Epilepsy is a condition that describes recurring seizures in cats that may occur days, hours, or months apart. Epilepsy can affect small animals (cats and dogs) just as it can affect humans.

What are epileptic seizures?

Seizures are caused by excessive electrical activity in the brain, random nerve impulses that can cause loss of consciousness and cause uncontrolled, uncoordinated contractions of some or most of the muscles in the body. There are other symptoms such as salivation, drooling, urination and defecation. As the cat recovers from a seizure, there will be disorientation, behavioral changes, staggering, and a period of gradual recovery in the post-drug withdrawal period. Seizures can be classified as generalized (grand mal seizures) or partial (focal seizures).

This article discusses recurrent epilepsy as a feline disease, describes the different types seen in cats, and explains the veterinary approach to treating feline epilepsy, including diagnosis, management, and treatment of the cause of the seizures.

Feline epilepsy types

Feline epilepsy is divided into two types based on the cause of the seizure:

Primary epilepsy is also called idiopathic epilepsy, or epilepsy of unknown origin. In this type of epilepsy, there is no known physical cause of the seizures. When advanced brain imaging was performed, no abnormalities could be found, and even during a post-mortem examination of the cat after death, no structural changes in the brain could be detected. The cause may be genetic, inherited from the cat's parents, although in many cases this does not appear to be the case. Often, the cause of primary epilepsy is unknown. Seizures occur in 30-60% of cats with unknown causes of epilepsy, and approximately 26% of cats under one year of age are diagnosed with epileptic seizures.

Secondary epilepsy is also called acquired epilepsy. In this type, the underlying physical abnormality can be determined through medical history, blood tests, or diagnostic imaging. Examples include extracranial metabolic abnormalities caused by epileptic seizures, which can be identified by blood testing (such as liver disease, kidney disease, and endocrine diseases such as hyperthyroidism) or brain diseases caused by seizures, which can be identified and imaged (including injuries, meningiomas, etc. Oncovascular diseases, infectious and immunological diseases). Secondary epilepsy accounts for about 50% of feline epilepsy cases. Some of these causes are age-related, such as meningiomas and hyperthyroidism being more common in older cats.

Diagnosing the types of epilepsy in cats

Occasionally, the immediate history of an affected cat can point to the cause (for example, a cat from a genetic lineage with a history of epilepsy), but in most cases, detailed investigation is required to make a diagnosis. First, review the cat’s medical history in detail (when did the epilepsy start, etc.) and carefullyAssess clinical symptoms. Investigations can become complex and involve blood tests (such as measuring metabolic enzymes and chemicals such as bile acids to assess liver function, thyroid hormones, etc.), urinalysis, blood pressure measurements, electroencephalography (EEG), cerebrospinal fluid sampling and analysis, ultrasound , X-rays and advanced imaging techniques such as computed tomography (CT) and magnetic resonance imaging (MRI) to check for problems such as brain tumors or signs of head trauma.

Further diagnostic testing in cats may include blood testing for feline leukemia, feline immunodeficiency virus, and serologic testing for potential diseases such as feline infectious peritonitis, cryptococcosis, and toxoplasmosis. In cats with primary epilepsy, no abnormalities will be detected on these tests, and for this reason this type of epilepsy is called a "diagnosis of exclusion."

In secondary epilepsy in cats, a specific underlying cause may be identified after a series of tests and investigations. An accurate diagnosis of the type of epilepsy is crucial when deciding on treatment options.

Treatment of epilepsy in cats

Most seizures last only a few seconds or minutes and do not require immediate treatment other than to protect the cat from physical harm (read our article on seizures in cats). In general, generalized epileptic seizures may last for more than a few minutes (so-called status epilepticus), in which case the animal should be taken to a veterinarian for emergency treatment. Medications such as intravenous anesthetics or diazepam will stop the immediate attack and further medications will be given as needed. For epilepsy that does not stop spontaneously within a few minutes, stopping the seizure is crucial, as failure to do so can lead to brain damage.

In the long term, the goal of treating epileptic seizures in cats is to reduce the frequency of seizures, or to prevent them altogether. The type of treatment depends on the type of epilepsy.

Idiopathic epilepsy: If the specific underlying cause of the epilepsy cannot be determined, the cat is diagnosed with "idiopathic epilepsy" and may require general anti-epileptic drugs to control the seizures. This medication is not always given immediately after a seizure, but is only appropriate if the cat has frequent or group seizures.

Many different anti-epileptic drugs are available. Your veterinarian will be able to advise you on the most appropriate options for your cat. Regular check-ups are important because seizures need to be monitored and anticonvulsant medications can have side effects, meaning medications may need to be adjusted. The most common first-choice anti-epileptic drug is phenobarbital, but in some cases your veterinarian may recommend several alternative medications, including zonisamide, levetiracetam, and clonazepam. Sometimes medications can cause side effects, such as phenobarbital causing thirst, polyuria, polyphagia, sedation, and ataxia.

Other drugs, including potassium bromide, primidone, and phenytoin, have been used in the past but wereFor various reasons, including lack of availability and possible side effects, these drugs are no longer widely used.

Secondary epilepsy: As with the same types of anticonvulsants used to control primary epileptic seizures in cats, cases of secondary epilepsy may require specific treatment depending on the underlying cause. This may mean specific treatment for metabolic conditions (such as liver or kidney problems), or any other therapeutic intervention designed to address the underlying cause (such as surgery for a brain tumor).

Monitoring cats with epilepsy

For any animal with symptoms of epilepsy, it is important for owners to keep a seizure diary, recording the time of seizure, description, and the duration of each seizure. Any recent changes in medications, diet, lifestyle, or other events should be noted. Smartphone apps make this type of record keeping easier, and results should be discussed with your veterinarian every 3 – 12 months, depending on frequency of episodes. If your cat is taking anti-epileptic medications long-term, your veterinarian may recommend periodic blood testing to ensure therapeutic levels are maintained, or to monitor the effects of the medication on your cat's system: this depends on the type of medication given.

Can feline epilepsy be cured?

If the primary cause of secondary epilepsy can be removed (such as an underlying disease, poison, or a brain tumor), the seizures may be permanently cured. If a cat has primary epilepsy, seizures can be controlled with lifelong anticonvulsant therapy, but there are significant individual differences in response to medications and long-term prognosis for effective control.