Evaluating a Cat with Seizures: History, Examination and Initial Diagnostic Work-Up

A cat presented with seizures may appear completely normal between episodes. That does not make the initial consultation any less important. Signalment, history, and a thorough physical and neurological examination can reveal clues to systemic disease, multifocal neurological involvement or an intracranial disorder and help determine which investigations are warranted. 

Signalment Can Change the Differential List 

Age and breed should be considered from the outset. 

In juvenile cats, anomalous, metabolic, and genetic conditions deserve particular attention. Reported brain malformations include hydrocephalus, porencephaly, and lissencephaly^{[1],[2],[3],[4]}. 

Age can also influence concern for structural disease. In adult cats, seizure onset after 7 years of age was associated with increased odds of structural epilepsy. Pedigree cats were also more likely to have a structural underlying cause. These findings can help guide clinical suspicion but should not be used in isolation to establish a diagnosis^[4]. 

History Often Provides the First Diagnostic Clues^[4] 

A detailed history should extend beyond the seizure itself. 

Ask about changes between episodes, including altered interaction with people or other animals, increased or decreased vocalisation, reduced grooming, inappropriate toileting, head pressing or compulsive pacing and circling. These behavioural changes may indicate forebrain disease. 

Visual abnormalities and signs suggestive of hemineglect syndrome may also be relevant. A cat that consistently eats from only one side of its bowl, for example, may be showing reduced awareness of stimuli on one side of the body. 

Systemic history can point towards an extracranial cause. Recent weight loss, gastrointestinal signs, inappetence, polyphagia or polyuria/polydipsia may indicate metabolic, infectious or neoplastic disease. A history of known or suspected toxin exposure and previous head trauma should also be recorded because both may be relevant to seizure development. 

Diet deserves specific attention, particularly in juvenile patients or cats with a restricted or unusual dietary history. Thiamine deficiency is a recognised cause of seizures and may be associated with poorly processed or heat-treated diets, sulphite-preserved foods or diets containing thiaminase, such as raw fish. 

Vaccination status, travel history and indoor/outdoor lifestyle should also be documented. 

Examine More Than the Nervous System^[4] 

Every cat presenting with epileptic seizures should undergo a thorough physical and neurological examination. 

Physical examination may reveal systemic illness associated with metabolic, infectious, or multifocal disease. Blood pressure measurement is recommended because hypertension can contribute to neurological disease. Fundic examination can provide additional information, including evidence of uveitis or chorioretinitis, retinal atrophy or retinal haemorrhage associated with hypertension. 

The neurological examination should assess^[4]: 

• Mental status and behaviour 
• Posture and gait 
• Proprioception 
• Spinal reflexes 
• Cranial nerves 
• Neck and back pain 

Abnormal neurological findings that cannot be explained by forebrain disease alone raise concern for multifocal central nervous system involvement and support the need for further investigation. Abnormal interictal neurological examinations have also been associated with structural epilepsy in cats. 

Timing matters. Ataxia, visual or hearing deficits, polydipsia, polyphagia, and behavioural changes such as aggression can occur during the postictal period. If possible, neurological examination should therefore be repeated after the postictal phase has resolved^[4]. 

Start With Metabolic Screening 

Haematology and serum biochemistry should be used to investigate extracranial causes, including hepatic or renal encephalopathy, hypertriglyceridemia, polycythaemia vera and severe anaemia. 

Depending on the clinical picture, further testing may include pre- and postprandial bile acids, ammonia, thyroid hormones, and serum electrolytes. Glucose and calcium abnormalities, as well as disturbances involving magnesium, sodium, and potassium, can also be associated with seizures. 

This initial work-up helps determine whether the seizure may be reactive and whether investigation for an intracranial cause is warranted. 

Clinical Bottom Line 

The first seizure consultation should not focus only on describing the episode. Signalment, a targeted history, complete physical and neurological examination, and appropriate metabolic screening together establish the clinical direction. Careful assessment at this stage can identify systemic clues, recognise neurological abnormalities that warrant further investigation, and help determine the next diagnostic step.

References:

1. Gradner G, Kaefinger R, Dupré G. Complications associated with ventriculoperitoneal shunts in dogs and cats with idiopathic hydrocephalus: a systematic review. Journal of veterinary internal medicine. 2019 Mar;33(2):403-12. https://academic.oup.com/jvim/article-pdf/33/2/403/66659325/jvim15422.pdf
2. Kawasaki Y, Tsuruta T, Setogawa Y, Sakamoto H. Hydrocephalus with visual deficits in a cat. Journal of veterinary medical science. 2003;65(12):1361-4. https://www.jstage.jst.go.jp/article/jvms/65/12/65_12_1361/_pdf
3. Kang MH, Ho YK, Park HM. Long-term management of seizure disorders associated with porencephalic cysts in two cats. Pak Vet J. 2014 Jun 1;34(2):276-78. http://pvj.com.pk/pdf-files/34_2/276-278.pdf
4. Sivolapenko D, Lowrie M. Epileptic seizures in cats: practical approaches to diagnosis. Journal of Feline Medicine and Surgery. 2026 Feb;28(2):1098612X251407905. https://journals.sagepub.com/doi/pdf/10.1177/1098612X251407905