Seizures are one of the scariest things pet owners may have to face. We often focus our education of seizures on dog owners, especially those with particular breeds. But can cats have seizures too? If so, what should you do if your cat has a seizure? And what can we do as vets?
What is a Seizure?
A seizure is a temporary state of excitation in the brain that results in abnormal electrical activity. The brain is made up of cells called neurones. These are like telephone wires that connect every part of the brain and allow it to send messages around the body.
Neurones are stimulated by electrical activity to carry messages and cause an effect, such as moving muscles. Normally, there is a balance in the brain between excitation and inhibition; some neurones will be active and some will be inactive. This means the brain can coordinate itself and does not get overloaded. However, if there is a seizure, a lot more of the brain is excited and millions more neurones are firing; the brain and body cannot cope with all these signals, causing symptoms of seizures.
Seizures can be caused by problems outside the brain (extracranial), such as toxicities, electrolyte abnormalities, a lack of oxygen or hyperthermia. Alternatively, a seizure can be caused by problems within the brain (intracranial). Caused by damage, infection or blood clots in the brain. Any animal of any age can have a seizure.
Seizures often present as body-wide convulsions (though this is variable, as we will see later), as all the muscles are being told to move by the overexcited neurones. Other common signs include behavioural changes, salivation, urination, defaecation and loss of consciousness. If untreated, seizures can lead to heat stroke, heart and other organ damage, trauma and even death.
Epilepsy
This is a group of neurological disorders that cause periodic seizures. Recurrent brain dysfunction leads to repeated over-excitation of the brain and epileptic seizures. Epilepsy can be caused by a physical problem or an unknown functional problem within the brain. We generally say that any animal that has two or more seizures within a short period of time (variable) has epilepsy.
Can Cats Have Seizures?
Like all animals, cats can indeed have seizures. However, there are a number of key differences between dog seizures (the animal we most commonly see seizuring in practice) and cats.
Seizures in cats are much rarer than dogs, but they aren’t impossible. Some studies say up to 2% of the feline population have seizures. Seizures are common in very young and very old dogs, whereas in cats most seizures are seen in older animals; younger cats can have seizures, but it is much less common. This is because many of the causes of seizures in cats are related to old age.
Cats also tend to have different symptoms compared to dogs. Dogs tend to have generalised seizures where most of their brain is seizuring – these are the ‘classic’ seizures where the whole body convulses. Cats are more likely to have focal or partial seizures. This is where only one part of the brain has seizure activity. As a result, the signs can be a lot more subtle.
Symptoms in cats with partial seizures include salivation, licking, aggression, excessive swallowing, facial twitching, vocalisation, hiding and other unusual behaviour. Cats can still have generalised seizures as described above, or partial seizures can progress to generalised. Severe seizure activity can occur multiple times within short periods (cluster seizures), or can last for many minutes (status epilepticus) – both are emergencies.
Causes of Seizures in Cats
Most cat seizures are caused by intracranial disease.
Cancers
One of the most common intracranial diseases in older cats is sadly cancer – older cats can develop cancer within the brain that grows and compresses the healthy brain around it. This leads to dysfunction and seizure activity. The most common seizure-causing cancers in cats are meningioma, lymphoma and glioma. These cancers often cause other symptoms as well, such as progressive neurological issues, weight loss, behavioural changes and changes in toileting. Treatment is difficult and prognosis varies.
Strokes
Vascular (blood vessel) disease is another common cause of seizures in cats. High blood pressure is a common finding in older cats, often related to heart disease, kidney disease, hyperthyroidism, diabetes and more. The high blood pressure leads to increased pressure around the brain that can cause neurological dysfunction and seizures. Seizures can also be caused by a lack of oxygen reaching the brain – we aren’t sure why this happens in cats, though it could be related to blood clots, low blood pressure, or if you are in the USA, certain types of parasite.
Metabolic disease
Metabolic abnormalities secondary to other diseases are quite common in older cats. Older cats often have disease of the liver or kidneys – these organs are responsible for filtering out toxins from the body. If they aren’t working, these toxic products can reach the brain and cause seizures. We term these diseases hepatic encephalopathy and renal encephalopathy respectively. Hyperthyroidism (overactive thyroid) can also lead to seizures, as it increases the brain’s oxygen and glucose demand – if the body cannot deliver these, the brain starves and can seizure. Other causes of hypoglycaemia (low blood glucose) cause seizures in a similar way.
“True” Epilepsy
Idiopathic epilepsy (this is epilepsy without an obvious cause) was once thought to be rare in cats, especially compared to dogs. However, recent studies have shown that it is more common than we thought. Many of these cats were actually younger, between age 1 and 7. If your cat has regular seizures and is younger, idiopathic epilepsy may be more likely.
Poisoning
As with dogs, a number of toxic substances can cause seizures as well. Toxins affect cats of any age, though outdoor cats may be more likely to eat something they shouldn’t. Common toxins include lead, rat poison, permethrin flea products, fertilisers and more.
Infections
Finally, certain infectious agents can cause seizures in cats of all ages. There is a nasty disease in cats called feline infectious peritonitis (FIP), caused by a virus. It mostly causes fluid build-up in the lungs and abdomen, but it can also cause lesions in the brain that cause seizures. Toxoplasmosis is another disease, caused by a parasite, which can lead to seizures – toxoplasmosis rarely invades the brain and mainly causes gastrointestinal issues. Finally, a fungus called Cryptococcus that can reside in a cat’s nose sometimes invades through the brain in severe cases, causing seizures (although this is fairly uncommon, and the fungus is rare in the UK).
What to Do If Your Cat Has a Seizure
Although seizures are not a normal event, some animals have one seizure in their life, and never show seizure activity again. It is entirely possible that if your cat has a seizure and is fine afterwards, you don’t need to worry. However, it is always a good idea to mention this to your vet as soon as you can. They will probably recommend keeping an eye on them and watching out for further seizure activity. If your cat has more than one seizure within 6 months, further investigation is usually recommended.
If your cat has a seizure, there are a number of steps you should take.
Firstly, check the time. It is important to know how long the seizure lasts, especially if it is a long “status epilepticus” seizure. A seizure is caused by increased activity within the brain, so it is helpful to reduce stimulation as much as possible. Turn off lights, reduce excess noise, act calm and give your cat space.
In fact, it is a good idea to avoid touching your cat as much as you can. Cats in seizures can be aggressive, or you can hurt them accidentally. If you have to move them (such as to the vets), wrap them in a towel and keep them secure.
If your cat has had a seizure before, has a seizure lasting more than 5 minutes, or the seizure is severe, please contact your vet and ask for emergency care – they may ask you to bring your cat in straight away. Even if your cat stops seizuring in the car, continue to your vets so they can check they are okay.
Emergency care for seizures at the vets include drugs to reduce brain activity, cooling your cat, fluid therapy, oxygen, monitoring of blood parameters, and nursing care. It is critical that vets try and stop the seizure activity as soon as possible, and then manage post-seizure complications. This treatment may require your cat staying at the vets for a while. Be aware that the outcome is not always positive for severe seizures.
How We Diagnose Seizures
Investigating why your cat has seizures can be tricky as there are many potential causes. We generally start by asking about your cat’s history – we will want to know the history of their seizure activity, any behavioural changes, your cat’s travel and vaccination history, if they have had any access to toxins, their diet, and so on.
Clinical examination of your cat can help rule out obvious causes of seizures. This may involve a neurological exam, blood testing to rule out metabolic causes, sampling cerebrospinal fluid to look for signs of lesions, or imaging such as ultrasound, x-rays, CT or MRI. If we suspect your cat has diseases that could cause seizures, such as liver or kidney disease, we may do urine or faecal tests, or take biopsies of these organs. Idiopathic epilepsy is trickier to diagnose, as there are few physical changes; diagnosis is usually only possible once we have ruled out all other causes.
Preventing future seizures will depend on the specific cause.
Most age-related diseases in cats are managed with their own specific treatment plans – successful treatment should prevent seizure activity. Cancers causing seizures may be able to be removed surgically or with chemotherapy. There are also a number of drugs available that prevent seizures; phenobarbital is the cheapest and most common, although less well tolerated by cats than dogs; but other options include imepitoin, levetiracetam and gabapentin.
It can initially be difficult calculating the ideal dose for individual cats, so treatment often starts with some trial and error. Most drugs will need to be given orally at least once a day, which requires a lot of input from you. Furthermore, the drugs do have a lot of side-effects that need to be managed. All of this information will be given to you by your vet, if they feel your cat needs long-term anti-seizure medication.
Final Thoughts
Seizures can definitely occur in cats, and although they are uncommon, you now know what causes them, how you can identify and manage a seizuring cat, and how vets will diagnose and treat them. The most important thing for you as an owner to do is to be on the lookout for unusual activity that could indicate your cat is seizuring – most of these strange signs will be innocent, but it is good to identify them just in case. Don’t be afraid of seizures – be prepared so you know the best way to help your cat.
Read more…
Moore, S (2014) “Seizures and Epilepsy in Cats”, Veterinary medicine: Research and Reports Vol 5
International Cat Care – Seizures in Cats
Purina – seizures in older cats
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