Feline Epilepsy: Diagnostic Approach and Treatment

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-11

Key Takeaways

• Feline epilepsy affects 1-3% of cats, with idiopathic epilepsy typically presenting in younger cats (around 3.5 years) compared to secondary causes (around 8 years). Focal seizure semiology, including facial twitching and behavioral automatisms, is common and can be mistaken for other disorders.
• A comprehensive diagnostic work-up is mandatory for all seizuring cats, including a minimum database (CBC, biochemistry, bile acids, urinalysis, infectious disease serology), brain imaging (MRI), and cerebrospinal fluid analysis to rule out structural, metabolic, and inflammatory causes.
• Idiopathic epilepsy is a diagnosis of exclusion, confirmed only after structural brain lesions, metabolic disturbances, and CNS inflammatory/infectious diseases are ruled out via advanced diagnostics.
• Phenobarbital remains the most established first-line antiepileptic drug (AED) for feline epilepsy, with therapeutic serum concentrations monitored every 6-12 months after stabilization. Levetiracetam is a common adjunctive therapy for refractory cases due to its favorable safety profile and lack of hepatic enzyme induction.
• Treatment initiation is typically considered after two or more seizures within six months, cluster seizures, status epilepticus, or prolonged postictal periods, aiming for seizure freedom or significant reduction with minimal adverse effects.
• The evidence base for AED efficacy and safety in cats is limited, with most studies being small and having a high risk of bias; only two blinded randomized controlled trials exist, necessitating careful owner communication regarding expected outcomes and monitoring.

Seizures affect approximately 1 to 3% of the general feline population, making them one of the most common neurologic presentations in small animal practice. This article provides a structured diagnostic approach to the seizuring cat and outlines current treatment options for confirmed epilepsy, with emphasis on decision criteria, antiepileptic drug selection, and monitoring strategies. The content is directed at practicing veterinarians who manage seizure disorders in cats and who require a framework for distinguishing idiopathic epilepsy from structural and reactive causes before committing to long-term therapy.

The diagnostic and therapeutic challenges in feline epilepsy differ from those in canine patients. Cats frequently exhibit focal seizure semiology that may be mistaken for other behavioral or gastrointestinal disorders, and the historical literature has underappreciated the prevalence of primary epilepsy in this species. A systematic work-up is therefore recommended for every cat presenting with a first seizure episode, and treatment decisions should follow established diagnostic criteria instead of empirical trial therapy. This article excludes reactive seizures and structural brain diseases from detailed therapeutic discussion, although their recognition is integral to the diagnostic pathway presented here.

At a Glance

Classification of Feline Seizures

Seizure classification in cats follows the same tripartite framework used in dogs: primary (idiopathic) epilepsy, structural epilepsy, and reactive seizures. Primary epilepsy is defined as recurrent seizures with no identifiable underlying structural brain lesion or metabolic disturbance. Structural epilepsy arises from intracranial pathology such as neoplasia, inflammatory disease, vascular events, or trauma. Reactive seizures occur in response to extracranial metabolic or toxic derangements and are not considered epilepsy in the strict sense.

The historical assumption that primary epilepsy is rare in cats has been revised. Contemporary reviews recognize this syndrome at a lower frequency than in dogs, but it is no longer considered uncommon. This shift has important therapeutic implications, because cats with idiopathic epilepsy may respond well to antiepileptic medication and carry a more favorable prognosis than those with structural disease. The diagnostic challenge lies in distinguishing these categories reliably, particularly when neurologic examination findings are normal between episodes.

Focal seizure semiology is particularly common in cats and may include facial twitching, ear or tail movements, pupillary changes, and behavioral automatisms such as excessive salivation or vocalization. Generalized tonic-clonic seizures occur as well, but the clinician should maintain a high index of suspicion for focal onset with secondary generalization. A detailed video recording of the event, obtained from the owner, often provides diagnostic information that rivals the historical description.

Diagnostic Approach to the Seizuring Cat

The diagnostic evaluation of a cat with recurrent seizures proceeds through defined stages. Signalment and seizure pattern provide the first layer of discrimination. Cats with idiopathic epilepsy tend to be younger, with a mean age around 3.5 years, whereas cats with secondary seizure disorders typically present at approximately 8 years of age. This age distinction is a statistical tendency instead of a diagnostic rule, and older cats can still develop idiopathic epilepsy.

Physical and neurologic examinations follow. A normal interictal neurologic examination supports the possibility of idiopathic epilepsy but does not exclude structural disease. Conversely, persistent neurologic deficits, particularly those lateralizing to one side of the brain, increase the likelihood of an intracranial lesion. Fundic examination is mandatory, as retinal changes may reveal evidence of systemic infectious, inflammatory, or hypertensive disease.

The minimum laboratory database includes a complete blood count, serum biochemistry panel, pre- and postprandial bile acid measurements, urinalysis, and serologic testing for feline leukemia virus, feline immunodeficiency virus, feline infectious peritonitis, and Toxoplasma gondii. A case series of 30 cats with recurrent seizures found structural brain disease in all cats for which a definitive diagnosis was reached, with nonsuppurative meningoencephalitis and feline ischemic encephalopathy being the most common diagnoses. This historical finding underscores the importance of pursuing advanced imaging instead of presuming idiopathic epilepsy on clinical grounds alone.

Advanced imaging with magnetic resonance imaging (MRI) is recommended for all cats presenting for initial evaluation of seizures. Cerebrospinal fluid analysis should be performed when inflammatory or infectious disease is suspected, provided imaging has excluded conditions that would make collection unsafe. The combination of MRI and cerebrospinal fluid analysis is essential for detecting structural lesions that would otherwise be missed.

Criteria for Diagnosing Idiopathic Epilepsy

Idiopathic epilepsy in cats is a diagnosis of exclusion. The criteria require recurrent seizures with no identifiable structural brain lesion on MRI, no metabolic abnormalities on laboratory testing, and no evidence of inflammatory or infectious central nervous system disease on cerebrospinal fluid analysis. The diagnostic approach outlined in the veterinary literature emphasizes that this diagnosis should be reached only after a complete work-up, not on the basis of signalment and normal interictal examination alone.

Electroencephalography (EEG) has a limited but evolving role in feline epilepsy diagnosis. Interictal EEG may identify epileptiform discharges that support a diagnosis of epilepsy, but a normal interictal recording does not exclude the condition. Ictal video-EEG monitoring, where available, provides the most definitive characterization of seizure type and origin, and is particularly valuable for presurgical evaluation in drug-resistant cases. The conceptual framework of the epileptogenic zone, comprising symptomatogenic, irritative, seizure-onset, structurally abnormal, and functional deficit zones, guides this advanced diagnostic work.

Treatment Principles and Evidence Base

The evidence base for antiepileptic drug therapy in cats is less robust than in dogs. A systematic review of antiepileptic drugs in feline epilepsy identified 40 studies reporting clinical outcomes, of which only two were classified as blinded randomized controlled trials. The majority of studies had high overall risk of bias, described small feline populations, and used unclear diagnostic criteria with short treatment or follow-up periods. This evidence limitation should inform clinical conversations with owners about expected outcomes and the need for careful monitoring.

Phenobarbital remains the most established first-line antiepileptic drug in cats, supported by the longest track record of clinical use. Levetiracetam is commonly employed as an add-on agent for refractory cases and has a favorable safety profile in cats. Other agents used in canine epilepsy may be less suitable in cats due to species-specific toxicities, and current formulary and label references must be consulted before prescribing any antiepileptic medication. The selection of a specific drug should consider seizure frequency and severity, comorbid conditions, owner compliance factors, and the anticipated duration of therapy.

Treatment is typically initiated after a cat has experienced multiple seizures within a defined period, or after a single severe or prolonged seizure event. The threshold for starting antiepileptic medication should be discussed with the owner, and the decision documented in the medical record. Once therapy begins, the goal is seizure freedom or an acceptable reduction in seizure frequency with minimal adverse effects, achieved at the lowest effective drug concentration.

Antiepileptic Drug Selection in Cats

The choice of an antiepileptic drug (AED) in cats is guided by seizure frequency, severity, underlying diagnosis, and the owner's capacity for long-term commitment. Phenobarbital remains the most widely used first-line agent, supported by decades of clinical experience and a comparatively favourable safety profile in this species. Levetiracetam has gained popularity as an adjunctive agent, particularly when hepatic enzyme induction is undesirable or when sedation is poorly tolerated. The evidence base for both drugs in cats is limited, with a systematic review identifying only two blinded randomised controlled trials among forty included studies, and the majority of reports carrying a high risk of bias systematic review of antiepileptic drugs' safety and effectiveness in feline epilepsy.

Treatment should begin after a definitive or probable diagnosis of epilepsy is reached and after structural and reactive causes have been excluded. A single seizure does not mandate lifelong therapy. Most clinicians initiate AEDs when a cat has experienced two or more seizures within a six-month period, cluster seizures, status epilepticus, or a postictal period that is prolonged or distressing. The decision is also influenced by seizure semiology. Focal seizures with secondary generalization are common in cats and may be more amenable to control than generalized tonic-clonic events, although comparative data are lacking.

Phenobarbital

Phenobarbital is the first-line AED for most cats with epilepsy. Its efficacy is well documented in clinical practice, and serum drug monitoring is widely available. The drug is a hepatic enzyme inducer, and this effect is clinically relevant in cats, although less pronounced than in dogs. Serial serum biochemistry is recommended to detect hepatotoxicity, which is uncommon but potentially serious.

Serum phenobarbital concentrations should be measured three to four weeks after treatment initiation or dose adjustment, at the trough point, and then every six to twelve months once the cat is stable. The therapeutic reference interval for cats is generally cited as 15 to 45 micrograms per mL, although individual cats may be controlled at lower concentrations and some require concentrations above this range. Dose adjustments should be made incrementally, and each change should be followed by a repeat trough measurement after steady state is reached. Clinical signs of phenobarbital toxicity include sedation, ataxia, and polyphagia, which are most prominent during the first two weeks of therapy and often diminish with continued use. Persistent sedation beyond this period warrants a serum concentration check and possible dose reduction.

Levetiracetam

Levetiracetam is a reasonable choice as an adjunctive agent when phenobarbital alone provides inadequate control or causes unacceptable adverse effects. Its mechanism of action is distinct, binding to the synaptic vesicle protein SV2A, and it does not induce hepatic enzymes. This makes it attractive in cats with concurrent hepatobiliary disease or in those receiving multiple medications. The drug is renally excreted, and dose adjustment is required in cats with reduced renal function.

Levetiracetam has a wide therapeutic index in cats, and adverse effects are generally mild and transient. Sedation and inappetence are the most commonly reported signs, and they often resolve within the first week of treatment. Serum monitoring is not routinely performed, as a clear therapeutic interval has not been established in cats. The drug is available in both immediate-release and extended-release formulations, and the dosing interval differs accordingly. Owners should be counselled that a missed dose may precipitate breakthrough seizures more rapidly than with phenobarbital, given the drug's shorter half-life.

Other Antiepileptic Drugs

Zonisamide is used occasionally in cats, but its safety profile is less well characterized than that of phenobarbital or levetiracetam. Hepatotoxicity and renal tubular acidosis have been reported, and routine monitoring of liver enzymes, urea, and creatinine is advised. Gabapentin and pregabalin have limited evidence for seizure control in cats and are more commonly used for neuropathic pain. Potassium bromide is poorly tolerated in cats, with a high incidence of bronchial irritation and pneumonitis, and is rarely recommended. Benzodiazepines are used for emergency seizure control but are not suitable for chronic maintenance therapy due to tolerance and dependence.

The table below summarizes the key considerations for AED selection in cats.

Monitoring the Treated Cat

Regular re-evaluation is essential for any cat receiving long-term AED therapy. The minimum database at each visit includes body weight, a complete neurologic examination, and a serum biochemistry panel. Body weight is particularly important in cats, as weight loss can alter drug distribution and necessitate dose adjustment. Neurologic examination findings should be compared with the baseline assessment, and any deterioration should prompt investigation for progressive structural disease instead of being attributed to the epilepsy itself.

Serum biochemistry is used to detect drug-related adverse effects. In cats receiving phenobarbital, liver enzyme activities should be assessed at each monitoring visit. Mild increases in alanine aminotransferase activity are common and may reflect enzyme induction instead of hepatocellular injury. Marked or progressive increases, or concurrent increases in bilirubin or bile acids, warrant further investigation. Levetiracetam does not require routine serum biochemistry monitoring beyond assessment of renal function, and zonisamide monitoring should include liver enzymes and renal parameters.

Seizure frequency should be documented at every visit. Owners should be asked to maintain a seizure diary that records the date, time, duration, and semiology of each event, as well as any potential provoking factors. This diary is the primary tool for assessing treatment response. A reduction in seizure frequency of 50% or more is often cited as a successful outcome, but the goal of therapy is the lowest possible seizure frequency with the fewest adverse effects. Complete seizure freedom is achievable in a proportion of cats but should not be promised at the outset.

Refractory Epilepsy and Referral

Cats that continue to seize despite therapeutic serum concentrations of phenobarbital, or that experience unacceptable adverse effects, are considered to have refractory epilepsy. The definition is not standardized, but failure of two appropriately dosed AEDs, used sequentially or in combination, is a practical threshold. Before labeling a cat as refractory, the clinician should confirm that the diagnosis of epilepsy is correct, that drug concentrations are within the therapeutic interval, and that the owner is administering medication reliably. Poor owner compliance is a common cause of apparent treatment failure.

Referral to a veterinary neurologist should be considered when seizures remain uncontrolled despite combination therapy, when the diagnosis is uncertain, or when advanced imaging is required. Advanced diagnostic techniques, including ictal video monitoring, interictal electroencephalography, and functional MRI, may be used to identify the epileptogenic zone in cats with suspected focal epilepsy diagnostic techniques to detect the epileptogenic zone in dogs and cats. These modalities are not widely available and are typically reserved for cats being evaluated for epilepsy surgery, which remains an uncommon procedure in feline practice.

Prognosis and Owner Communication

The prognosis for cats with idiopathic epilepsy is generally favourable, with many cats achieving good seizure control on phenobarbital monotherapy. However, the evidence base is limited, and outcomes vary widely between individuals. Owners should be counselled that epilepsy is a chronic condition requiring lifelong therapy and that the goal of treatment is seizure reduction, not necessarily cure. The financial and time commitments of regular monitoring should be discussed openly before treatment begins.

Cats with structural epilepsy have a more guarded prognosis, which depends on the underlying lesion. The diagnostic work-up should therefore be completed before committing to long-term AED therapy, as a treatable structural cause may change both the treatment plan and the prognosis diagnostic evaluation of cats with seizure disorders. Euthanasia is sometimes elected in cats with severe, refractory epilepsy or progressive structural disease, and this outcome should be acknowledged as a legitimate endpoint in difficult cases.

Recognized Complications and Early Detection

Treatment failure in feline epilepsy usually reflects one of several identifiable problems. The most common is subtherapeutic drug exposure, either from underdosing, poor owner compliance, or altered metabolism. Cats metabolise phenobarbital more slowly than dogs, and steady state may require three to four weeks to reach. A cat that continues seizing during the loading phase is not necessarily refractory. Measure a serum trough concentration after at least two weeks of stable dosing before declaring failure.

Hepatic enzyme induction and hepatotoxicity are the principal concerns with chronic phenobarbital use. Early detection relies on serial serum biochemistry, with particular attention to alkaline phosphatase and alanine aminotransferase trends. A rising bile acid profile or clinical signs of lethargy, anorexia, or icterus warrant dose reduction or a switch to an alternative agent. Phenobarbital-associated hepatotoxicity is less common in cats than dogs, but it remains a recognized cause of morbidity.

Levetiracetam carries a lower risk of hepatic injury, but its short half-life in cats creates a different failure mode. Dosing intervals that are too long produce breakthrough seizures in the hours before the next dose. Owners may report a pattern of seizures at predictable times of day. Serum drug concentration monitoring is less established for levetiracetam than for phenobarbital, so the diagnosis of this failure mode rests on the temporal pattern and a trial of shortened dosing intervals.

Other complications include paradoxical excitation, sedation that impairs quality of life, and drug interactions. Bromide, occasionally used as an add-on, carries a substantial risk of bronchial irritation and pneumonitis in cats and is poorly tolerated by many individuals. Early signs include coughing, gagging, or increased respiratory effort, and the drug should be discontinued if these appear.

Common Errors and Corrective Actions

Less experienced clinicians frequently mistake post-ictal behavior for ongoing seizure activity. Cats may circle, hide, vocalise, or show facial twitching for hours after a generalized event. Video documentation from the owner is the most reliable discriminator, and asking for it should be routine.

A second error is treating a single seizure as epilepsy without a diagnostic work-up. The evidence base shows that structural brain disease is a common cause of feline seizures, and a complete evaluation including brain imaging and cerebrospinal fluid analysis is recommended for all cats presenting for initial evaluation of seizures. Skipping this step risks missing meningioma, inflammatory disease, or vascular events that require specific therapy.

A third error is escalating doses too quickly. Phenobarbital takes weeks to reach steady state, and dose increases based on a single breakthrough seizure can produce toxicity before efficacy is fairly assessed. The converse error, failing to increase a clearly subtherapeutic dose, is equally common. A serum concentration below the reference interval with ongoing seizures justifies a dose increase, provided the clinician has confirmed compliance.

Finally, clinicians sometimes abandon a drug after a single adverse effect instead of managing the side effect. Transient sedation in the first two weeks of phenobarbital therapy is expected and usually resolves. Distinguishing this from persistent toxicity requires patience and a repeat examination instead of an immediate drug change.

Limitations of the Current Evidence

The feline epilepsy literature is less robust than the canine literature. A systematic review of antiepileptic drugs in cats identified only two blinded randomised controlled trials, with most studies offering a high overall risk of bias, small populations, unclear diagnostic criteria, and short follow-up periods. This means that much of what is recommended in practice rests on extrapolation from dogs and humans, clinical experience, and small case series.

Expert opinion still differs on several points. The threshold for starting antiepileptic therapy in cats with infrequent seizures is debated. Some clinicians treat after a single generalized seizure, while others wait for two or more events. The optimal first-line agent is also contested, with phenobarbital and levetiracetam both having advocates. The systematic review evidence supports phenobarbital as a reasonable first choice, but the quality of that evidence is limited.

The diagnosis of idiopathic epilepsy in cats remains a diagnosis of exclusion. The criteria used in dogs have been adapted for cats, but the lower prevalence of confirmed idiopathic epilepsy in cats means that the pretest probability of finding a structural lesion is higher. Clinicians should maintain a lower threshold for advanced imaging in cats than in dogs, particularly in older animals, where the mean age of cats with secondary seizure disorders is approximately 8 years compared with 3.5 years for idiopathic epilepsy.

Referral and Escalation

Referral to a veterinary neurologist is indicated when seizures continue despite therapeutic serum concentrations of a first-line drug, when the diagnosis is uncertain after a complete work-up, or when advanced imaging is not available in practice. Specialist centers offer video-EEG monitoring, which can characterize the epileptogenic zone and guide surgical planning in drug-resistant cases. Surgical resection of a structural lesion, such as a meningioma, may be curative and should be discussed when imaging identifies a resectable abnormality.

Laboratory involvement extends beyond routine biochemistry. A reference laboratory should be used for serum phenobarbital concentration measurement, and the same laboratory should be used for serial monitoring to reduce inter-assay variability. Bile acid testing, thyroid assessment, and infectious disease serology may be indicated based on signalment and clinical findings.

Regulatory reporting is rarely required for feline epilepsy, but clinicians should be aware that some infectious causes of seizures, such as rabies, are reportable in many jurisdictions. The World Organization for Animal Health maintains international standards for the surveillance and reporting of notifiable diseases, and local requirements should be checked when a zoonotic or regionally significant cause is suspected. Professional practice resources from organizations such as the AVMA can clarify reporting obligations in the United States.

Troubleshooting Table

Frequently Asked Questions

How should I manage a cat with cluster seizures when the owner cannot afford advanced imaging?

When advanced imaging is not feasible, the diagnostic focus shifts to a thorough history, physical and neurologic examination, and minimum database including hematology, serum biochemistry, and urinalysis. Infectious disease testing and bile acid measurement can identify common reactive causes. If these are unremarkable and the cat meets age and phenotype criteria, a working diagnosis of presumed idiopathic epilepsy is reasonable, and treatment can begin. The owner must understand that structural disease remains possible and that seizures may progress or change character. Re-evaluate the diagnostic plan if seizure pattern, neurologic status, or response to treatment deteriorates. The diagnostic approach to recurrent seizures in cats can be tailored to available resources while preserving safety.

What documentation is essential for managing a feline epilepsy patient?

Maintain a seizure diary recording date, time, duration, semiology, and any precipitating events. Document each antiepileptic drug, dose, and serum concentration alongside the date of measurement. Record body weight at every visit, as dose adjustments in cats are frequently weight driven. Note neurologic examination findings, including interictal abnormalities, at each recheck. Written communication with the owner should include the treatment goal, expected adverse effects, and a clear emergency plan for cluster seizures or status epilepticus. Consistent records allow objective assessment of treatment response and support decisions about dose changes or add-on therapy. The ACVIM consensus statements provide a framework for structured monitoring and documentation.

When should I consider levetiracetam as a first-line drug instead of phenobarbital?

Levetiracetam is a reasonable first-line choice when hepatic disease, poor owner compliance with twice-daily dosing, or concerns about phenobarbital's adverse effect profile are present. Phenobarbital remains the most established first-line agent in cats, with a longer evidence base for efficacy. Levetiracetam offers a wider safety margin and fewer drug interactions, but its shorter half-life requires more frequent dosing. The systematic review of antiepileptic drugs in feline epilepsy found limited high-quality comparative data, so drug selection often rests on individual patient factors and owner capacity. If the cat is young and otherwise healthy, phenobarbital is usually preferred. If the cat is older or has concurrent disease, levetiracetam may be the safer initial choice.

How do I explain the difference between idiopathic epilepsy and structural epilepsy to an owner?

Explain that idiopathic epilepsy means the brain is structurally normal and the seizures arise from a functional electrical disturbance with no identifiable cause. Structural epilepsy means a physical lesion, such as a tumor, inflammation, or scar, is triggering the seizures. Emphasize that MRI and cerebrospinal fluid analysis are the only reliable ways to distinguish these in most cases. Owners should understand that a normal neurologic examination between seizures does not exclude structural disease, particularly in older cats. The prognosis differs meaningfully, with idiopathic epilepsy often manageable long term, while structural epilepsy may progress despite treatment. The diagnostic approach to recurrent seizures in cats relies on this distinction to guide therapy and prognostic counseling.

What should I do when a cat continues to seize despite therapeutic phenobarbital concentrations?

First confirm the serum concentration is genuinely in the therapeutic range and that the owner is administering the drug consistently. Assess for intercurrent illness, particularly hepatic or renal disease, that may alter drug metabolism. Re-evaluate the diagnosis, as structural disease may have been missed if imaging was not performed. Consider adding levetiracetam as an adjunctive agent, as it has a favourable safety profile in cats and is commonly used for refractory cases. If seizures remain uncontrolled, referral for advanced imaging and electroencephalography should be pursued, as presurgical evaluation may identify a resectable epileptogenic zone. The evidence base for add-on therapy in cats is limited, so dose adjustments should be made cautiously with close monitoring.

How should I counsel an owner about the long-term cost of managing feline epilepsy?

Be transparent that epilepsy management is a lifelong commitment with predictable recurring costs. These include twice or thrice daily medication, periodic serum drug concentration monitoring, and regular veterinary rechecks. Phenobarbital is generally inexpensive, while levetiracetam is more costly, and this difference may influence drug selection. Emergency visits for cluster seizures or status epilepticus add substantial expense. Discuss the possibility of dose escalation over time and the potential need for add-on therapy in refractory cases. Owners should also consider the cost of advanced diagnostics if not already performed. A realistic financial plan, discussed early, reduces the risk of treatment abandonment and supports consistent long-term care.

Related Clinical & Scientific Guides

• Feline Hepatic Lipidosis: Nutritional and Medical Management
• Canine Respiratory Infection: Diagnostic Approach and Treatment
• Canine Respiratory Virus: Diagnostic and Management Considerations

References and Further Reading

• The seizuring cat. Diagnostic work-up and therapy.. 2009.
• Recurrent seizures in cats: Diagnostic approach - when is it idiopathic epilepsy?. 2018.
• Seizures and epilepsy in cats.. 2014.
• Systematic review of antiepileptic drugs' safety and effectiveness in feline epilepsy.. 2018.
• Diagnostic techniques to detect the epileptogenic zone: Pathophysiological and presurgical analysis of epilepsy in dogs and cats.. 2016.
• Diagnostic evaluation of cats with seizure disorders: 30 cases (1991-1993).. 1997.
• ACVIM Consensus Statements. Journal of Veterinary Internal Medicine.
• MSD Veterinary Manual, Professional Edition. MSD Veterinary Manual.
• American Veterinary Medical Association Practice Resources. American Veterinary Medical Association.

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This article is educational professional reference material for veterinary audiences. It is not a substitute for veterinary diagnosis, individual clinical judgment, current product labeling, or applicable regulatory requirements.