November 2025
In this VETgirl online veterinary continuing education blog, Dr. Missy Carpentier, DACVIM (Neurology) details a step-wise process to management of feline seizures. Learn the common differentials, diagnostic workup, and treatment options for seizures in our feline friends!

By Missy Carpentier, DVM, DACVIM (Neurology)
Minnesota Veterinary Neurology, Columbus, MN

Common Differentials and Management of Feline Seizures

Cats commonly present to both general practice and referral centers due to seizures. For a long time, it was thought that if a cat has a history of seizures, then they must have something sinister occurring in their brain. Luckily, we now know that this is not often the case. Though we rarely see true idiopathic or genetic epilepsy in cats due to the decreased presence of purebred cats in practice, it is important for veterinarians to know that up to 22-54% of cats presenting with seizures are secondary to epilepsy of unknown cause (EUC), and in most cases we are successfully able to manage their seizures.

The clinical picture of epileptic cases varies considerably, but the ultimate goal for every patient is the same – good seizure control with a good quality of life. This discussion will summarize my general approach to the feline epileptic patient, reviewing the initial evaluation, differential diagnosis, diagnostics, and treatment.

Signalment

It is important to know that a complete work up should be recommended for any cat that has seizures, regardless of age. It is, however, important to pay attention to the age and breed of the cat to help you start to think about possible differentials for the seizures. Remember, until you officially neurolocalize your patient based on the neurologic examination, you cannot finalize your list of differentials!

Some top differentials that you should consider for a cat less than 1 year of age with seizures would include metabolic disease (a portosystemic shunt), degenerative, developmental, toxin, or inflammatory brain disease. For an older cat (greater than 10 years of age) that is presenting for seizures, neoplasia or a cerebrovascular accident need to be high on your differential list, but these are not the only differentials! For purebred cats, you need to have developmental or degenerative high on your list.

History

The history that the owners provide is invaluable. One of the first obstacles that you face with a seizure patient is whether or not that patient is truly experiencing seizures. There is a wide variety of seizures, and unfortunately, many of them are not the classic tonic-clonic seizure that makes identification easy, and this is particularly true for cats. Cats can present with any type of seizure, however, two of the most common types of seizures in cats include focal and orofacial, and these can sometimes be difficult to identify. That is why it is extremely important that the owners describe the seizure to you in detail, to identify the type of seizure they possibly are having, and to recognize any signs that may not be related to a seizure. I commonly see patients presenting with a complaint of seizures, but after gathering further information from the owners, they are diagnosed with neck pain, vestibular disease, syncope, etc. It is also important to recognize that an owner may give you a perfect description—or, even better, have a video of the episode in question—and you still are left uncertain if it truly is seizure activity or not. In these cases, often times it is best to use the clinical signs that are present before or after the suspect seizure to help you identify if the episode in question was a possible seizure.

Physical and Neurologic Examination

A complete physical and neurologic evaluation should be performed on every patient. If there are abnormal physical examination findings, then diagnostics based on those findings should be pursued. In regards to the neurologic evaluation, a cat is always going to be a cat and makes things a little tricky. Do the best you can, but it is highly unlikely that you will be performing a complete neurologic evaluation AND THAT’S OKAY! Special attention should be paid to any other signs of forebrain dysfunction (e.g., circling, head pressing, cortical blindness, conscious proprioception deficits).

Many animals will have an abnormal neurologic evaluation in the post-ictal period. Normally if you have abnormal neurologic examination findings, it makes epilepsy of unknown cause less likely, but a lot of cats will have mentation changes, visual deficits, ataxia or paresis for hours or sometimes days after seizure activity. So don’t necessarily give the cat a bad prognosis if they have neurologic deficits immediately after a seizure, but if the deficits remain after 1-2 days, or worsen, then other causes besides epilepsy of unknown cause need to be considered. One abnormal neurologic examination finding that wouldn’t be due to the post ictal state would be spinal hyperesthesia – if spinal hyperesthesia is present inflammatory disease of the nervous system should be high on your differential list.

After you have completed your full evaluation, you will then neurolocalize your patient. If a patient is presenting for seizures, you know that the forebrain is involved. The importance of the neurologic evaluation is to be sure that other parts of the nervous system aren’t involved, in which case your neurolocalization would change from forebrain to multifocal. Based on where you neurolocalize your patient will then allow you to form an appropriate list of differentials.

Differential

I cannot stress the importance of coming up with a list of differentials for your seizure patients, because this will help guide your diagnostic recommendations. The International League Against Epilepsy publishes new etiologic classifications for epilepsy every couple of years and often the veterinary field will make modifications on our classification based on these changes. I don’t worry so much about the classification, just use what works best for you to come up with a good list of differentials. For example, if you are used to using the DAMNIT-V scheme, below is a list of some differentials that you may want to consider for a feline patient with seizures. This is by no means an exhaustive list of causes of seizures.

Diagnostics

Recommended diagnostics for the epileptic patient will largely depend on your differentials, but at a minimum these patients should be receiving complete blood cell counts, full chemistry profiles, urinalysis, and a liver function test (either bile acids or ammonia). From there, further testing that you may include would be thoracic and abdominal radiographs, abdominal ultrasound, brain MRI +/- cerebrospinal fluid analysis. It is important to stress that in our feline patients, a complete neurologic work-up, including a brain MRI and CSF evaluation, is recommended if indicated and safe to do so.

Controlling the Epileptic Patient

In 2015, the ACVIM published a Consensus on seizure management in dogs and I follow those same guidelines for when to start an AED in cats. The consensus states that an AED should be started if:

  • Identifiable structural lesion present or prior history of brain disease or TBI
  • Acute repetitive seizures or status epilepticus (SE) (ictal >5 minutes or >/=3 or more generalized seizures within a 24-hours period)
  • >/= 2 or more seizure events within a 6-month period
  • Prolonged, severe or unusual postictal periods

If an underlying disease for the patient is found – i.e., inflammatory brain disease – then treating the underlying disease in conjunction with AED’s is needed. If epilepsy of unknown cause is diagnosed, it is important for the owners to understand that there is no cure. We do our best to control the frequency, duration, and severity of seizures with AEDs.

Treatment is normally started with one anticonvulsant medication and other medications are added if needed. I try and “max out” the current AED that a patient is receiving prior to adding in a 2nd AED as long as the patient is handling the medication well. When I am considering if I have “maxed out” a drug, I am considering the patients drug blood level, blood work, side effects, owners’ ability to handle the side effects, and cost. For example, though levetiracetam is a great medication to choose for cats, most owners have a very difficult time giving a medication three times a day. A frustrated owner of an epileptic patient is not something that we want, though out of fear and uncertainty it often does come with the territory. That being said, if we can provide as much information and minimize their concerns and frustrations early on, it will increase our overall ability to help these patients in the long-term.

I often get asked what is considered good seizure control and the answer is that it is very case dependent. If I see a patient that has been having seizures once a week and I can get their frequency down to 1 seizure every 1-2 months, I am happy. On the flip side, if I have a patient that is only having seizures every 2-3 months but their seizures last up to 5 minutes and they are dangerously aggressive to the owner in the post-ictal state, then I will not be satisfied and I will strive for better seizure control.

I find that it is good information to let the owners know that as long as we get good seizure control, which 44% of cats with EUC will have good control with phenobarbital, then the overall life-expectancy of their beloved pet shouldn’t be altered.

AED Options

When you start a patient on anti-seizure or anti-epileptic medications, we have three goals:

Below is a chart of the most commonly used feline AED’s, the recommended starting dose of these AED’s, drug blood level monitoring, and side effects. Once I have chosen the AED for the patient, I normally start at the listed dose and make further dosage adjustments based on the drug blood levels and side effects.  Remember, every seizure case is different, and you should expect that you are going to need to adjust your treatment plan many times until you find what works for them.

References

  1. Pakozdy A, Halasz P, Klang A. Epilepsy in cats: Theory and practice. J Vet Intern Med. 2014;28:255-263.
  2. Podell M, Volk HA, Berendt M, et al. 2015 ACVIM small animal consensus statement on seizure management in dogs. J Vet Intern Med. 2016;30:477-490.
  3. Wahle AM, Bruhschwein A, Matiasek K et al. Clinical characterization of epilepsy of unknown cause in cats. J Vet Intern Med. 2014;28:182-188.

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