairment will be derived from the WHO International Classification of Functioning and Disability. In addition, the use of some diagnostic terms is discouraged or they are replaced by others (e.g. simple and complex partial seizures", partial" and localization related syndromes", convulsive" and convulsion"), the meaning of other terms is clarified (cryptogenic" = probably symptomatic") and some new concepts are proposed (e.g. epileptic disease" with a single, specific etiology or epileptic encephalopathy" as condition, in which the epileptic processes themselves lead to cerebral dysfunction). It is emphasized that this proposal is not a new classification of seizures and epilepsies or epilepsy syndromes. The proposed scheme should lead to an updated and uniformed use of the diagnostic vocabulary in the preparation of a future new classification or rather multiple classifications for different purposes (e.g. for teaching and research purposes or clinical trials). It is flexible and will be periodically changed and updated in the future as needed.
Article
To identify risk factors for episodes of status epilepticus (SE) in dogs with idiopathic epilepsy and determine how SE affects long-term outcome and survival time. Retrospective study. 32 dogs with idiopathic epilepsy. Information on signalment, seizure onset, initiation of treatment, anticonvulsants administered, number of episodes of SE, overall seizure control, and long-term outcome was obtained from medical records and through telephone interviews. Differences between dogs that did and did not have episodes of SE were evaluated statistically. 19 (59%) dogs had 1 or more episodes of SE. Body weight was the only variable significantly different between dogs that did and did not have episodes of SE. Thirteen dogs (9 that did not have episodes of SE and 4 that did) were still alive at the time of the study and were > or = 10 years old. Six of the 19 (32%) dogs that had episodes of SE died of causes directly attributed to the seizure disorder. Mean life spans of dogs that did and did not have episodes of SE were 8.3 and 11.3 years, respectively. Survival time was significantly different between groups. Results suggest that a substantial percentage of dogs with idiopathic epilepsy will have episodes of SE. Dogs with greater body weights were more likely to have episodes of SE, and early appropriate seizure treatment did not appear to decrease the risk that dogs would have episodes. Most dogs with idiopathic epilepsy had an expected life span, but survival time was shorter for dogs that had episodes of SE.
Article
To evaluate long-term mortality among people with status epilepticus (SE). The authors performed a population-based retrospective cohort study to determine long-term mortality after SE. Between January 1, 1965, and December 31, 1984, all first episodes of SE receiving medical attention were ascertained through the Rochester Epidemiology Project Records-Linkage System. Cases surviving the first 30 days (n = 145) were followed until death or study termination (February 1996). At 10 years, cumulative mortality among 30-day survivors was 43%. The standardized mortality ratio (SMR) at 10 years was 2.8 (95% CI, 2.1-3.5). The mortality rate of those with idiopathic/cryptogenic SE was not increased (SMR = 1.1; 95% CI, 0.5-2.3). The following characteristics of SE increased long-term risk for mortality: SE > or = 24 hours in duration vs. SE < 2 hours (relative risk [RR] = 2.3; 95% CI, 1.1-5.1); acute symptomatic etiology vs idiopathic/cryptogenic etiology (RR = 2.2; 95% CI, 1.0-5.1) SE; myoclonic SE vs generalized convulsive SE (RR = 4.0; 95% CI, 1.3-13). Forty percent of subjects who survived the first 30 days after an incident episode of SE die within the next 10 years. The long-term mortality rate was threefold that of the general population over the same time period. The long-term mortality rate at 10 years was worse for those with myoclonic SE, for those who presented with SE lasting more than 24 hours, and for those with acute symptomatic SE. The long-term mortality rate was not altered in those with idiopathic/cryptogenic SE. We conclude that SE alone does not modify long-term mortality.
Article
The purpose of this study was to investigate the prevalence and selected risk factors of epilepsy, the proportion of dogs with epilepsy in remission, and the types of seizures in Danish Labrador Retrievers. A prospective cross-sectional study of epilepsy was conducted in 1999-2000. The study was carried out in 2 phases in a reference population consisting of 29,602 individuals. In phase 1, 550 dogs were selected by random sampling stratified by year of birth. A telephone interview was used to identify dogs with possible epilepsy. In phase 2, dogs judged during phase 1 as possibly suffering from epilepsy were further subjected to physical and neurologic examination, CBC, blood chemistry, and a questionnaire on seizure phenomenology. Seventeen dogs were diagnosed with epilepsy, yielding a prevalence of 3.1% (95% CI 1.6-4.6%) in the Danish population of Labrador Retrievers. A diagnosis of epilepsy was 6 times more probable in dogs >4 years (born before 1995) than in younger dogs (born between 1995 and 1999) (P = .004, relative risk = 6.5). No significant difference in risk between genders was observed, nor could any effect of neutering be proven statistically. The frequencies of primary generalized seizures and partial seizures (with or without secondary generalization) were 24 and 70%, respectively. The type of seizures could not be classified in 6%. In conclusion, the 3.1% prevalence of epilepsy in Danish Labrador Retrievers is higher than the 1% prevalence of epilepsy described in the general canine population, establishing that this breed is at increased risk.
Article
Whether hippocampal neuron loss and/or hippocampal sclerosis is the 'cause' or 'consequence' of seizures has been a fundamental question in human epilepsy studies for over a century. To address this question, this study examined hippocampal specimens from temporal lobe epilepsy patients (TLE; n = 572) and those with extra-temporal seizures and pathologies (n = 73) for qualitative signs of hippocampal sclerosis and quantitative neuron loss using cell counting techniques. Patients were additionally classified based on pathological substrate, and history of an initial precipitating injury (IPI). Results showed that: (1) Hippocampal sclerosis was strongly linked with an IPI in both TLE and extra-temporal seizure patients. (2) In TLE cases, IPIs showed an early age preference and often involved seizures, but IPIs were not age dependent and older IPI cases showed sclerosis that was indistinguishable from younger IPI patients. (3) In TLE patients, longer seizure durations were associated with decreased neuronal densities in all hippocampal subfields. The decrease was independent of the neuron loss linked with IPIs, it occurred in all pathological groups, it occurred over 30 years or more, and was not a consequence of aging. (4) Intractable seizures in the young human hippocampus were not associated with neuronal damage, but were linked with decreased postnatal granule cell development and aberrant axon sprouting. These results support the concept that hippocampal sclerosis is likely an acquired pathology, and most of the neuronal loss occurs with the IPI. In addition, there is progressive hippocampal damage from intractable TLE regardless of pathology. Hence, hippocampal neuron loss can be the 'consequence' of repeated limbic seizures over 30 years or more, but is unlikely to 'cause' hippocampal sclerosis unless there is also an IPI.
Article
The clinical presentations of 119 canine seizures from 41 Standard Poodles and 11 Dalmatians were classified according to a modified version of the International League Against Epilepsy (ILAE) seizure classification system. Standardized use of the ILAE system with dogs not only should facilitate research in veterinary medicine, which has no standard criteria for seizure classification, but also should facilitate comparisons between canine and human seizures. We found that for more than 80% of both breeds, at least some of their seizures had partial onsets. However, because it was common for partial seizures to secondarily generalize, the majority of Poodles (81%) and Dalmatians (91%) experienced at least some generalized seizures. Among partial seizures, complex partial were more frequent than simple partial. For both breeds, two thirds of those with partial onset seizures had exclusively complex partial. Among dogs with primary or secondarily generalized seizures, 80% of both breeds had tonic-clonic seizures.
Article
Medical record, seizure survey, and telephone interview information was obtained for 29 Vizslas with idiopathic epilepsy (IE), 74 unaffected siblings, and 41 parents to determine the common clinical characteristics and most likely mode of inheritance. IE was diagnosed on the basis of the age of seizure onset, laboratory results, and neurologic examination findings. Computerized tomography (CT) or magnetic resonance imaging (MRI) scan with cerebrospinal fluid (CSF) analysis was required for the inclusion of dogs with an age of seizure onset of < 6 months or > 5 years. Simple segregation analysis was performed with an ascertainment correction and chi-square analysis. IE appeared to be familial in these pedigrees, with 79% of affected Vizslas exhibiting partial onset seizures. Partial seizure signs included a combination of limb tremors, staring, pupillary dilatation, or salivation without loss of consciousness in > 50% of the dogs with partial signs. The estimated segregation frequency of P = .22 (95% CI, P = .08 to .36) was consistent with autosomal recessive inheritance; however, polygenic inheritance could not be excluded as a possibility. Simulated linkage with FASTSLINK estimated that the average logarithm of odds (LOD) score would be 3.23 with a 10-centimorgan (cM) whole-genome scan for these families, indicating that these families would be useful for a whole-genome scan to potentially find the chromosomal segment(s) containing the epilepsy gene or genes. We conclude that IE in Vizslas appears to be primarily a partial onset seizure disorder that may be inherited as an autosomal recessive trait.
Article
The purpose of this study was to determine the frequency of different tumor types within a large cohort of cats with intracranial neoplasia and to attempt to correlate signalment, tumor size and location, and survival time for each tumor. Medical records of 160 cats with confirmed intracranial neoplasia evaluated between 1985 and 2001 were reviewed. Parameters evaluated included age, sex, breed, FeLV/FIV status, clinical signs, duration of signs, number of tumors, tumor location(s), imaging results, treatment, survival times, and histopathologic diagnosis. Most of the cats were older (11.3 +/- 3.8 years). Primary tumors accounted for 70.6% of cases. Metastasis and direct extension of secondary tumors accounted for only 5.6 and 3.8% of cases, respectively. Twelve cats (7.5%) had 2 or more discrete tumors of the same type, whereas 16 cats (10.0%) had 2 different types of intracranial tumors. The most common tumor types were meningioma (n = 93, 58.1%), lymphoma (n = 23, 14.4%), pituitary tumors (n = 14, 8.8%), and gliomas (n = 12, 7.5%). The most common neurological signs were altered consciousness (n = 42, 26.2%), circling (n = 36, 22.5%), and seizures (n = 36, 22.5%). Cats without specific neurological signs were common (n = 34, 21.2%). The tumor was considered an incidental finding in 30 (18.8%) cats. In addition to expected relationships (eg, meninges and meningioma, pituitary and pituitary tumors), we found that lesion location was predictive of tumor type with diffuse cerebral or brainstem involvement predictive of lymphoma and third ventricle involvement predictive of meningioma.
Article
A lack of thyroid hormone in the postnatal period causes an irreversible mental retardation, characterized by a slowing of thoughts and movements accompanied by prolonged latencies of several evoked potentials and slowed electroencephalographic rhythms. Here we show that in cultured hippocampal and cortical neurons from postnatal rats treatment with thyroid hormone not only up-regulates Na(+)-current densities but also increases rates of rise, amplitudes and firing frequencies of action potentials. Furthermore, we show that the regulation of the Na(+)-current density by thyroid hormones also occurs in vivo: recordings from acutely isolated cortical neurons obtained from hypothyroid, euthyroid and hyperthyroid postnatal rats showed that hypothyroidism decreases the ratio of Na(+) inward- to K(+) outward-currents while hyperthyroidism upregulates Na(+)-currents with respect to K(+)-currents. Our observation of a regulation of neuronal excitability by thyroid hormone offers a direct explanation for the origin of various neurological symptoms related to thyroid dysfunction.
Article
Host genetic factors are likely to contribute to differences in individual susceptibility to seizure-induced excitotoxic neuronal damage. Similarly, inbred strains of mice differ in their susceptibility to the kainic acid (KA) model of seizure-induced cell death, but the genes responsible for the differences are not known. Here, we define the inheritance patterns of susceptibility to KA-induced neurodegeneration in the hippocampus by assessing 331 back-cross (N2) progeny of two inbred mouse strains, C57BL/6 and FVB/N, previously shown to display resistance and sensitivity to KA-induced cell death, respectively. Results of phenotypic analysis suggest that the difference in susceptibility between these two strains is conferred by a single dominant gene. Therefore, we used an N2 back-cross between the inbred C57BL/6 and FVB/N strains for a genome-wide search for quantitative trait loci (QTLs), which are chromosomal sites containing genes influencing the magnitude of susceptibility. Genome-wide interval mapping in N2 progeny identified a locus on distal chromosome (Chr) 18 with a peak LOD score of 4.9 localized between D18Mit186 and D18Mit4 as having the strongest and most significant effect in this model. QTLs of minor effect were detected on Chr 15 (D15Mit174-D15Mit156) and Chr 4 (D4Mit264-D4Mit91), with peak LOD scores of 3.02 and 2.46, respectively. The three significant QTLs (Chrs 4, 15, 18) together account for nearly 25% of the trait variance for both genders combined. Reduced KA-induced cell death susceptibility was observed in a congenic strain in which the highly susceptible FVB/N strain carried putative resistance alleles from the C57BL/6 strain on Chr 18.
Article
Dogs with spontaneous occurring epilepsy with partial seizures express symptomatology resembling what is found in humans with partial epileptic seizures. Questionnaires on clinical signs from 70 dogs, with a confirmed diagnosis of epilepsy with partial seizures with or without secondary generalization, were reviewed in order to characterize and classify clinical signs of partial seizure activity in dogs and compare them to partial seizure phenomenology in humans. Signs of partial seizure activity were distributed into three categories: motor signs, autonomic signs and paroxysms of behavioral signs. Motor signs were described in 48 dogs (69%), autonomic signs in 16 dogs (23%) and paroxysms of behavioral signs in 56 dogs (80%). The majority of dogs expressed signs from more than one group. Sixty-one dogs (87%) had partial seizures with secondary generalization. Nine dogs (13%) had partial seizures without secondary generalization. The study shows a remarkable resemblance between the seizure phenomenology expressed in humans and canines with partial epileptic seizures.