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Isolated and Reversible Lesions of the Corpus Callosum: A Distinct Entity
Abstract
The Reversible Splenial Lesion Syndrome represents a distinct clinicoradiological syndrome, associated with several disorders, including infection, high altitude cerebral edema, antiepileptic drug withdrawal, and severe metabolic disturbances (hypoglycemia and hypernatremia). Clinical presentation is nonspecific, most frequently as an encephalopathy or encephalitis. Outcome is favorable in most patients unless there is a severe underlying disorder. Magnetic resonance imaging findings are restricted to the splenium and consist of a nonenhancing oval lesion, hyperintense on T2-weighted images, including FLAIR. Findings on diffusion-weighted imaging are consistent with cytotoxic edema except for high-altitude cerebral edema, where vasogenic edema is present. Resolution after weeks or months is the rule.
J Neuroimaging 2010;20:1-2.
... Reversible splenial lesion syndrome (RESLES) defined as clinico-radiological syndrome is identified by transient localized lesions in the splenium of the corpus callosum (SCC) on magnetic resonance imaging (MRI). It can be seen in a wide variety of clinical conditions including seizures [1,2], drug therapy [3] or withdrawal [4], viral encephalitis [5], hypoglycemic encephalopathy [6], eclampsia [7], Marchiafava-Bignami disease (MBD) [8], hypernatremia and hypoglycemia [9], high-altitude cerebral edema [9], meningitis [10], bacterial [11] and neoplasm [12]. However, the pathophysiological mechanism still remains to be understood. ...
... Reversible splenial lesion syndrome (RESLES) defined as clinico-radiological syndrome is identified by transient localized lesions in the splenium of the corpus callosum (SCC) on magnetic resonance imaging (MRI). It can be seen in a wide variety of clinical conditions including seizures [1,2], drug therapy [3] or withdrawal [4], viral encephalitis [5], hypoglycemic encephalopathy [6], eclampsia [7], Marchiafava-Bignami disease (MBD) [8], hypernatremia and hypoglycemia [9], high-altitude cerebral edema [9], meningitis [10], bacterial [11] and neoplasm [12]. However, the pathophysiological mechanism still remains to be understood. ...
Background
Reversible splenial lesion syndrome (RESLES) was reported to be associated with variable entities. However, much less is known about the cases in which the mental disorders act as the only manifestation.
Method
Total ten patients of RESLES were obtained in this retrospective study from Shenzhen Kangning Hospital. T1-fluid attenuated inversion recovery (T1-FLAIR), T2-weighted images, T2-FLAIR, diffusion-weighted images and apparent diffusion coefficient map were performed on all the patients. Clinical manifestations, laboratory examination results, magnetic resonance imaging (MRI) findings, treatments and outcomes were analyzed.
Result
All patients showed different mental disorders as the only manifestation. There were two cases of alcohol abuse, one of Asperger’s syndrome with malnutrition, one of infection and one of invasive pituitary adenoma. The other cases were diagnosis as major depressive disorder, dissociative and conversion disorders, undifferentiated somatoform disorder, unspecified psychosis and bipolar disorder, respectively. Three patients were completely recovered while the clinical symptoms of rest seven patients partially recovered at the follow-up three months later. Oval-shaped lesion centered on the splenial of corpus callosum (SCC) was observed in all patients using MRI. The lesions of SCC of all patients were completely resolved within five weeks.
Conclusions
We found that RESLES might only showed mental symptoms. On the one hand, for the patients with acute mental disorders, clinicians should be alert to the possibility of RESLES caused by physical disease. On the other hand, we suggest that mental disorder might be a precipitating factor of RESLES.
... Hypoglycemia is not the only condition that presents such reversible high signal intensity, as it has been described in patients with encephalitis, epileptic seizure, and metabolic disturbance. [9][10][11] However, when such a high signal intensity lesion is detected on MRI, it is important to check the blood sugar level promptly. If hypoglycemia is revealed, immediate recovery is crucial. ...
... There are two types of lesion in the splenium: Boomerang [8,13] and oval shaped. [10,15] There were two cases each in the present study. The significance of the shape of lesions remains unclear. ...
Introduction
It is well-known that localized reversible high signal intensities in the splenium of the corpus callosum or the basal ganglia appear on diffusion-weighted MRI in the presence of hypoglycemia. The aim of this study was to clarify the incidence and significance of such high signal intensity lesions.
Results
We analyzed 70 cases of hypoglycemia with consciousness disturbance referred to our outpatient office. Localized reversible high signal intensities on diffusion-weighted MRI were noted in 6 cases (8.6%). They were at the splenium of the corpus callosum in four cases (5.7%), and right frontal cortex and bilateral frontal white matter in one each. Convulsions were noted in five cases, and right hemiparesis was noted in three. None of the three cases of hemiparesis showed localized reversible high signal intensities on diffusion-weighted MRI. These lesions are reversible if the patients undergo treatment without delay.
Conclusion
The significance of these lesions is still unclear. However, when a high signal intensity lesion that is not reasonable for the symptom is detected on diffusion-weighted MRI, an immediate check of the blood sugar level is mandatory.
... In addition, an autoimmune hypothesis has been proposed, supported by associations with autoimmune diseases and the presence of antinuclear and anticentromere antibodies. 9 However, no definitive causal factor was identified in our patient, differing from literature hypotheses. ...
Parry-Romberg Syndrome (PRS), or progressive hemifacial atrophy, is a rare disorder marked by the progressive atrophy of skin and soft tissues, sometimes affecting muscles, cartilage, and bones. Typically manifesting in childhood, PRS has a 66% female predilection and sporadic occurrence. Diagnosis is clinical, supplemented by tests to exclude other conditions. Treatment options include bone/cartilage grafts, fat grafts, dermal fillers, and free tissue transplantation. Lipoinjection, using autologous adipose tissue enriched with stem cells, is a promising technique. A 33-year-old female with PRS exacerbated by pregnancy presented with severe right hemifacial atrophy. Initial lipoinjection elsewhere resulted in significant graft reabsorption. At our institution, a second lipoinjection was performed at age 34 after disease remission. Five months postoperatively, 30% graft reabsorption was noted, but significant improvement in facial symmetry was achieved. A second lipoinjection session further enhanced facial volume and skin quality. Four months postoperatively, the patient showed substantial improvement, with 90% facial symmetry and stable disease remission. Autologous lipoinjection is an effective treatment for PRS-related facial atrophy, offering minimal tissue rejection and satisfactory aesthetic outcomes. The presented case highlights the potential of this technique in achieving significant clinical improvement and facial symmetry in PRS patients.
... Regarding predisposing causes, all low-altitude subjects were infected before the scc lesion, which were mainly upper respiratory tract infections and pulmonary infections. in previous research, acute cerebral edema has been proven to be the main inducer of Resles at high altitudes [15]. however, we found that only two patients were diagnosed with hace. ...
Introduction
RESLES (Reversible splenial lesion syndrome) can be observed secondary to various diseases, and intramyelinic edema may play a crucial role in the pathogenesis of SCC (Splenium of the corpus callosum). Some studies have suggested that hypoxic-ischaemic encephalopathy may constitute a risk factor for SCC lesions. However, the potential impact of high-altitude environments on SCC, especially during chronic exposure, remain obscure.
Methods
Our study included 19 patients who satisfied the diagnostic criteria of RESLES at high altitudes. Ten low-altitude patients with RESLES were included as controls. All participants received MRI (Magnetic resonance imaging) scans twice. Routine blood tests, liver, kidney and thyroid function, coagulation function, electrolytes and vitamins were detected during hospitalization and before discharge. In addition, the patients were followed up in May 2023.
Results
Hypoxic environments at high altitudes may increase the risk of RESLES. The two groups showed different clinical symptoms. High-altitude patients had significantly higher CRP levels than low-altitude patients. The lesion size in high-altitude patients showed a positive correlation with SaO2 levels. However, the patients at low altitudes had positive correlation trends between lesion size and several inflammatory markers (WBC, NEU and CRP). All patients had a benign prognosis that may not be affected by the use of prednisone acetate.
Conclusions
Hypoxic environments at high altitudes may play a role in the aetiology of RESLES. Additionally, RESLES is a reversible disease and the administration of glucocorticoids may be dispensable for its treatment.
... Although some studies have suggested that anticonvulsive therapy plays a role, 3,4 the largest study so far found no significant differences in the antiseizure drug treatment between 24 patients with splenial edema and ageand epilepsy-matched patients without. 5 FESCC has been described in a variety of other diseases, most often in cases of acute encephalopathy 6,7 due to primarily neurologic causes, as well as secondary to metabolic and infectious diseases. 8,9 Identification of the cause of FESCC is frequently hampered by coexisting potential etiologies. ...
Objective
Focal edema of the splenium of the corpus callosum (FESCC) is infrequently seen in patients with epilepsy who are undergoing video–electroencephalography (EEG) monitoring. It is diagnosed by qualitative visual inspection of the magnetic resonance imaging (MRI) and is usually assumed to be a dichotomous phenomenon. Rapid reduction of anticonvulsants has been proposed as a cause. In this study we investigate the relationship between dose reduction of anticonvulsants and the occurrence of FESCC, based on absolute drug doses.
Methods
We examined in detail the anticonvulsive therapy of all patients during video‐EEG monitoring between 2014 and 2018. We compared patients with a radiologically diagnosed FESCC to controls in a 1:2 case‐control analysis matched by age, epilepsy syndrome, and adjacent time of admission. In a separate correlation analysis, we examined quantitative effects of reduction of antiseizure drugs on diffusion restriction in the corpus callosum.
Results
Of 326 patients who had an MRI following video‐EEG monitoring, 12 (3.7%) had FESCC. Antiseizure drugs were reduced to a significantly greater extent in FESCC patients than in the 24 controls (P < 0.001). Sodium channel–blocking antiseizure drugs were reduced (P < 0.001) and reintroduced (P < 0.001) significantly faster in FESCC patients, and the duration of anticonvulsant discontinuation was longer in FESCC patients (P < 0.001). The separate correlation analysis in 325 patients shows a weak correlation between diffusion restriction in the splenium and the reduction rate of sodium channel–blocking anticonvulsants (r = −0.15, P = 0.03) as well as the duration of their discontinuation (r = −0.16, P = 0.01). No such effects were found for anticonvulsants with other modes of action.
Significance
Our findings substantiate that FESCC is associated with high rates of dose reduction of anticonvulsants, specifically those acting on sodium channels. Our results cautiously suggest that reducing sodium‐channel blockers has a small effect on diffusivity in the splenium below the visual threshold.
... Most studies suggested cellular fluid regulation abnormalities and myelin edema induced by changes in salt homeostasis in RESLES. [2] The manifestation is nonspecific, including altered states of consciousness, delirium, headache, and seizures. [3] Specifically, callosal disconnection syndromes in RESLES has received little attention. ...
Rationale:
Reversible splenial lesion syndrome (RESLES) is a reversible condition with an excellent prognosis in most patients. The clinical features include altered states of consciousness, delirium, headache, and seizures, but no callosal disconnection syndromes have been described in RESLES.
Patient concerns:
We presented a 57-year-old patient with alien hand syndrome, autotopagnosia, gait disorders, and left ideomotor apraxia after blood transfusion. The brain magnetic resonance imaging (MRI) showed a few regions with high signal intensity in the genu, body, and splenium of the right corpus callosum on diffusion weighted images. Cerebrovascular examination was unremarkable.
Diagnoses:
He was diagnosed with RESLES and callosal disconnection syndrome.
Interventions:
The patient received symptomatic and supportive treatment in our hospital.
Outcomes:
He recovered to baseline on following up of 6 months and abnormalities on brain MRI completely disappeared.
Lessons:
Neurologists should be aware of the symptoms of callosal disconnection syndrome in RESLES. In addition, caution should be taken when transfusing blood products in patients with gastrointestinal bleeding.
... 8 Compared with the literature, the present case reports suggest that MERS could be more severe in adults than in children. Among the rare adult case reports, we found two cases of EBV encephalitis, 9,10 one of tick-borne encephalitis (CSF WBC 33/µL), 13 one of anti-Yo rhombencephalitis, 14 one of viral encephalitis of unknown etiology (CSF WBC 408/µL), 15 one of influenza virus A encephalitis, one of HIV encephalitis, and some cases of MERS associated with systemic infections. 11,16,17 Among these cases, CSF WBC count and protein level were both unremarkable. ...
Background
Approximately 200 cases of mild encephalitis with reversible splenial (MERS) and deep cerebral white matter lesions have been reported since MERS was first defined in 2004. MERS occurs more frequently in children; in adults, only ~60 cases have been reported. Until now, only four cases of MERS in adults have been associated with Epstein–Barr virus (EBV).
Case presentation
We report three adult cases of MERS associated with EBV infection in China. For all three patients, cranial magnetic resonance imaging (MRI) indicated solitary reversible splenial and/or perilateral ventricle white matter lesions with reduced diffusion. In the present report, all patients were adults presenting with high fever, headache, apathy, and confusion, as well as significant signs of meningeal inflammation. These symptoms peaked 10–14 days after disease onset, with serious hyponatremia (112–129 mmol/L), an elevated cerebrospinal fluid white blood cell count (80–380/mm³), and significantly increased protein levels (1,010–1,650 mg/dL). Cranial MRI indicated abnormal signal intensity in the splenium of corpus callosum and symmetrically reversible lesions scattered in the thalamus and deep cerebral white matter. The clinical symptoms tended to improve after ~10–14 days of antiviral treatment. However, these patients recovered more slowly than patients with viral meningitis.
Conclusion
MERS associated with EBV infection in adults occurs less frequently but with more severe symptoms than in children. EBV infection should be considered for patients with MERS symptoms. MERS has a good prognosis.
... RESLES patients were given glucocorticoid, antiepileptic drugs, antiviral drugs, intravenous g-globulin, and/or other therapies not specifically targeted to encephalitis/encephalopathy in a previous report. [10] All patients were reported to have complete resolution of neurological symptoms. There is another report on RESLES patient who has improved under monoclonal antibody therapy. ...
Background
Reversible splenial lesion syndrome (RESLES) is a newly recognized syndrome, and a reversible progress associated with transiently reduced diffusion lesion in the splenium of the corpus callosum (SCC) is the typical pathological finding. The routine clinical symptoms include mildly altered states of consciousness, delirium, and seizures.
Methods
We presented a 14-year-old patient with signs suggestive of transient ischemic attack (TIA), including triple episodic weakness on the right upper limb, slurred speech, and bucking, lasting several hours in each time 2 days ago. She just had a slight cold 2 weeks ago.
Results
No evidence of abnormality was found in laboratory examinations except an elevated percentage of lymphocyte. Magnetic resonance imaging revealed lesions in splenium of the corpus callosum and frontal-parietal subcortex on both cerebral hemispheres. Cerebrovascular examination was also unremarkable. The patient recovered to baseline within 25 hours. No treatment was given to her in hospital. In addition, the follow-up brain magnetic resonance imaging scan showed reduced lesions. TIA-like symptoms did not occur during a 30-day follow-up period.
Conclusion
This young patient with RESLES type II exhibited TIA-like symptoms, which was not previously reported in literature. This case extends the recognized clinical phenotypes for this disorder.
... It is also observed in patients with epilepsy receiving antiepileptic drugs (especially phenytoin and carbamazepine), metabolic disorders (hypoglycemia or hypernatremia), and autoimmune disease (4,5) . The term "reversible splenial lesion syndrome (RESLES)" refers to a distinct clinicoradiological syndrome generally with a benign course and good prognosis (6) . ...
Reversible splenial lesion syndrome is a distinct clinicoradiological syndrome with diverse etiologies. Hypoglycemia induced reversible splenial lesion syndrome has been documented in adults and children, but rare in neonates. We demonstrate a neonate with hypoglycemia presenting with a typical reversible splenial syndrome.
Patient A four-day-old male neonate had hypoglycemia and seizure, whose symptoms improved soon after glucose supplementation. Magnetic resonance imaging examination showed restricted diffusion of the splenium of the corpus callosum. Proton MR spectroscopy revealed a decreased N-acetylaspartate peak. The lesion resolved in subsequent MRI images. The patient is free from clinical symptoms and has normal development currently.
The patient presented typical clinical course and radiological features of reversible splenial lesion syndrome. Through timely and proper treatment, the outcome could be favorable.
... Brain shrinkage induced by hypernatremia can cause rupture of cerebral veins, with focal intracerebral and subarachnoid hemorrhages (Adrogue and Madias, 2000a). Hypernatremia is among the causes of the so-called reversible splenial lesion syndrome, a localized cytotoxic edema restricted to the splenium and identified as a nonenhancing T2-weighted and FLAIR hyperintense oval lesion by magnetic resonance imaging (Garcia-Monco et al., 2010). This syndrome has also been reported in association with high-altitude cerebral edema, infectious encephalitis, antiepileptic drug withdrawal, and hypoglycemia ( The typical presentation of diabetes insipidus (see below) is a relatively rapid onset of polyuria, polydipsia, and nocturia (Bichet, 2006). ...
Electrolyte and acid-base disturbances are common occurrences in daily clinical practice. Although these abnormalities can be readily ascertained from routine laboratory findings, only specific clinical correlates may attest as to their significance. Among a wide phenotypic spectrum, acute electrolyte and acid-base disturbances may affect the peripheral nervous system as arreflexic weakness (hypermagnesemia, hyperkalemia, and hypophosphatemia), the central nervous system as epileptic encephalopathies (hypomagnesemia, dysnatremias, and hypocalcemia), or both as a mixture of encephalopathy and weakness or paresthesias (hypocalcemia, alkalosis). Disabling complications may develop not only when these derangements are overlooked and left untreated (e.g., visual loss from intracranial hypertension in respiratory or metabolic acidosis; quadriplegia with respiratory insufficiency in hypermagnesemia) but also when they are inappropriately managed (e.g., central pontine myelinolisis when rapidly correcting hyponatremia; cardiac arrhythmias when aggressively correcting hypo- or hyperkalemia). Therefore prompt identification of the specific neurometabolic syndromes is critical to correct the causative electrolyte or acid-base disturbances and prevent permanent central or peripheral nervous system injury. This chapter reviews the pathophysiology, clinical investigations, clinical phenotypes, and current management strategies in disorders resulting from alterations in the plasma concentration of sodium, potassium, calcium, magnesium, and phosphorus as well as from acidemia and alkalemia.
... Though radiologic or pathologic confirmation of Legionellosis is reported to be rare, one previously recorded case study on Legionellosis with cerebellar involvement also describes an isolated enhancing lesion of the SCC on MRI [4]. This nonspecific reversible lesion [31] has been described previously in a host of infectious32333435 and non-infectious [34] causes, including antiepileptic drug-withdrawal, high-altitude cerebral edema, and metabolic disorders [35] . The frequency of this lesion is likely underreported, since most patients who present with altered mental status do not receive an MRI. ...
Background
Legionella pneumophila is a common cause of community-acquired pneumonia. Central nervous system dysfunction is common, and diagnosis in the absence of pulmonary symptoms can be challenging. Here we describe an atypical clinical presentation of Legionella infection in a patient with HIV who was found to have an unusual neuroradiologic lesion that further served to obscure the diagnosis. This is the first such description in a patient with Legionellosis and HIV coinfection.
Case presentation
A 43 year-old HIV positive man presented to our hospital with dysarthria, fevers, headache, and altered mental status. Initial work-up revealed pneumonia and a lesion of the splenium of the corpus callosum on magnetic resonance imaging. He was subsequently diagnosed with Legionella pneumonia and treated with complete symptom resolution.
Conclusions
Neurologic abnormalities are frequent in Legionellosis, but the diagnosis may be difficult in the absence of overt respiratory symptoms and in the presence of HIV coinfection. A high index of suspicion and early initiation of empiric antibiotics is imperative since early treatment may help prevent long-term sequelae. Neuroimaging abnormalities, though rare, can help the physician narrow down the diagnosis and avoid unnecessary invasive testing. Future studies should aim to elucidate the as yet unknown role of neuroimaging in the diagnoses and prognostication of Legionellosis, as well as the interaction between Legionella infection and HIV.
... In addition to their presence in MERS, reversible focal lesions in the SCC have been reported in patients with seizures, antiepileptic drug toxicity/withdrawal, hypoglycemia , Wernicke encephalopathy, Marchiafava-Bignami disease, sympathomimetic-induced kaleidoscopic visual illusion syndrome, hemolytic uremic syndrome, altitude brain injury and acute axonal injury [4,6]. However, these conditions were ruled out for our patient based on the clinical profile, as there was no history of seizure, hypoglycemia, alcohol and drug use, renal dysfunction, malnutrition or trauma. ...
Patients with clinically mild encephalitis/encephalopathy with a reversible splenial lesion present with relatively mild central nervous system disturbances. Although the exact etiology of the condition remains poorly understood, it is thought to be associated with infective agents. We present a case of a patient with mild encephalitis/encephalopathy with a reversible splenial lesion, who had the unusual feature of acute urinary retention.
A 23-year-old Japanese woman developed mild confusion, gait ataxia, and urinary retention seven days after onset of fever and headache. Magnetic resonance imaging demonstrated T2 prolongation in the splenium of the corpus callosum and bilateral cerebral white matter. These magnetic resonance imaging abnormalities disappeared two weeks later, and all of the symptoms resolved completely within four weeks. Except for the presence of acute urinary retention (due to underactive detrusor without hyper-reflexia), the clinical and radiologic features of our patient were consistent with those of previously reported patients with mild encephalitis/encephalopathy with a reversible splenial lesion. To the best of our knowledge, this is the first report of acute urinary retention recognized in a patient with mild encephalitis/encephalopathy with a reversible splenial lesion.
Our findings suggest that mild encephalitis/encephalopathy with a reversible splenial lesion can be associated with impaired bladder function and indicate that acute urinary retention in this benign disorder should be treated immediately to avoid bladder injury.
... This finding is reversible. The MRI finding is not specific and has been reported with other infections, high-altitude brain edema, and certain metabolic states such as hypernatremia [29]. CSF analysis is unremarkable. ...
Influenza virus infection of the respiratory tract is associated with a range of neurologic complications. The emergence of 2009 pandemic influenza A (H1N1) virus has been linked to neurological complications, including encephalopathy and encephalitis.
Case report and literature review.
We reviewed case management of a 20-year old Hispanic male who developed febrile upper respiratory tract signs and symptoms followed by a confusional state. He had rapid neurologic decline and his clinical course was complicated by refractory seizures and malignant brain edema. He was managed with oseltamavir and peramavir, corticosteroids, intravenous gamma globulin treatment, anticonvulsants, intracranial pressure management with external ventricular drain placement, hyperosmolar therapy, sedation, and mechanical ventilation. Reverse transcriptase polymerase chain reaction analysis of nasal secretions confirmed 2009 H1N1 virus infection; cerebrospinal fluid (CSF) was negative for 2009 H1N1 viral RNA. Follow-up imaging demonstrated improvement in brain edema but restricted diffusion in the basal ganglia. We provide a review of the clinical spectrum of neurologic complications of seasonal influenza and 2009 H1N1, and current approaches towards managing these complications.
2009 H1N1-associated acute encephalitis and encephalopathy appear to be variable in severity, including a subset of patients with a malignant clinical course complicated by high morbidity and mortality. Since the H1N1 influenza virus has not been detected in the CSF or brain tissue in patients with this diagnosis, the emerging view is that the host immune response plays a key role in pathogenesis.
Background:
Transient splenial oedema, also known as reversible splenial lesion syndrome (RESLES), is a rare magnetic resonance imaging (MRI) finding that presents as a round or ovoid focal oedema in the posterior corpus callosum, associated with a wide range of clinical conditions. The aetiology of RESLES is not fully clear. Here, we investigated conflicting pathophysiological hypotheses by measuring local glucose metabolism in patients with RESLES.
Methods:
We retrospectively analysed patients with RESLES after reductions in antiseizure medications during in-hospital video electroencephalography (VEEG)-monitoring. We measured local glucose uptake using positron emission tomography/computed tomography (PET/CT) and compared matched cohorts of patients with and without MRI evidence of RESLES using non-parametric tests.
Results:
Local glucose metabolism in the splenium of 7 patients with RESLES was not significantly different from the glucose metabolism of the 7 patients in the matched cohort. This was true using both regular and normalised standardised glucose uptake value calculation methods (p = 0.902 and p = 0.535, respectively).
Conclusion:
We found no evidence of local glucose hypometabolism in RESLES, which supports previous pathophysiological considerations that suggest that RESLES is an intercellular, intramyelinic oedema rather than a typical intracellular cytotoxic oedema, which is not reversible.
The term encephalopathy describes a general alteration in brain function manifesting as an attentional disorder anywhere within the continuum between a hyperalert agitated state and coma and typically refers to the commonly encountered clinical scenario of diffuse brain dysfunction due to a systemic illness or metabolic or toxic derangement. This chapter discusses an approach to the emergency evaluation and management of patients with encephalopathy, with an emphasis on those causes of toxic-metabolic encephalopathy that will lead to irreversible neurological dysfunction if not recognized and treated urgently, as well as those encephalopathies whose recognition might lead to more prompt diagnosis and treatment of the causative medical illness. The encephalopathies discussed in this chapter are divided into four common, though overlapping, scenarios the neurologist is likely to encounter in clinical practice: encephalopathy from metabolic disorder or deficiency, encephalopathy due to a severe systemic illness or organ failure, encephalopathy due to medication-related toxicity, and encephalopathies diagnosable primarily by findings on brain imaging. In many cases, a specific etiological diagnosis can be made by history, examination, laboratory studies, and, in some cases, imaging, resulting in specific medical intervention and rapid clinical resolution, which helps prevent irreversible neurologic dysfunction. Patients with diffuse, toxic-metabolic encephalopathies are medically and secondarily neurologically ill. The evaluation and management of patients with diffuse encephalopathies represents a unique and important opportunity for the neurologist to positively impact the medical management, and both the neurological and medical recovery, of these systemically ill patients.
Background:
The term cytotoxic lesions of the corpus callosum (CLOCCs) encompasses the entity reversible splenial lesion syndrome (RESLES). RESLES typically presents with altered levels of consciousness, seizures, and delirium and is distinguished radiographically by reversible focal lesions of the splenium of the corpus callosum. This disease pathology is associated with withdrawal of antiepileptic medications, infections, metabolic disturbance, or high-altitude cerebral edema.
Methods:
We presented an otherwise healthy 72-year-old female that was consulted for an episode of isolated vertigo lasting four hours. Initial workup included CT head without contrast, CT angiogram head and neck, and MRI brain with and without contrast. The patient experienced recurrent episodes of vertigo at one and four months after initial presentation. An extensive workup at one month included a wide spectrum of laboratory tests and repeat imaging.
Results:
Noncontrast CT of the head and CT angiogram of the head and neck were reassuring. MRI brain with and without contrast demonstrated hyperintensity in the splenium of the corpus callosum on FLAIR sequencing. A follow-up visit at one month revealed vitamin B12 deficiency and unchanged hyperintensity of the splenium of the corpus callosum. History and workup were negative for typical risk factors associated with RESLES.
Conclusion:
An otherwise healthy patient who presented with an isolated episode of vertigo was discovered to demonstrate radiographic features consistent with RESLES but lacked the common risk factors and typical presentation of RESLES. This case expands the possible clinical presentation of RESLES and highlights the possible relationship between vitamin B12 deficiency and radiographic features of RESLES.
Background
Reversible splenial lesion syndrome (RESLES) was reported to be associated with variable entities. However, much less is known about the cases in which the mental disorders act as the only manifestation.
Method
Total ten patients of RESLES were obtained in this retrospective study from Shenzhen Kangning Hospital. T1-fluid attenuated inversion recovery (T1-FLAIR), T2-weighted images, T2-FLAIR, diffusion-weighted images and apparent diffusion coefficient map were performed on all the patients. Clinical manifestations, laboratory examination results, magnetic resonance imaging (MRI) findings, treatments and outcomes were analyzed.
Result
All patients showed different mental disorders as the only manifestation. There were two cases of alcohol abuse, one of Asperger’s syndrome with malnutrition, one of infection and one of invasive pituitary adenoma. The other cases were diagnosis as major depressive disorder, dissociative and conversion disorders, undifferentiated somatoform disorder, unspecified psychosis and bipolar disorder, respectively. Three patients were completely recovered while the clinical symptoms of rest seven patients partially recovered at the follow-up three months later. Oval-shaped lesion centered on the splenial of corpus callosum (SCC) was observed in all patients using MRI. The lesions of SCC of all patients were completely resolved within five weeks.
Conclusion
MRI is an essential tool to identify the RESLES. For the patients with acute mental disorders, clinicians should be alert to the possibility of RESLES. Excluding other possible etiologies, we suggest that different mental disorders might be precipitating factors of RESLES.
A 42-year-old woman with reversible splenial lesion syndrome (RESLES) and rectal adenocarcinoma presented with sudden-onset delirium after the sixth cycle of her chemotherapy drug, oral tegafur-uracil (300 mg/m2/day, days 1–14, with treatment cycle repeated every 21 days). Accompanied by the anti-CV2 antibody, paraphasia, and a loss of bimanual coordination, the patient’s etiology and clinical manifestations of RESLES are unlike those of other reported cases of RESLES. Tegafur-uracil is an oral fluoropyrimidine that has a similar effect to 5-fluorouracil as an adjuvant treatment for colorectal cancer. The possibility that the toxicity of chemotherapeutic drugs may play a role in the pathogenesis of cytotoxic edema in the splenium of the corpus callosum and extracallosal white matter should be investigated further.
Objective: To investigate the clinical and imaging features of mild encephalitis/encephalopathy with a reversible splenial lesion of corpus callosum (MERS) in children. Methods: Four patients of MERS, who were diagnosed and treated in the First Hospital of Jilin University during 2013-2014, were collected retrospectively. Their clinical, laboratory, radiologic data and the related literatures were reviewed. Results: Four patients onsetted as gastrointestinal symptom (3 cases) or respiratory (1 case) symptom, in accompany with disturbance of consciousness (3 cases of drowsiness, 1 case of lethargy), convulsions (4 cases), headache (1 case) as the main symptoms. Abnormal neurological signs included positive cervical resistance (3 cases), positive bilateral Babinski sign (3 cases), bilateral chemosis (2 cases). Laboratory test showed the average blood sodium was 131.6 mmol/L, while the cerebrospinal fluid test only showed abnormality in 1 case. In etiology examination, 2 cases showed human rotavirus antigen positive, and Mycoplasma neumonia antibody was found positive in 2 cases. Cranial MRI showed reversible lesion in the splenium of corpus callosum (patchy iso- or hypo-intensity on T1WI and apparent diffusion coefficient, hyper-intensity on T2WI, FLAIR and DWI, clear boundary). After active treatment, clinical symptoms disappeared within 1 week, and cranial MRI lesions disappeared within 2 weeks. Conclusion: The clinical presentations of MERS, which is a clinical-radiological syndrome, are sudden onset and mild, with characteristic changes in brain MRI and good prognosis.
Background: Mild encephalitis/encephalopathy with a reversible splenial lesion (MERS) is a clinical-radiological entity, characterized by mild encephalitis or encephalopathy associated with a reversible lesion of the corpus callosum, which commonly involves the splenium. MERS with autoimmune thyroid disease has rarely been reported.
Case Report: A 37-year-old man with Grave’s disease presented to our institution, with symptoms of confused mentality, visual hallucinations, headache, and fever. Because there was no other etiology for changed mentality, headache, and fever, except for elevated antithyroid antibodies (antimicrosomal antibodies, anti-thyroglobulin antibody, and thyrotropin binding inhibitor immunoglobulin) in the blood and mild pleocytosis in the CSF study, we diagnosed the case as steroid responsive encephalopathy associated with autoimmune thyroiditis (SREAT). A hyperintense signal on T2-weighted images, a hypointense signal on T1-weighted images, and a non-enhancing lesion in the splenium of corpus callosum on initial magnetic resonance imaging (MRI) disappeared on follow-up MRI, which was compatible with the criteria of MERS.
Conclusions: Although MRI images in autoimmune thyroid disease have usually been unremarkable, we report a case of MERS in SREAT.
The term encephalopathy describes a general alteration in brain function manifesting as an attentional disorder anywhere within the continuum between a hyperalert agitated state and coma, and typically refers to the commonly encountered clinical scenario of diffuse brain dysfunction felt to be due to a systemic, metabolic, or toxic derangement. This chapter discusses an approach to the emergency evaluation and management of patients with encephalopathy, with an emphasis on those causes of toxic-metabolic encephalopathy that will lead to irreversible neurological dysfunction if not recognized and treated urgently, as well as those encephalopathies whose recognition might lead to more prompt diagnosis and treatment of the causative medical illness. The encephalopathies discussed in this chapter are divided into four common, though overlapping, scenarios the neurologist is likely to encounter in clinical practice: encephalopathy from metabolic disorder or deficiency, encephalopathy due to a severe systemic illness or organ failure, encephalopathy due to medication-related toxicity, and encephalopathies diagnosable primarily by findings on brain imaging. In many cases a specific etiological diagnosis can be made—via history, examination, laboratory studies, and in some cases, imaging—which may lead to specific medical intervention and more rapid clinical resolution, and may help prevent irreversible neurologic dysfunction. Since patients with diffuse, toxic-metabolic encephalopathies are medically—and secondarily neurologically—ill, the evaluation and management of patients with diffuse encephalopathies represents a unique and important opportunity for the neurologist to positively impact the medical management, and both the neurological and medical recovery, of these systemically ill patients.
Encephalopathy is one of the most commonly encountered neurologic manifestations of systemic illness, as the brain is highly susceptible to being adversely affected by illness elsewhere in the body and by many of the medications used in the treatment of these illnesses. This chapter reviews a number of both common and rare systemic diseases that can result in encephalopathy, highlighting those potentially reversible systemic etiologies that result in well-defined and unique clinical signs and symptoms. Encephalopathic systemically ill patients will often have a multitude of potential etiologies of their encephalopathy and often the most obvious cause is not the sole answer. Clinical improvement and ultimately a good prognosis are possible for many of the encephalopathies, but depend on prompt recognition and the prompt initiation of the appropriate interventions. With a high index of suspicion and meticulous neurologic assessment, devastating neurologic outcomes may be prevented.
Isolated and reversible lesion restricted to the splenium of the corpus callosum, known as reversible splenial lesion syndrome, have been reported in patients with infection, high-altitude cerebral edema, seizures, antiepileptic drug withdrawal, or metabolic disturbances. Here, we report a 39-year-old female patient with glufosinate ammonium (GLA) poisoning who presented with confusion and amnesia. Diffusion-weighted magnetic resonance imaging of the brain revealed cytotoxic edema of the splenium of the corpus callosum. The lesion was not present on follow-up MR imaging performed 9 months later. We postulate that a GLA-induced excitotoxic mechanism was the cause of this reversible splenial lesion.
Copyright © 2015 by the American Society of Neuroimaging.
The etiopathogenesis of essential tremor (ET) is still debated, since the predominant role of circuit dysfunction or brain degenerative changes has not been clearly established. The relationship with Parkinson’s Disease (PD) is also controversial and resting tremor occurs in up to 20 % of ET. We investigated the morphological and functional changes associated with ET and we assessed potential differences related to the presence (ET+R) or absence (ET−R) of resting tremor. 32 ET patients (18 ET+R; 14 ET−R) and 12 healthy controls (HC) underwent 3T-MRI protocol including Spoiled Gradient T1-weighted sequence for Voxel-Based Morphometry (VBM) analysis and functional MRI during continuous writing of “8” with right dominant hand. VBM analysis revealed no gray and white matter atrophy comparing ET patients to HC and ET+R to ET−R patients. HC showed a higher BOLD response with respect to ET patients in cerebellum and other brain areas pertaining to cerebello-thalamo-cortical circuit. Between-group activation maps showed higher activation in precentral gyrus bilaterally, right superior and inferior frontal gyri, left postcentral gyrus, superior and inferior parietal gyri, mid temporal and supramarginal gyri, cerebellum and internal globus pallidus in ET−R compared to ET+R patients. Our findings support that the dysfunction of cerebello-thalamo-cortical network is associated with ET in absence of any morphometric changes. The dysfunction of GPi in ET+R patients, consistently with data reported in PD resting tremor, might suggest a potential role of this structure in this type of tremor.
Stroke is the third leading cause of death in the USA. An estimated 795,000 new or recurrent stroke events occur annually, mostly ischemic in nature. Arterial recanalization and subsequent reperfusion performed shortly after symptom onset can help to restore brain function in acute ischemic stroke (AIS). The only treatment currently approved by the United States Food and Drug Administration is intravenous tissue plasminogen activator, administered within 4.5 h of symptom onset. However, this short window often precludes effective intervention. Mechanical neurothrombectomy devices offer many potential advantages over pharmacologic thrombolysis, including more rapid achievement of recanalization, enhanced efficacy in treating large-vessel occlusions, and a potentially lower risk of hemorrhagic events. The goal of this chapter is to describe the state-of-the-art neurothrombectomy devices and stenting techniques for endovascular treatment of acute ischemic stroke, as well as to highlight recent advances in reperfusion therapies. Ongoing clinical trials, some with randomized, controlled designs, are included.
The definition of the clinicoradiologic syndrome posterior reversible leukoencephalopathy syndrome (PRES) has been stretched over the last decade.(1) Many regard PRES as a final common denominator for various cerebral insults, without a single etiopathogenic trigger.(1,2) The hallmark of classic PRES is hydrostatic pressure breakthrough causing cerebral vasogenic edema, commonly coupled with a history of refractory hypertension, ictal surge in blood pressure (BP), and a concomitant systemic inflammatory or uremic process.(1) High BP may be absent in PRES if there is renal failure; infection or any systemic inflammatory response syndrome; or immunomodulation as seen in eclampsia, autoimmune disorders, or chemotherapy.(1-3) PRES may thus be better defined as a neurotoxic syndrome(2) with blood-brain barrier opening or with disruption of cerebral autoregulation leading to dysperfusion with either vasogenic or cytotoxic edema.(2,3) The phenotypic umbrella of PRES now includes transient, isolated splenial edematous lesions(4) and extensive spinal cord edema. A mounting number of cases of longitudinally extensive central cord edema in the absence of infectious, demyelinating, or ischemic causes or venous engorgement from an arteriovenous fistula now warrant codifying this entity as a discrete clinical syndrome and perusal for specific risk factors.
La RM de cuerpo entero en difusión (RM-CC-D) es una técnica con un potencial emergente en la valoración integral de todo el cuerpo en un único estudio para evaluar patología sistémica. La progresiva evolución de la técnica hace posible su implantación en la mayoría de equipos actuales de RM. La RM-CC-D permite el análisis global del paciente oncológico o con enfermedad benigna multisistémica. La ventaja de la técnica de RM-CC-D es de proporcionar información tanto cuantitativa como cualitativa de todo el cuerpo. Se describen. La secuencia RM difusión (DWI) debe utilizarse en combinación con las otras secuencias estándar como espín eco ponderada en T1 y STIR. Un protocolo completo de todo el cuerpo incluyendo la RM DWI puede realizarse en menos de 40 min. Se describen los aspectos técnicos de la RM-CC-D con especial énfasis en el procesamiento y análisis de imágenes; y las aplicaciones clínicas, limitaciones y los estudios comparativos con otras técnicas de cuerpo entero en relación a la técnica de RM-CC-D.
Transient lesions involving the splenium of the corpus callosum — reversible splenial lesion syndrome (RESLES) or mild encephalitis/encephalopathy with a reversible isolated splenium of the corpus callosum lesion (MERS) — have been described in patients with encephalopathy of various etiologies but rarely in systemic lupus erythematosus (SLE), limited to a case series of 3 patients1,2,3 …
Acute treatment of ischemic stroke patients presenting more than eight-hours after symptom onset remains limited and largely unproven. Partial aortic occlusion using the NeuroFlo catheter can augment cerebral perfusion in animals. We investigated the safety and feasibility of employing this novel catheter to treat ischemic stroke patients eight-hours to 24 h following symptom onset.
A multicenter, single-arm trial enrolled ischemic stroke patients at nine international academic medical centers. Eligibility included age 18–85 years old, National Institutes of Health stroke scale (NIHSS) score between four and 20, within eight-hours to 24 h after symptom onset, and perfusion–diffusion mismatch confirmed by magnetic resonance imaging. The primary outcome was all adverse events occurring from baseline to 30 days posttreatment. Secondary outcomes included stroke severity on neurological indices through 90 days. This study is registered with ClinicalTrials.gov, number NCT00436592.
A total of 26 patients were enrolled. Of these, 25 received treatment (one excluded due to aortic morphology); five (20%) died. Favorable neurological outcome at 90 days (modified Rankin score 0–2 vs. 3–6) was associated with lower baseline NIHSS (P < 0·001) and with longer duration from symptom discovery to treatment. There were no symptomatic intracranial hemorrhages or parenchymal hematomas. Asymptomatic intracranial hemorrhage was visible on computed tomography in 32% and only on microbleed in another 20%.
Partial aortic occlusion using the NeuroFlo catheter, a novel collateral therapeutic strategy, appears safe and feasible in stroke patients eight-hours to 24 h after symptom onset.
We report a patient with neonatal Coxsackie B2 meningo-encephalitis in whom magnetic resonance imaging (MRI) could be performed serially from the early stage of the disease. The patient was a 12-day-old girl born at a gestational age of 37 weeks. She was hospitalized due to poor suckling. During her hospital stay, she developed clonic seizures in the right upper and lower limbs. Coxsackie B2 virus was detected, and a diagnosis of viral encephalitis was made. The first diffusion-weighted images (DWI) showed an abnormal high-intensity area restricted to the corpus callosum and posterior limb of the internal capsule 8 h after onset of seizures. Repeated MRI revealed damage to the white matter, which finally changed into diffuse excessive necrosis followed by cystic leukomalacia. Early DWI is valuable for the early detection and diagnosis of neonatal meningo-encephalitis. This is the first report of the detailed neuroradiological course of neonatal Coxsackie B2 meningo-encephalitis.
To estimate longitudinal changes in a quantitative whole-brain and tract-specific MRI study of multiple sclerosis (MS), with the intent of assessing the feasibility of this approach in clinical trials.
A total of 78 individuals with MS underwent a median of 3 scans over 2 years. Diffusion tensor imaging indices, magnetization transfer ratio, and T2 relaxation time were analyzed in supratentorial brain, corpus callosum, optic radiations, and corticospinal tracts by atlas-based tractography. Linear mixed-effect models estimated annualized rates of change for each index, and sample size estimates for potential clinical trials were determined.
There were significant changes over time in fractional anisotropy and perpendicular diffusivity in the supratentorial brain and corpus callosum, mean diffusivity in the supratentorial brain, and magnetization transfer ratio in all areas studied. Changes were most rapid in the corpus callosum, where fractional anisotropy decreased 1.7% per year, perpendicular diffusivity increased 1.2% per year, and magnetization transfer ratio decreased 0.9% per year. The T2 relaxation time changed more rapidly than diffusion tensor imaging indices and magnetization transfer ratio but had higher within-participant variability. Magnetization transfer ratio in the corpus callosum and supratentorial brain declined at an accelerated rate in progressive MS relative to relapsing-remitting MS. Power analysis yielded reasonable sample sizes (on the order of 40 participants per arm or fewer) for 1- or 2-year trials.
Longitudinal changes in whole-brain and tract-specific diffusion tensor imaging indices and magnetization transfer ratio can be reliably quantified, suggesting that small clinical trials using these outcome measures are feasible.
The presence of transient lesions involving the splenium of the corpus callosum (SCC) has been described in patients with encephalitis or encephalopathy of varied etiology. We have termed it RESLES (reversible splenial lesion syndrome).
To describe 3 additional patients (2 encephalitis, 1 hypoglycemia) and review the literature to define this syndrome, its etiology, presentation, prognosis, and possible pathophysiological mechanisms.
Search of the MEDLINE database from 1966 through 2007. English language article titles and abstracts were screened and the appropriate articles reviewed. Additional articles cited by original references were also reviewed.
RESLES is caused by antiepileptic drug withdrawal, infection, high-altitude cerebral edema (HACE), or metabolic disorders (hypoglycemia and hypernatremia). Complete resolution after a variable lapse is the rule. Clinical presentation is nonspecific, without evidence of callosal disconnection syndromes. Neuroimaging shows a nonenhancing, round-shaped lesion centered in the SCC that disappears after a variable lapse. Diffusion studies reveal DW hypersignal with low ADC values, suggestive of cytotoxic edema. Only HACE-related cases and 1 patient with pregabalin withdrawal showed high ADC values, consistent with vasogenic edema.
RESLES is a distinct clinicoradiological syndrome of varied etiology and benign course except in those patients with an underlying severe disorder.