Topics in Companion Animal Medicine

Published by Elsevier
Print ISSN: 1938-9736
Publications
Although veterinary clinicians commonly rely on panels of laboratory tests with individual results flagged when abnormal, care should be taken in interpreting normal test results as well. There are several examples of this in evaluating patients with endocrine disease. The finding of a normal leukogram (absence of a stress leukogram) can be indicative of adrenal insufficiency in dogs, and this disorder can be especially elusive when there are no overt indicators of mineralocorticoid deficiency. Cats with hyperthyroidism can have normal serum thyroid hormone concentrations, normal hematocrits, and normal serum concentrations of creatinine despite the presence of disease that affects these parameters. A normal serum phosphorus concentration, in the face of azotemia, isosthenuria, and hypertension can point a clinician toward a diagnosis of primary hyperaldosteronism rather than primary renal disease. A normal serum parathyroid hormone concentration in the face of hypercalcemia is inappropriate and can indicate the presence of primary hyperparathyroidism. Similarly, hypoglycemia accompanied by a normal serum insulin concentration can be found in cases of hyperinsulinism. These normal findings in abnormal patients, and their mechanisms, are reviewed.
 
Acromegaly, or hypersomatotropism, results from chronic, excessive secretion of growth hormone in the adult animal. The anabolic effects of growth hormone are exerted through the intermediary hormone, insulin-like growth factor 1, which is produced in the liver under the influence of growth hormone. Feline acromegaly is caused by a pituitary adenoma that secretes excessive amounts of growth hormone. Characteristic effects of excessive growth hormone secretion include the development of diabetes mellitus and growth of the acral segments of the body (jaw, extremities, skull, etc.). Acromegaly occurs in older, predominately male cats and is often associated with diabetes mellitus. Other clinical signs include stridor, enlargement of the jaw and extremities, lean weight gain, and organomegaly (heart, liver, kidney, etc.). Diagnosis is made by documentation of increased levels of growth hormone or insulin-like growth factor (or both) and demonstration of a pituitary mass via magnetic resonance imaging or computed tomography. The most effective treatment to date has been radiation therapy. Prognosis is fair to good with proper treatment.
 
At one time, it was estimated that the majority of dogs and cats in the United States received 90% or more of their nutrition from complete and balanced commercially prepared foods, and this estimate was reaffirmed in a 2004 survey. However, 4 years and several pet food and treat recalls later, fewer pet owners are feeding commercial pet food products exclusively and more are asking questions and looking for alternatives. As in any market-driven economy, there are many more alternative diets and food products available today from which pet owners may select. A difficult to measure but growing number of clients are feeding homemade diets that provide 100% of their pet's nutrition, while a larger number are feeding a combination of products, treats, and home prepared meals. Most practitioners can attest to this increase in their client's interest in homemade meals and to having insufficient knowledge to assist them. At a time when motivated clients are considering homemade for their pets as an alternative, veterinarians are less than adequately versed in canine and feline nutrition and dietary options. The article addresses the two most important health issues concerning pet owners and veterinarians about homemade diets: nutritional integrity and food safety.
 
Complementary and alternative medicine can be defined as the diagnosis, treatment, and/or prevention that complements mainstream medicine, satisfying a demand not met by orthodoxy and diversifying the conceptual framework of medicine. Acupuncture is being used much more commonly now as a sole or integrative modality in veterinary medicine and can play a large role in management of inflammation and chronic pain. Western medical etiology, pathophysiology, diagnosis, and treatment should be considered before applying acupuncture. This article describes the evolving biomedical basis of acupuncture analgesia and gives the practitioner an overview of how acupuncture can be performed in a medical setting.
 
Acute pancreatitis in dogs is a potentially reversible condition, but in severe forms it can cause systemic and local complications. These complications are driven by the cytokine, complement, and kinin systems, with the roles of these systems along with other substances such as nitric oxide being increasingly studied. The intestinal tract and altered pancreatic microcirculation also contribute greatly to the perpetuation of disease. Diagnosis remains difficult, because the true diagnostic utility of the current tests available is problematic to establish. Further understanding of the pathophysiology of this disease has opened up new areas of research into optimal treatments. In particular, the role of enteral nutrition has been the focus of much attention, and current recommendations are to feed earlier in the disease than previously thought.
 
Acute management of hypercalcemia and hypocalcemia is an important part of small-animal emergency practice. In addition to hypercalcemia of malignancy and hyperparathyroidism, vitamin D toxicosis is becoming more common in companion animals as new and improved rodenticides and human pharmaceutical preparations (vitamin D analog skin creams) become more available. This article provides complete details regarding the emergency management of life-threatening hypercalcemia with focus on vitamin D intoxication. At the other end of the spectrum, hypocalcemic emergencies, such as periparturient hypocalcemia (eclampsia), may be less common but are often life threatening. This article contains guidelines for the emergency management of hypocalcemia. In summary, the urgent care of calcium disorders in small animals is reviewed.
 
The American Psychiatric Association estimates that 3-7% of US school-aged children exhibit attention-deficit/hyperactivity disorder (ADHD). Adderall(®) (amphetamine dextroamphetamine) and a variety of brand names and generic versions of this combination are available by prescription to treat ADHD and narcolepsy. Both immediate and sustained release products are used as are single agent amphetamine medication. Knowing the exact agent ingested can provide information of dose labeled and length of clinical effects. These drugs are used off label by college students for memory enhancement, test taking ability, and for study marathons. These agents are DEA Schedule II controlled substances with high potential for abuse. For humans with ADHD or narcolepsy, standard recommended dosage is 5-60mg daily. Amphetamine and its analogues stimulate the release of norepinephrine affecting both α- and β-adrenergic receptor sites. α-Adrenergic stimulation causes vasoconstriction and an increase in total peripheral resistance. β-Adrenergic receptor stimulation leads to an increase in heart rate, stroke volume, and skeletal muscle blood flow. Clinical signs of Adderall(®) overdose in humans and dogs include hyperactivity, hyperthermia, tachycardia, tachypnea, mydriasis, tremors, and seizures. In addition, Adderall intoxication in dogs has been reported to cause hyperthermia, hypoglycemia, hypersegmentation of neutrophils, and mild thrombocytopenia. Diagnosis can be confirmed by detecting amphetamine in stomach contents or vomitus, or by positive results obtained in urine tests for illicit drugs. Treatment is directed at controlling life-threatening central nervous system and cardiovascular signs. Seizures can be controlled with benzodiazepines, phenothiazines, pentobarbital, and propofol. Cardiac tachyarrhythmias can be managed with a β-blocker such as propranolol. Intravenous fluids counter the hyperthermia, assist in maintenance of renal function, and help promote the elimination of amphetamine and its analogues. Prognosis after poisoning with Adderall(®) depends upon the severity and duration of clinical signs at presentation. Differential diagnoses that should be considered in cases of suspected amphetamine overdose are any other agents that can cause central nervous system stimulation, tremors, and seizures. This article discusses our present understanding of Adderall(®) intoxication and examines 3 dogs presented to our practice after ingestion of large amounts of the drug.
 
On account of their unique anatomy, physiology, natural history, ecology, and behavior, rattlesnakes make ideal subjects for a variety of different scientific disciplines. The prairie rattlesnake (Crotalus viridis) in Colorado was selected for investigation of its relationship to colonies of black-tailed prairie dogs (Cynomys ludovicianus) with regard to spatial ecology. A total of 31 snakes were anesthetized and had radiotransmitters surgically implanted. In addition, at the time of their capture, all snakes underwent the following: (1) they had bacterial culture taken from their mouths for potential isolation of pathogenic bacteria; (2) similarly, they had cloacal bacterial cultures taken to assess potentially harmful bacteria passed in the feces; and (3) they had blood samples drawn to investigate the presence of any zoonotic agents in the serum of the snakes. The results of the study and their implications are discussed here. Traditionally, a low incidence of bacterial wound infection has been reported following snakebite. Nevertheless, the oral cavity of snakes has long been known to house a wide variety of bacterial flora. In our study, 10 different bacterial species were isolated from the mouths of the rattlesnakes, 6 of which are capable of being zoonotic pathogens and inducing human disease. More studies are necessary to see why more rattlesnake bites do not become infected despite the presence of such pathogenic bacteria. The results of fecal bacteria isolated revealed 13 bacterial species, 12 of which can cause disease in humans. Of the snakes whose samples were cultured, 26% were positive for the presence of the pathogen Salmonella arizonae, one of the causative agents of reptile-related salmonellosis in humans. It has long been reported that captive reptiles have a much higher incidence than wild, free-ranging species. This study shows the incidence of Salmonella in a wild, free-ranging population of rattlesnakes. In addition, Stenotrophomonas maltophilia was isolated. This bacterium is associated with wound and soft tissue infections that can lead to sepsis, endocarditis, meningitis, and peritonitis. In addition, this bacterium has been increasingly implicated as an opportunistic pathogen to humans during pregnancies, hospitalizations, malignancies and chemotherapy, chronic respiratory diseases, and presurgical endotracheal intubation. Furthermore, S. maltophilia has an intense resistance to broad-spectrum antibiotics, the results of our study showed the bacterium was resistant to multiple antibiotics. Our results indicate that anyone working with snake feces, dead skin, or their carcasses must follow reasonable hygiene protocols. Rattlesnakes tested for West Nile antibodies had positive results but these were invalidated owing to possible cross-reactivity with other unknown viruses, interference with snake serum proteins, and the fact that the test was not calibrated for rattlesnake serum. Still, the interesting implication remains, should we be regularly testing these animals as sentinels against potentially zoonotic diseases. The results of this study clearly show the value of veterinarians in a multidisciplinary study of this sort and the particular skill set they can offer. Veterinarians must get involved in conservation studies if the biodiversity of the planet is to be preserved.
 
A 12-year-old female spayed domestic short-haired cat presented for lethargy, poor hair coat, alopecia, difficulty walking, and mild polyuria/polydipsia. The cat's skin tore easily in the neck area during routine restraint for blood draw. Physical examination, blood analysis, and ultrasound imaging were all consistent with pituitary-dependent hyperadrenocorticism (PDH) with secondary insulin-resistant diabetes mellitus, which was nonketotic. Insulin therapy, fluids, and diet change were initiated for the diabetes mellitus and the owner reported improvement in clinical signs although the blood glucose measurements remained elevated. Surgical repair of the torn skin was successful. Although a guarded prognosis was given to the owner because of an advanced stage of hyperadrenocorticism, and the limited treatment options currently available for feline PDH, trilostane was agreed on as an initial therapeutic option. The day trilostane was to be initiated, the cat presented with dyspnea and the owner chose to euthanize. Because of the rarity of hyperadrenocorticism disease in the cat, permission was obtained by the owner for a necropsy to confirm suspected PDH as the underlying cause for insulin resistance and skin fragility syndrome.
 
Polyurethane adhesives are found in a large number of household products in the United States and are used for a variety of purposes. Several brands of these expanding wood glues (those containing diphenylmethane diisocyanate [MDI]) have the potential to form gastrointestinal (GI) foreign bodies if ingested. The ingested adhesive forms an expanding ball of glue in the esophagus and gastric lumen. This expansion is caused by a polymerization reaction using the heat, water, and gastric acids of the stomach. A firm mass is created that can be 4-8 times its original volume. As little as 2oz of glue have been reported to develop gastric foreign bodies. The obstructive mass is reported to form within minutes of ingestion of the adhesive. The foreign body can lead to esophageal impaction and obstruction, airway obstruction, gastric outflow obstruction, mucosal hemorrhage, ulceration, laceration, perforation of the esophageal and gastric linings, and death. Clinical signs following ingestion include anorexia, lethargy, vomiting, tachypnea, and abdominal distention and pain, and typically develop within 12 hours. Clinical signs may depend upon the size of the mass. If left untreated, perforation and rupture of the esophagus or stomach can occur. The glue mass does not stick to the GI mucosa and is not always detectable on abdominal palpation. Radiographs are recommended to confirm the presence of the "glue-ball" foreign body, and radiographic evidence of the obstruction may be seen as early as 4-6 hours following ingestion. Emesis is contraindicated owing to the risk of aspiration of the glue into the respiratory tree or the subsequent lodging of the expanding glue mass in the esophagus. Likewise, efforts to dilute the glue and prevent the formation of the foreign body through administration of liquids, activated charcoal, or bulk-forming products to push the foreign body through the GI tract have proven ineffective. Even endoscopy performed to remove the foreign body has been shown to be unreliable. The safest, most effective, and successful therapy is surgical intervention to remove the GI foreign body. If performed early enough, complete recovery of the animal can be expected. Differential diagnoses for polyurethane adhesive ingestion include any potential cause of GI obstruction. The public is largely unaware of the hazards that ingestion of this product may produce. Public education efforts are needed to inform pet owners about the hazards of these glues and the overall importance of providing our companion animals with safe, poison-free environments.
 
Eyelid surgery plays an important role in the management of a variety of ophthalmic diseases. Surgery on the adnexa and eye is routinely performed on an anesthetized patient. Minor procedures, such as conjunctival biopsy, may be performed in an awake patient using only topical anesthesia. Retrobulbar, peribulbar, and local anesthesia are less commonly used in general practice; however, they can provide significant advantages when used appropriately. Advantages to local anesthesia/sedation include being able to perform some ophthalmic procedures without having to place the patient under general anesthesia, ability to maintain the patient under a lighter plane of general anesthesia, improved postoperative comfort, and potentially smoother recoveries from general anesthesia. This article reviews this author's current indications and techniques for regional anesthesia as an adjunct to eyelid surgery in dogs.
 
Substantial improvements in therapeutic options for companion animal reproduction and gynecologic emergencies have been made over the last decade. New, alternative drug treatments, with fewer side effects and improved efficacy, are available. This has widened the spectrum of therapeutic possibilities for diseases that were previously treated only by surgical intervention. New drugs are available for estrus induction and pregnancy termination, as well as for the treatment of pyometra. This review summarizes the pharmacology and toxicology of reproductive agents currently in use for contraception, pyometra, dystocia, eclampsia, premature labor, agalactia, mastitis, metritis, and prostatic disorders, and compares their efficacy and safety with newer agents. Drug use and exposure during pregnancy and lactation, and subsequent risks to the fetuses, are also explored, with emphasis on antimicrobials, antifungals, anthelminthics, anesthetics, and vaccinations.
 
Feline inappropriate elimination is the number one behavioral reason for relinquishment of cats to shelters and has historically been the most commonly reported feline problem addressed by behavior professionals. Veterinarians are hence challenged to uncover the underlying motivation for this behavior so that an accurate diagnosis can be made and an effective treatment plan implemented. Before a behavioral diagnosis can be made, underlying medical disease must be addressed, making a comprehensive physical evaluation imperative. After all medical issues have been addressed, a behavior diagnoses list is made based on detailed historical information obtained from the cat owner. A distinction is first established between marking and inappropriate toileting, according to elimination postures described by the owner and the social relevance of the sites of inappropriate eliminations. Next, inadequacies of the litter box management are identified and subsequent aversions and preferences, including litter box aversion, substrate aversion, location aversion, substrate preference, and location preference, can be diagnosed. The practitioner should be cognizant of the fact that anxiety from the environment and social conflict may play a major role in both marking and inappropriate toileting behaviors. Once both the medical and behavioral diagnoses are established, a treatment plan catered to the individual cat, owner, and household environment can be formulated. This should include acceptable forms of marking when indicated, appropriate litter box management and hygiene, reduction of environmental stressors, including resolution of social conflict in multicat households, proper treatment and restricted access to soiled areas, pheromone application, and, when indicated, anxiolytic drug therapy.
 
The complete blood count is one of the basic building blocks of the minimum database in veterinary medicine. Over the past 20 years, there has been a tremendous advancement in the technology of hematology analyzers and their availability to the general practitioner. There are 4 basic methodologies that can be used to generate data for a complete blood count: manual methods, quantitative buffy coat analysis, automated impedance analysis, and flow cytometric analysis. This article will review the principles of these methodologies, discuss some of their advantages and disadvantages, and describe some of the hematology analyzers that are available for the in-house veterinary laboratory.
 
Tests of canine cognition are now receiving much deserved attention. Not only are dogs excellent models for human anxiety-related conditions and those involving brain aging, but how dogs learn and problem solve are interesting stand-alone topics. A number of factors can affect learning at the molecular level including stress or distress, factors that affect olfaction, effects of breed and nutritional factors including that may affect available brain energy. This review provides an overview of how these factors may affect baseline learning and brain aging.
 
Working as a veterinarian in remote field locations can be physically and intellectually challenging. A collaborative multi-disciplinary approach is often required for successful data collection. Technologies and methodologies frequently need to be modified to work in these harsh field environments. This article will describe a collaboration in southeastern Mongolia collecting blood for sera analytes and physiologic data from Eurasian Black Vulture (Aegypius monachus) chicks during a tagging operation.
 
In the United States, pet foods are subject to regulation at both the federal and the state levels. The US Food and Drug Administration has jurisdiction over all animal feeds (including pet foods, treats, chews, supplements, and ingredients) in interstate commerce, which includes imported products. Many states adopt and enforce at least in part the Association of American Feed Control Officials Model Bill and Model Regulations for Pet Food and Specialty Pet Food. Thus, all pet foods in multi-state distribution are subject to a host of labeling requirements covering aspects such as product names, ingredient lists, nutrient content guarantees, and nutritional adequacy statements. Ingredients must be GRAS (generally recognized as safe) substances, approved food additives, or defined by Association of American Feed Control Officials for their intended use. Pet food labels may not bear claims that are false or misleading or that state or imply use for the treatment or prevention of disease. Pet foods that are found to be adulterated or misbranded may be subject to seizure or other enforcement actions.
 
Brachycephalic airway syndrome is a common finding in brachycephalic breeds. A combination of primary and secondary changes can progress to life-threatening laryngeal collapse. Early recognition of primary anatomic abnormalities that include stenotic nares, elongated soft palate, and hypoplastic trachea would allow the clinician to make early recommendations for medical and surgical management, which can improve the quality of life in affected animals.
 
Because the airway extends from the oral or nasal cavity to the alveoli, airway compromise or respiratory disease has numerous manifestations. Complications can be encountered in both the upper and lower airways and include a vast range of problems including laryngeal paralysis, collapsing trachea, pneumonia, pulmonary edema, pneumothorax, intrathoracic masses and diaphragmatic hernias. Anesthesia can cause further complications because anesthetic drugs and equipment can exacerbate or even cause airway difficulties and respiratory compromise. When anesthetizing patients with respiratory disease or airway complications, the choice of the actual anesthetic drugs is not necessarily dictated by the presence of respiratory compromise, but rather by the overall health of the patient. The choice of anesthetic technique (e.g., method of induction, method of intubation, use of positive-pressure ventilation, etc.), on the other hand, is often critical.
 
Alimentary lymphoma is one of the most commonly diagnosed neoplasms of the cat. The incidence of this disease has increased significantly over the past 15 years during the post-feline leukemia era. Despite the common prevalence of this disease, appropriate diagnosis and treatment can be challenging. There are two main forms of feline alimentary lymphoma: the small-cell (lymphocytic, well-differentiated, low-grade) lymphoma variety and the large-cell (lymphoblastic, high-grade) lymphoma variety. These two diseases are related; however, each presents its own diagnostic and therapeutic challenges. Additionally, it can be difficult to differentiate these malignancies from other nonneoplastic diseases such as inflammatory bowel disease and other chronic inflammatory conditions of the gastrointestinal tract. The purpose of this article is to tackle the challenges of this allusive disease with a step-by-step approach to diagnosis, staging, and therapy.
 
Wolbachia is an obligate intracellular endosymbiont and likely mutualist living within the heartworm Dirofilaria immitis and a number of other filarial nematodes in the family Onchocercidae. The bacterial infection is passed from worm to worm transovarially; the organisms are in ovarian cells, the developing microfilariae, and multiply and persist in all later developmental stages through the mosquito and into the next host. Besides being present in the ovaries of the adult worms, they also are present in large numbers within the hypodermal tissues of the nematode. It is now know that these bacteria that were first observed in heartworms more than 30 years ago are actually related to similar Wolbachia bacteria that are found in arthropods. Wolbachia is an alpha-proteobacteria, and this group includes a number of important arthropod-transmitted bacterial agents of dogs and cats: Rickettsia rickettsii, R. felis, Anaplasma platys, Ehrlichia canis, E. chaffeensis, and E. ewingii. Alpha-proteobacteria are also important as obligate intracellular mutualists in plants in which they are responsible for nitrogen fixation. Recent work on the treatment of heartworms in dogs with doxycycline stems from related work with the human filarial nematode Onchocerca volvulus that causes river blindness in people.
 
This review examines the biology of ticks and tick-borne infections in the United States. The most common tick-borne diseases in dogs and cats are discussed. We demonstrate that there is much interest in tick-borne infections at the level of the lay public (pet owners), describe trends in the distribution and prevalence of tick-borne infections in the United States, summarize some issues in understanding the degree of ill health due to tick-borne infections, and suggest some avenues for research that would clarify these issues.
 
Aminobisphosphonates are a class of drugs effectively used for the management of pathologic skeletal conditions in people, most notably hormonally mediated osteoporosis and cancer-associated bone metastases. Based on their physicochemical properties, aminobisphosphonates concentrate within areas of active skeletal remodeling and exert protective bone biologic effects through the induction of osteoclast apoptosis. Given the similar mineral composition and cellular components of bone tissue shared among mammals, it would be expected that aminobisphosphonates should also be effective in managing malignant bone diseases in dogs and cats. The first half of this review article briefly summarizes the general properties of aminobisphosphonates including their pharmacology, mechanism of action, and potential adverse side effects. The second half of this review focuses on the clinical utility of aminobisphosphonates and measures of response in dogs and cats diagnosed with malignant skeletal tumors.
 
Many perioperative pain management protocols for cats and dogs are overly complex, some are ineffective, and still others expose patients to unnecessary risk. The purpose of this article is to provide clinicians with a basic understanding of the pathophysiology of perioperative pain and a working knowledge of the principles of effective therapy. First, the concept of multimodal analgesic therapy is discussed. Next, the pathophysiology of perioperative pain and the clinical pharmacology of the major classes of analgesic drugs are reviewed. And last, a simplified approach to managing perioperative pain in cats and dogs is presented.
 
Pet foods on the market that are contaminated or otherwise present a health risk to humans or animals may be subject to a recall under US Food and Drug Administration (FDA) regulations. Legally, all recalls are "voluntary," but there is little incentive for companies to refuse a request by FDA to conduct a recall. While the firm does the bulk of the work, FDA oversees all aspects of a recall to help ensure that violative product is swiftly removed from the market. A recent new federal law will require FDA to improve its abilities to detect outbreaks of pet food-borne illness, respond to a contamination incident, and communicate with industry and the public on the matter of recalls. Veterinarians play a key role in detecting and reporting pet food-borne illness.
 
General anesthesia may be necessary for patients with significant disease processes such as renal disease or hepatic disease. A basic understanding of the effects of general anesthetics on these organs and the anticipated problems of renal and hepatic impairment on the anesthetic process is necessary to optimize conditions for patients with renal or hepatic disease. Patient preparation, drug selection, and monitoring strategies will be discussed for patients with renal and liver disease.
 
Current standards of care in veterinary medicine dictate an adequate level of pain control for our patients. Effective pain control uses a proactive, multimode approach that starts with preoperative medications, includes the anesthetic protocol selected, and continues into the postoperative period. A basic understanding of the physiology of pain assists in selecting those agents and modalities best suited for individual patients. Analgesic drug selection and local anesthesia are both integral parts of pain control when performing surgery in the oral cavity. Local (regional) anesthesia plays an important part in the pain control of oral surgical patients. Regional anesthetic techniques are used for many common oral procedures, including extractions, periodontal flap surgery, treatment of traumatic injuries of the oral cavity, tumor removal, palatal surgery, periodontal therapy, and root canal therapy. This presentation will cover strategies for analgesia and the techniques and materials used in local/regional anesthesia in the oral cavity. Anatomic landmarks and guidelines for effective regional blocks will be covered.
 
Cerebral blood flow may be altered in anesthetized patients, and this could be detrimental to patients with intracranial disease. Cerebral blood flow is autoregulated and held constant over a mean arterial pressure range of 50 to 150 mm Hg. Changes in cerebral blood volume are reflected by cerebral blood flow, whereas intracranial pressure varies directly with cerebral blood volume. Cerebral blood flow is also under chemical regulation and varies directly with arterial carbon dioxide tension over the range of 25 to 70 mm Hg. A reduction in arterial oxygen tension to below 60 mm Hg also dramatically increases cerebral blood flow. Changes in both arterial carbon dioxide and oxygen tensions are common in anesthetized patients. Furthermore, anesthetic drugs can alter cerebral blood flow. Injectable anesthetics, except ketamine, tend to preserve cerebral blood flow. Inhalant anesthetics may be associated with cerebral vasodilation, increased cerebral blood flow, and raised intracranial pressure. However, low concentrations of inhalant anesthetics combined with controlled ventilation are effective in preventing exacerbation of raised intracranial pressure. Factors affecting cerebral blood flow should be considered before anesthetizing patients with intracranial disease.
 
Shelter medicine presents a unique challenge that is different from veterinary medicine in a hospital setting. The shelter and/or mobile unit environment requires special anesthetic considerations to support high-volume spay-neuter and feral animal programs with high quality of anesthesia/immobilization for surgery and diagnostic procedures. The anesthetic protocols can be tailored to the needs of each specific shelter setting. An ideal shelter anesthesia protocol will have a wide safety margin for animals of all ages. The protocol must also be effective, economical, and easy to use with a small volume for injection, have rapid on- and off-set with a reasonable surgical duration after a single administration, be predictable, and possess perioperative analgesic properties. An anesthesia protocol with a combination of tiletamine-zolazepam and dexmedetomidine in combination with an opioid fits the criteria of the shelter anesthesia protocols. These combinations possess rapid induction of immobilization, unconsciousness, and muscle relaxation with an anesthesia duration of 30 to 45 minutes. Specific and nonspecific reversal agents are also available to facilitate recovery. This article describes the use of these anesthetic protocols as well as monitoring support for these protocols.
 
Anesthetic management of orthopedic patients could vary from normal routine management to more challenging critical management depending on the state in which the patient is presented. Multimodal pain management strategies incorporating opioids, which are the mainstay drugs for pain management, along with adjunctive drugs like local anesthetics (eg, lidocaine), dissociative anesthetics (eg, ketamine), and alpha-2 agonists (eg, dexmedetomidine), could improve overall patient comfort and help prevent establishment of chronic pain pathways. Also, use of local nerve blocks can prevent nociception right at the point of origin. Orthopedic patients with multiple organ traumas like head injuries, spinal injuries, pulmonary fat embolism, compartment syndrome, or thoracic injuries are high-risk patients in which any life-threatening organ pathology should be addressed before the patient is put under general anesthesia. Interactions of various drugs like antibiotics and neuromuscular blocking agents used in the perioperative period in orthopedic patients should warrant a careful consideration with respect to their interactions with each other and other anesthetic drugs used.
 
Anesthetic complications appear relatively rare, though recent work suggests they are more common in cats than dogs. Current estimates indicate that approximately 0.11% (1 in 895 anesthetics) of healthy cats die of an anesthetic-related death, which is more than twice as frequent as has been recently reported in dogs (0.05% or 1 in 1849). Most of these deaths occurred in the postoperative period. A number of risk factors have been associated with death, including patient health status, age, weight, and procedure type and urgency. Endotracheal intubation and fluid therapy have been reported to be associated with increased odds of anesthetic death in cats and may reflect higher risk techniques in cats compared with dogs. Monitoring patient pulse and the use of a pulse oximeter were also recently reported to be associated with reduced risk of anesthetic death. These data can help veterinarians care for their patient under anesthesia and address greater attention to patient assessment and management before anesthesia, as well as more careful fluid administration and patient monitoring during and after anesthesia, which could reduce perioperative complications in cats.
 
The increase in the use of magnetic resonance imaging (MRI) for diagnostic use in companion animals has increased the demand for anesthesia support in a strong magnetic environment. In many instances, this may necessitate anesthesia being provided by individuals that are unfamiliar with MRI and the hazards associated with it. The objective of this article is to describe the conditions and hazards associated with a strong magnetic field, review considerations for safe and effective anesthetic management of patients during an MRI, and promote close collaboration and communication between personnel in an effort to insure staff awareness and safety. This report describes conditions that exist for the superconducting high field strength magnets, 1.0, 1.5, and 3.0 Tesla, that are commonly used for clinical imaging of companion animals. Many of these same safety and anesthesia considerations can be applied to any MRI facility.
 
This review is a general discussion of common zoonotic infections of companion animals in the United States. Microbes, routes of transmission, and risks to immunocompromised persons are discussed. The primary focus of this article is dogs and cats, although zoonoses of avian, rodent, and rabbit companion animals are discussed in brief. An awareness of zoonoses will allow veterinarians and physicians to collaboratively prevent transmission and treat clinical disease in both human and veterinary patients.
 
A well-designed and executed diagnostic approach to patients with bleeding disorders is critical to determine disease etiology and guide therapeutic measures. This systematic process begins with a comprehensive history and physical examination, followed by laboratory tests of primary hemostasis (platelet enumeration, platelet function testing, and von Willebrand factor assays), secondary hemostasis (prothrombin time, activated partial thromboplastin time, activated clotting time, and individual factor deficiencies), and fibrinolysis (fibrinogen activity, thrombin time, fibrin degradation products, D-dimers), dependent on the clinical picture. Equally valuable are proper specimen collection, handling, and storage methods, which provide reliable and reproducible result interpretation. This review will emphasize the common diagnostic tools and blood sampling techniques important to the workup of hemostatic diseases as well as provide an overview of advanced clinical and research methods and equipment available to assist our bleeding veterinary patients, including thromboelastography/thromboelastometry, calibrated automated thrombogram, and the thrombin-antithrombin assay.
 
Epileptogenesis is the process by which a normal brain develops into an epileptic brain. There are 3 distinct phases of epileptogenesis-the latent period before seizures occur, the occurrence of recurrent seizures, and in about 30% of patients, the development of refractory epilepsy. Understanding the basic epileptic circuit abnormalities associated with recurrent seizures via aberrations in glutamate, gamma-aminobutyric acid, and ligand- and voltage-gated ion channel activity can help the small-animal practitioner understand the mechanism of action of the antiepileptic drugs currently used for dogs and cats for new-onset and refractory epilepsy. Understanding the latest research results and theories about the pathophysiology of the latent period of epileptogenesis, where recurrent seizures have not yet developed, would help the practitioner understand possible target areas for future treatments to treat epilepsy by preventing it rather than just symptomatically preventing recurrent seizures. The current areas of focus of research on the latent period include neurodegeneration, neurogenesis, axonal sprouting, glial cell activation, invasion of inflammatory cells, angiogenesis, and subclinical alteration of ligand- and receptor-gated ion channels.
 
This review discusses leishmaniasis in cats and dogs in the United States. Leishmaniasis is endemic in Foxhound populations in the United States and is still being characterized in this group. Pathophysiology, clinical signs, transmission, immunology, and treatment are examined in this review. Leishmaniasis is an emergent zoonosis of great public health significance.
 
Reports of loss-of-efficacy (LOE) events in dogs infected with Dirofilaria immitis despite adherence to accepted prophylaxis regimens with a macrocyclic lactone anthelmintic are attracting considerable attention. It is crucially important to distinguish among several possible causes for these LOE reports, one of which is the evolution of resistance to these drugs in heartworms. We review here recent evidence at the molecular level that supports the hypothesis that parasites derived from LOE cases have experienced a strong selection event and that these populations are characterized by very high frequencies of single-nucleotide polymorphisms in a D. immitis gene encoding a P-glycoprotein transporter, comprised of homozygous guanosine residues at 2 locations ("GG-GG" genotype). Furthermore, an infected dog adopted to Canada from the southern United States harbored a microfilarial population that was insensitive to very high doses of macrocyclic lactones and was characterized by a high frequency of the GG-GG genotype associated with LOE cases. We propose that this case be defined as a drug-resistant heartworm infection and suggest that a simple assay for the existence of resistant parasites is a 7-day microfilariae suppression test, which can be performed in a veterinary clinic as part of an effort to document the geographic distribution of this phenotype.
 
Blood coagulation is a complex and highly coordinated process that is constantly altered and impacted by procoagulant and anticoagulant "players." It is vital that these components work in concert to maintain a balance to keep coagulation in check. Several important endogenous anticoagulants will be discussed in this review including tissue factor pathway inhibitor, antithrombin, protein C, and protein S in origin, structure, mechanism of action, effects of deficiency, and current knowledge in veterinary medicine.
 
Over the past 2 decades, the number of antiepileptic drugs (AEDs) available to veterinarians has grown exponentially. Coupled with this increase is the ability to rapidly and accurately diagnose underlying brain disease with readily accessible magnetic resonance imaging. As a result, the veterinary community is attuned to the need for early treatment intervention. As more treatment choices become available, the unrelenting questions still arise are when should treatment begin, which initial drug therapy is best for our patients, when should treatment changes be considered, and finally, what are the advantages that newer drugs provide for our patients. The purpose of this chapter is to review decision-making strategies for AED therapy, provide an overview of the applicability of current AED available, and present information on the therapeutic advances in epilepsy.
 
Thrombosis or thromboembolism are significant concerns in companion animals and can be associated with cardiac, metabolic, neoplastic disease processes or can be one manifestation of inflammatory, infectious, and neoplastic disease conditions. Options for thromboprophylaxis available for clinical use in small animal patients are very limited, with heparin (primarily unfractionated, but more recently low-molecular-weight forms) and aspirin predominating. Controlled studies evaluating the use of these drugs are few, but there is some limited evidence for efficacy in prevention of formation of thrombi. Use of the vitamin K antagonist warfarin has been described, but the narrow therapeutic window has resulted in a high rate of serious adverse events. In human patients, the efficacy of aspirin, heparins, and vitamin K antagonists is well documented in a variety of thrombotic conditions, but there are significant limitations to each of these options. These limitations have prompted the search for new alternatives, some of which are now in wide clinical use in humans. Although the use of some of the drugs discussed here has not yet been described in veterinary patients at risk for thrombosis, many of these agents have been evaluated experimentally in dogs, cats, or both. These new thromboprophylactic agents may soon be beneficial in management of small animal patients at risk for thrombosis.
 
Feline handling in the veterinary hospital is important to protect both people and cats. Restraint has been used to enable us to perform our duties as veterinarians. With increased knowledge of feline behavior and how cats react to fear, newer information provides us with safer handling techniques. With safer and more respectful handling based on understanding the nature of cats and their communication, we can improve feline health care in our hospitals, the human-animal-veterinarian bond, and the welfare of both cats and people. This article explains important aspects of feline communication and how our actions affect cats. By understanding the cat, we can improve our handling techniques to prevent fear and pain for our feline patients, and thus make our veterinary practices more feline friendly and safer for our clients, their cats, and veterinary staff.
 
Arterial and venous blood gases provide useful information regarding pulmonary function as well as acid-base balance. The goal of this article is to discuss the collection of blood gases, common errors in analysis, and what information can be gleaned from a blood gas analysis.
 
Clinicians are frequently presented with laboratory test results that are not consistent with preconceived expectations for a given case. One important reason for such results is the occurrence of preanalytical errors. In this article preanalytical errors are discussed in 2 parts. The first part covers the steps of sample collection, preparation, and transportation, in which preanalytical errors often occur. This part would be most useful if read in full before collecting a sample. The second part of this article includes a systematic review of preanalytical errors divided according to individual analytes or parameters or, when appropriate, groups of analytes and parameters that represent the same biological system. This part will hopefully serve the clinician as a quick and user friendly guide for identification of possible pitfalls when presented with unexpected laboratory test results for a given case. This article is limited to errors that can affect the complete blood count, chemistry, and coagulation panels.
 
The technique of fine-needle biopsy (fine-needle aspiration or fine-needle fenestration) for cytologic evaluation can be extended to many sites beyond the traditional lymph node and skin. Intra-abdominal, intrathoracic, and bone lesions can be easily and rapidly evaluated cytologically. Percutaneous fine-needle aspiration and fine-needle fenestration are useful, accurate, and inexpensive techniques with a rapid turnaround time, and outpatient applicability. For most pets, these minimally invasive techniques do not require anesthesia or analgesia. Although risks are inherent with any invasive procedure, complications are uncommon even with visceral and intrathoracic fine-needle biopsy. Attention to appropriate technique and close patient monitoring minimize the morbidity and improve the diagnostic utility. The low cost, low risk, minimal invasiveness, and high diagnostic yield make fine-needle biopsy particularly attractive to clients. In combination with ultrasound guidance and newer staining techniques, these diagnostic procedures are invaluable to the veterinary clinician.
 
Dogs and cats are commonly exposed to infectious disease agents. The following article is an update on the most common infectious disease assays used in small animal practice. In some situations, results of pathogen-specific molecular diagnostic assays can be used to assist the practicing veterinarian in the management of patients with infectious diseases. However, with some infectious disease agents, the assays are positive in healthy and ill animals and can be falsely negative and so the predictive values of the assays vary.
 
Increasing numbers of cats are living to become elderly and they commonly develop behavioral changes. The objectives of this article are to consider the possible causes and prevalence of behavioral problems in pet cats, to describe how cognitive dysfunction syndrome (CDS) typically presents, and how its diagnosis and management are often complicated by the concurrent presence of multiple interacting disease processes. The most frequently reported behavioral problems in old cats are loss of litter box training and crying out loudly at night. The most common causes of these problems are CDS, osteoarthritis, systemic hypertension (commonly secondary to chronic kidney disease or hyperthyroidism), hyperthyroidism (even without hypertension), deafness, and brain tumors. These conditions all occur frequently in older cats, many of which suffer from a number of concurrent interacting conditions. Owners and veterinary surgeons often mistake these for "normal aging changes," so many treatable conditions are neglected and go untreated. Almost one third of cats 11 to 14 years of age develop at least one geriatric-onset behavior problem that appears to relate to CDS, and this increases to over 50% for cats 15 years of age or older. For optimum management of elderly cats with behavioral problems, all interacting conditions need to be diagnosed and addressed concurrently with management for CDS.
 
Top-cited authors
Kevin T Fitzgerald
  • Alameda East Veterinary Hospital, Denver Colorado, USA
Autumn P Davidson
  • University of California, Davis
Jessica K Rychel
  • Veterinary Emergency & Rehabilitation Hospital
Valeria Scorza
  • Colorado State University
Sahatchai Tangtrongsup
  • Chiang Mai University