Cat - Seizures

Seizures and epilepsy are less commonly encountered in cats than dogs. They are, however, the most common sign of disease affecting the front part of the brain in the cat.

Some important terms:

Seizure (convulsion, ictus, fit) - an involuntary disturbance of normal brain control which is usually seen as uncontrollable muscle activity. Seizures can be single and very occasional or may occur in clusters followed by long periods (weeks to months) without fitting.

Epilepsy - describes recurrent seizures.

Preictal (aura) - the change in character that may occur prior to a fit e.g. nervousness, attention seeking, head turning.

Postictal - following a seizure it can take 24-48 hours for a cat to return to normal. This period is called the postictal phase and is characterised by a variety of signs including sleepiness, pacing, depression, excitement, excessive eating and drinking.

Generalised seizures (= a grand mal seizure) Jerking movements, rigid limbs, paddling/running movements, loss of faecal and urinary control. The head is often bent backwards along the spine.

Status epilepticus - describes continuous fitting for more than 5-10 minutes or repeated seizures without full recovery in between. Cats in status require immediate treatment.

Partial seizures- less commonly recognised when only certain muscle groups are involved, or may be characterised by behavioural changes (e.g. tail chasing, biting at imaginary objects, aggression).

Seizures often occur at times of changing brain activity e.g. during phases of sleep, excitement or feeding. Affected cats can appear completely normal in between fits. Many different diseases can lead to seizures, either diseases outside of the brain such as some liver diseases, low blood glucose or calcium levels, or ingestion of particular toxins, or diseases within the brain such as an infection, tumour, trauma or developmental abnormality. It is therefore important that diagnostic tests are performed to try to discover the cause of the fitting as treatment of the underlying disease is most likely to lead to successful control of the seizures. Idiopathic epilepsy is the term used to describe when no underlying cause for the seizures is identified.

How can I help my veterinary surgeon to make a diagnosis ?

Carefully observing (and, if possible, filming) your cat particularly at the beginning of a fit can provided very valuable information to your veterinary surgeon about the types of disease that may be causing the problem.

1. Age at which fits began, are they getting worse
2. Chronicity - i.e. are the seizures intermittent or did they develop suddenly
3. Frequency, multiplicity of seizures
4. Association of seizures i.e. asleep, excitement, feeding
5. Other signs of ill health e.g. poor appetite, excessive drinking, reduced exercise
6. Information about your cat's lifestyle may also be important
7. Medication use - especially recent worming or use of flea control products
8. Diet
9. Access to poisons

Both diseases which involve the brain directly (intracranial) and conditions which affect other body systems (extracranial) can cause fitting. With recent developments in treatment many diseases which have previously been untreatable may now be treated though this can require referral to a specialist centre.

How can a diagnosis of the cause of the seizures made?

A range of tests are often needed before a final diagnosis can be made, initially this is likely to involve blood samples to look for extracranial causes of the fitting. Following this a general anaesthetic may be required to allow radiographs (x-rays) of the skull to be taken and the fluid that surrounds the brain (cerebrospinal fluid) sampled. In order to actually look at the brain, powerful imaging techniques are required e.g. magnetic resonance imaging (MRI) and computer assisted tomography (CT), these tests are only available at a limited number of specialist centres.

What treatments are available?

It is important that a cat which has had more than one seizure receives treatment even if the cause is not as yet clear as each fit can lead to further brain damage increasing the likelihood of more fits in the future. Treatment of the underlying causes of fits is not within the scope of this leaflet. In some cases where the cause of the fitting is not known or is untreatable then the seizures need to be treated directly. A variety of treatments are available, the treatment chosen will depend on each individual case. Several changes of dose rate, timing and drug may be required before the regime that suits your cat best is found. This can be a frustrating time but the benefits of finding the right treatment become self evident. Even with treatment it may not be possible to completely prevent fitting, in many cases the aim is to reduce the seizures so your cat can lead a more or less normal life.

Golden rules of treatment

• ALWAYS follow the instructions on the label both the dose rate and timing of the medication is important to maintain adequate drug levels in the bloodstream.
• NEVER run out of the medication as sudden withdrawal of treatment can lead to serious fitting.
• LET your vet know when your supply is running low so a repeat prescription can be arranged. This is particularly important if the treatment needs to be ordered specially for your cat.
• KEEP these drugs safe as they can be powerful sedatives.
• BE CAREFUL about other drugs including herbal remedies that you also give your cat. If in doubt check with the veterinary practice.

What are the side effects of treatment?

Mild side effects are common particularly at the beginning of treatment or following changes in the regime. The most common side effect is sedation or drowsiness but other signs can also occur, most disappear quite rapidly as the cat becomes used to the medication. If side effects persist or seem severe then the veterinary practice should be informed.

DO NOT BE TEMPTED TO CHANGE THE DOSE OR TIMING OF MEDICATION WITHOUT CONSULTING YOUR VETERINARY SURGEON FIRST

Why has treatment failed?

Sometimes treatment will appear to have failed, in many cases this is because the dosage and timing of the medication is not yet right. Please check that you are following the instructions on the medication label correctly. In some cases your veterinary surgeon may want to take a blood sample to ensure that your cat has adequate circulating blood levels of the medication.

Other causes of treatment failure include:

1. Failure to recognise and treat an underlying disease.
2. Progression of disease.
3. Some cases are uncontrollable even with medication.

Seizures are dramatic and worrying sign to see in your cat. This does not necessarily mean however that nothing can be done for your cat, with the correct treatment, the quality of your cat's life can be dramatically improved.