A first seizure in a cat who is no longer young is a clue. According to a specialist review of seizures in cats, primary epilepsy (seizures with no cause that tests can find) usually starts between 1 and 7 years of age. When seizures begin after about age 7, an underlying problem is more likely: high blood pressure, kidney or thyroid disease, low blood sugar, a brain tumor or a poison. Many of these can be found, and several can be treated.
If your cat is having a seizure right now, keep your hands clear, make sure they can't fall down stairs or off furniture, and note the time. Go to your vet or an emergency hospital now if the seizure lasts more than 5 minutes, if a second one starts before your cat has recovered, or if several come one after another. If the seizure stopped on its own and your cat is coming around, call your vet the same day. If your cat may have been poisoned, or is diabetic and gets insulin, call your vet or a poison line right away, even if the seizure was short.
Why Older Cats Have Seizures
A seizure is a burst of abnormal electrical activity in the brain. Vets sort the causes into three groups: primary (idiopathic) epilepsy, with no cause tests can find; structural causes inside the brain, such as a tumor or stroke; and reactive seizures, where the brain is normal but something elsewhere, such as failing kidneys or low blood sugar, is not. Reactive seizures usually stop once that problem is corrected.
Age shifts the odds. In the same review, only about 1 in 4 cats with seizures met the criteria for primary epilepsy. In a study of 91 cats seen for seizures at a German veterinary teaching hospital, cats with idiopathic seizures averaged 3.5 years old, while cats with reactive or structural causes averaged about 8 years. So when a senior cat starts having seizures, your vet looks for a cause first. Primary epilepsy is still possible, but it is diagnosed by ruling everything else out: normal bloodwork, blood pressure, MRI and spinal fluid.
Possible cause | What links it to seizures | How the vet looks for it |
|---|---|---|
High blood pressure | Common in older cats, often with kidney or thyroid disease. Can damage the brain and eyes | Blood pressure reading, eye exam |
Kidney disease | In end-stage kidney failure, waste builds up and affects the brain. Also the most common cause of high blood pressure in cats | Bloodwork, urine test, blood pressure |
Overactive thyroid (hyperthyroidism) | Mostly middle-aged and older cats. Severe cases can cause seizures, directly or through high blood pressure | Thyroid hormone (T4) blood test, blood pressure |
Low blood sugar | Usually too much insulin in a diabetic cat; less often an insulin-producing tumor (insulinoma) | Blood glucose |
Liver disease | A failing liver stops clearing substances that affect the brain (hepatic encephalopathy) | Bloodwork, bile acids test |
Brain tumor | Meningioma and lymphoma are the most common types in cats | MRI or CT, usually at a referral hospital |
Stroke or bleeding in the brain | A blocked or burst blood vessel damages part of the brain | MRI |
Brain infection or inflammation | For example FIP or toxoplasmosis | Spinal fluid (CSF) tap, infection tests, MRI |
Poisons | Dog flea products containing permethrin, insecticides, some essential oils | Your history of what your cat touched or ate |
Our guides to why a cat drinks a lot of water, kidney disease in cats and liver disease in cats go deeper on several of these causes.
As for tumors: in a Swiss study of 61 cats with brain tumors, about 1 in 4 had seizures. A tumor is one possibility, not the default answer.
Ask About Blood Pressure
High blood pressure is the cause most worth asking about by name. International feline guidelines call it common in older cats and note that it is measured too rarely. According to Cornell's Feline Health Center, disorientation, loss of balance, seizures and other neurologic signs show up in roughly 15 to 40% of cats with high blood pressure, and they may improve with treatment. Sudden blindness from a detached retina can be the first thing an owner notices. Cats with kidney disease or an overactive thyroid should have their blood pressure checked regularly.
Sound-Triggered Seizures (FARS)
Feline audiogenic reflex seizures (FARS) are set off by high-pitched sounds and belong almost entirely to old age. In the first study of 96 affected cats, seizures started at a median age of 15. The typical sign is a sudden jerk of the body or head (a myoclonic seizure). Half were deaf or hard of hearing, and in most cats it did not get worse over time. If your older cat jerks at certain sharp sounds, film it and tell your vet.
Poisons: Dog Flea Products and Essential Oils
Dog flea and tick products. Permethrin, an insecticide used in many dog spot-on treatments, can be highly toxic to cats, causing muscle twitching and seizures. In an Australian review of 42 poisoned cats, most had a dog product put directly on them, and a few lived with a dog that had just been treated. Signs usually start within a few hours but can take up to 2 to 3 days. Use only flea products labeled for cats, and ask your vet before treating a dog who lives with a cat.
Tea tree oil and other essential oils. Never put tea tree oil or any concentrated essential oil on your cat. The Merck Veterinary Manual explains that cats are more sensitive than dogs because they are short on a liver enzyme that clears some of these compounds, and grooming means oil on the fur gets swallowed. In an ASPCA Animal Poison Control review of 443 dogs and cats exposed to undiluted tea tree oil, most owners had used it on purpose, and signs such as drooling, weakness, wobbliness and tremors started within 2 to 12 hours. Merck lists eucalyptus, wintergreen and pennyroyal among the oils that can cause seizures, and diffusers can leave droplets on fur.
If your cat may have been exposed to either, call your vet or an animal poison line now: ASPCA Animal Poison Control at (888) 426-4435 or Pet Poison Helpline at (855) 764-7661. Both are open 24/7, and a fee may apply. If you also have a dog, our guide to toxins that can cause seizures in dogs covers household poisons, including the permethrin risk to cats.
What a Seizure Looks Like in a Cat
Cats don't always have the dramatic, all-four-legs seizure people picture. They are more likely than dogs to have focal seizures, which start in one part of the brain, and about half of the cats in the 91-cat study had this kind.
Generalized seizures
The whole brain is involved. International Cat Care lists sudden collapse, loss of awareness, violent shaking or paddling of all four legs, chewing or twitching of the face, drooling, and passing urine or stool. These usually last 1 to 3 minutes.
Focal seizures
Only part of the brain is involved, so they are easier to miss. Watch for:
- drooling, lip smacking, chewing motions or repeated swallowing
- twitching of the eyelids or face
- dilated pupils and staring into space
- crying out or growling
- odd movements of the head, neck or one leg
- sudden biting, licking or frantic running
A focal seizure can spread into a generalized one.
Before and after
Some cats act differently for hours or even days before a seizure: restless, clingy or hiding. Just before it, you may see drooling, growling or pacing.
Afterward comes the recovery (postictal) phase. Your cat may be wobbly, confused and briefly blind for a few seconds to a few hours, and subtle changes can take a few days to fade. Don't count this recovery when you time the seizure.
This owner's video shows what a seizure can look like at home:
Fainting from a heart problem can look like a seizure (about 3% of cats in the 91-cat study), and a video helps your vet tell them apart.
What to Do During a Seizure
- Stay calm. Most seizures stop on their own within 1 to 3 minutes.
- Note the time it starts. Seconds feel like minutes when you're watching.
- Keep them away from stairs and edges. Move your cat only if they're in danger, such as at the top of the stairs or the edge of a couch.
- Keep your hands away from their mouth. A seizing cat isn't aware of you and can bite or scratch without meaning to. Don't hold them down.
- Film it if you can do so safely.
- Note when it stops. Then let your cat recover somewhere quiet, with other pets kept away, and call your vet.
When Is a Cat Seizure an Emergency?
Go to your vet or an emergency hospital now if:
- the seizure lasts more than 5 minutes
- a second seizure starts before your cat has recovered from the first
- your cat has several seizures one after another
A seizure over 5 minutes, or seizures without recovery in between, is called status epilepticus. The ACVIM consensus on emergency seizure care uses 5 minutes as its threshold because prolonged seizures can damage the brain, and clusters can turn into status epilepticus.
Call your vet or a poison line right away, even if the seizure was short, if:
- your cat may have touched or swallowed a poison, such as a dog flea product or an essential oil
- your cat is diabetic and gets insulin (seizures can mean dangerously low blood sugar, and the Merck Veterinary Manual says to call your vet immediately)
Call your vet the same day if:
- your cat had a seizure that stopped on its own, even a short one, and is recovering
- your cat already has a seizure diagnosis and has a seizure that's different: longer, closer together, or a new kind
If your cat has epilepsy, your vet may give you an emergency plan; follow it exactly.
For the drive, wrap your cat loosely in a towel or blanket and put them in a carrier.
What Your Vet Will Check
After your history and video, the workup may include:
- a full physical and neurologic exam, including a look at the back of the eyes, where high blood pressure can leave early signs
- a blood pressure reading, which the specialist review above recommends for every cat with new seizures, whatever the other results show
- bloodwork and a urine test, including thyroid level and blood sugar
- a bile acids test if liver disease is possible
- an MRI of the brain and a spinal fluid (CSF) tap if the first tests are normal, usually at a referral or specialty hospital
Between seizures, some cats show other signs of a brain problem, such as walking in circles, new blindness, or being wobbly, restless or sleepy. If you've seen your cat pressing their head against a wall, mention it; our guide to head pressing in cats and dogs explains what it can mean.
Bring or write down:
- the date, time and length of each seizure, and any video
- whether the seizures are getting more frequent or longer
- other health problems, and every medicine or supplement your cat takes, including insulin
- any flea or tick product used on any pet in the home, and any essential oils or diffusers
Treatment and Living With a Cat Who Has Seizures
Treatment depends on the cause. Reactive seizures usually stop once the problem behind them is under control. A brain tumor or inflammation needs its own plan, and your vet may refer you to a neurologist or oncologist.
If seizures keep coming back, your vet may start long-term anti-seizure medicine, usually after repeated seizures, a cluster, or a seizure that wouldn't stop. Phenobarbital and levetiracetam are two options vets commonly choose for cats; your vet picks the medicine and the dose and checks bloodwork along the way. Some seizure medicines used in dogs are not recommended for cats, so never give your cat a dog's seizure medicine.
If your cat is on seizure medicine:
- Give it exactly as prescribed. Don't change the amount or timing without talking to your vet.
- Never stop it suddenly. Seizures can come back, sometimes worse.
- Order refills a few days before you run out.
- Ask which side effects to expect. Sleepiness and wobbliness are common early on. Call your vet if your cat stops eating or seems very unwell.
- Check before adding anything else, including supplements, herbal products and essential oils.
Medicine reduces seizures but may not stop every one. A seizure diary (date, time, length, what it looked like) plus the occasional video helps your vet adjust the plan.
At home, check that window screens are secure so your cat can't fall out, since a head injury can itself cause seizures. With the cause treated or the seizures controlled, many cats with epilepsy go on to live long, happy lives.
Originally written by Helen Roberts. Updated by the I Love Veterinary editorial team.
Sources
- Moore SA: Seizures and epilepsy in cats (Veterinary Medicine: Research and Reports, 2014)
- Schriefl S and colleagues: Etiologic classification of seizures in cats, 91 cases (JAVMA, 2008)
- Tomek A and colleagues: Intracranial neoplasia in 61 cats (Journal of Feline Medicine and Surgery, 2006)
- Lowrie M and colleagues: Audiogenic reflex seizures in cats (Journal of Feline Medicine and Surgery, 2016)
- ACVIM Consensus Statement on the management of status epilepticus and cluster seizures in dogs and cats (2024)
- ACVIM Consensus Statement on systemic hypertension in dogs and cats (2018)
- ISFM Consensus Guidelines on the Diagnosis and Management of Hypertension in Cats (2017)
- Cornell Feline Health Center: Hypertension
- Cornell Feline Health Center: Hyperthyroidism in Cats
- Merck Veterinary Manual: Epilepsy in Small Animals
- Merck Veterinary Manual: Disorders of the Pancreas in Cats
- Merck Veterinary Manual: Toxicoses From Essential Oils in Animals
- Merck Veterinary Manual: Ectoparasiticides Used in Small Animals
- Boland LA, Angles JM: Feline permethrin toxicity, 42 cases (Journal of Feline Medicine and Surgery, 2010)
- Khan SA and colleagues: Concentrated tea tree oil toxicosis in dogs and cats, 443 cases (JAVMA, 2014)
- Pet Poison Helpline: Tea Tree Oil
- International Cat Care: Seizures in cats
- ASPCA Pet Health Insurance: Cat Epilepsy (Dr. Wendy Hauser)
- ASPCA Animal Poison Control Center
- Pet Poison Helpline
This article is for general information and is not a substitute for advice from your veterinarian.
