A seizure is defined as a sudden, controlled electrical disturbance in the brain that can lead to behavioral changes and a change in levels of consciousness. Seizures of any kind are frightening to watch, especially when they happen to our feline friends. In general, seizures themselves are usually not life-threatening unless they are violent or prolonged.
Seizures can occur for many reasons in cats. They can either be intracranial, meaning they’re caused by factors inside the brain, or extracranial, meaning they’re caused by factors outside of the brain.
Most seizures are symptoms of an underlying condition inside or outside the brain. Epilepsy, for example, is a disorder of the brain that causes repeated seizures from an unknown cause when there’s no obvious brain injury.
Unlike the human and canine worlds, epilepsy is a rare condition in cats. That’s why it’s important to investigate all possible causes of seizure activity in cats to appropriately treat them before simply arriving at a diagnosis of epilepsy.
Types of Cat Seizures
Many people who are unfamiliar with seizures probably picture full-body shaking, foaming at the mouth, and loss of consciousness. Although this is common in cats, seizures can also exhibit different symptoms, and not all of them are obvious or violent. From most common to least, the types of seizures in cats include:
Focal Seizures/Partial Motor Seizures: These types of seizures are the most common in cats and only affect a focused part of the brain, leading to localized body effects, depending on which part of the brain is affected. There is usually no loss of consciousness, although the cat may seem dazed. These are usually nonviolent seizures that can be missed by pet parents as the signs are usually subtle—ear flicking and whisker, mouth, and eye twitching.
Generalized Seizures/Grand Mal Seizures: This type of seizure leads to a loss of consciousness and total body function, causing tonic-clonic movements or convulsions. The entire body is affected since a larger area of the brain is often affected. Muscles in the body will move involuntarily and often drastically. Often, cats will clench their mouth, drool, urinate, or defecate during the seizure due to loss of normal body function.
Psychomotor Seizures/Complex Partial Seizures: These types of seizures cause involuntary strange behaviors, including growling, violent chewing at the tail or skin, loud vocalization, or random racing spurts. These are similar to focal/partial motor seizures and are even sometimes considered a specific type of these seizures, as they do not affect consciousness. A well-known example of a psychomotor seizure is a “fly-biting” seizure because a cat will abruptly start chomping their mouth at the air as if trying to catch flies.
The age when seizures start, seizure type, and frequency are considered patterns. Determining the type of seizure pattern can help determine diagnoses and treatments to administer.
Cat Seizure Symptoms
Seizure symptoms can vary greatly depending on the seizure pattern and types.
Grand Mal Seizures
In grand mal seizures, there are often three distinct phases:
Pre-ictal (before the seizure): This phase can start up to a few hours before a seizure occurs. Often, pet parents note a change in behavior, which can be sudden lethargy, dullness, or hyperactivity. Some cats will hide during this phase, while others will seek attention from their family. This time is an “aura” leading up to loss of consciousness that can include brain fog, sleepiness, and confusion.
Ictal (during the seizure): In this phase, the brain loses control over body function and the cat loses awareness. Usually the cat will have full-body convulsions, chewing gum fits (chewing randomly) with drooling or foaming at the mouth, and loss of bowel and bladder control. Most often this phase does not last longer than 30-60 seconds, but it can last longer in some cats.
Post-ictal (after the seizure): This is the time after convulsions stop. It can last from a few hours up to 48 hours while the cat regains full awareness and body function. Pet parents may notice lethargy, dullness, hunger, thirst, vomiting, and often attention-seeking behavior.
Focal and Psychomotor Seizures
Unfortunately, focal seizures and psychomotor seizures do not have a pre- or post-ictal phase. They can come on quickly and seemingly out of nowhere, and cats can recover just as quickly, as if nothing ever happened. Often, the ictal phase of these seizures involves facial twitching, head bobbing, leg paddling (usually just one or two legs are affected), snapping the mouth, meowing, growling, hissing, circling persistently, or random running.
What Causes Seizures in Cats?
There are multiple causes of seizures in cats.
The most common type are grand mal seizures that occur only one time and are caused by toxin ingestion, hypoglycemia (low blood sugar), or loud noise or bright light stimuli.
Toxins that can cause seizures in cats include ethylene glycol (antifreeze), rodenticide (rat poison—specifically neurotoxic types), and medication overdoses such as antihistamines or certain behavior-modification medications.
Permethrin toxicity is often mistaken for seizures, as it can lead to severe muscle twitches. This toxicity is most often caused by inappropriate flea/tick preventative application—either too high a dose or using dog flea or tick medication on a cat. Permethrins are often used in dog preventative products because they are not toxic to dogs at appropriate levels, but even small amounts can be catastrophic in cats. Most cats with this toxicity will not respond to anti-convulsant medication but will respond to muscle relaxers and sedatives.
Hypoglycemia is often seen in kittens that are malnourished, are not eating well, are not being fed appropriate calories, or have a lot of internal parasites. Hypoglycemia is also seen in any age cat that is overdosed on insulin therapy. Ask your vet about low blood sugar and insulin therapy if your cat has just been diagnosed with diabetes mellitus.
Loud Noises and Bright Lights
Loud noises and bright lights are known to cause seizures in cats. We don’t fully understand why high-pitched noises and certain lights can cause these seizures.
Metabolic Diseases and Epilepsy
Multiple seizures can be caused by epilepsy or metabolic disease such as liver disease, kidney disease, or thyroid disease. Recurrent seizures are seen most frequently in cats over the age of 6 due to underlying diseases, though epilepsy is often diagnosed between the ages of 1 and 3.
Epilepsy is either genetic (which is rare in cats) or caused by abnormal brain development, brain trauma, infectious disease, or cancer. Sometimes, no cause is found after a multitude of testing, and in this case, the seizure disorder is called idiopathic epilepsy. This is very uncommon in cats.
Heatstroke and high fevers (from infections, certain cancers, or immune-mediated diseases) can lead to brain malfunction and seizure behavior as well.
Disease of the Brain
Intracranial disease (disease within or around the brain) is a common cause of seizures in cats. Inflammation around the brain (called meningitis or encephalitis) caused by infections such as Cryptococcus, Toxoplasmosis, feline infectious peritonitis, or immune-mediated causes can lead to seizures.
Vascular Issues or Stroke
Vascular events or strokes are possible but less common in cats than dogs. These are often caused by medical conditions such as hyperthyroidism, heart disease, diabetes mellitus, and kidney failure. A secondary effect of these conditions is hypertension, which can lead to vascular events.
Brain tumors are a common cause of seizures in cats older than 10 years old. Often these tumors are benign and slow-growing from the tissue surrounding the brain itself. They can be relatively easy to remove via surgery. As the tumor grows, it puts pressure on the brain tissue, leading to inflammation and seizure activity.
What to Do When a Cat Has a Seizure
If your cat experiences a seizure that lasts longer than 2-3 minutes, or has multiple seizures in a row without returning to normalcy between them, seek emergency care. A condition called status epilepticus can occur, which is a medical emergency. This can lead to severely elevated body temperatures, swelling of the brain, coma, and death if left untreated.
Though seizures are frightening to witness, most are not medical emergencies. If your cat has multiple seizures in a day with a return to normalcy between each one, or if they have more than one seizure monthly but are otherwise acting normally, contact your veterinarian to discuss these signs. Keep a log of dates, times, types, frequency, and duration of seizures and bring this with you to your appointments.
If possible, take a video of the event. This can be very helpful when describing the seizure to your veterinarian. It is important to give as much information about what happened as possible, such as pre-ictal, ictal, and post-ictal symptoms, how long the seizure lasted, how long the pre- and post-ictal phases lasted, and any underlying medical conditions or possible toxin exposure. This history can help with diagnosis of the cause of the seizure.
The thrashing associated with some seizures can harm your kitty, so it’s important to try to help them avoid injury if you note a seizure coming on.
Again, not all seizures have a pre-ictal phase, but those that do can alert you that your cat may be about to have a seizure. In this phase, you can set up padding with thick blankets or pillows to keep your cat from getting injured during a grand mal occurrence. Keep lighting and noise to a minimum to avoid triggering stimuli.
During the ictal phase, always avoid putting anything near your cat’s mouth, especially your face or hands. Their jaw will involuntarily clamp shut, which can cause injury. Just sit with your kitty on the protective blankets and pillows and avoid holding them, as sometimes seizures can cause unexpected aggression.
As the active seizure phase slows, speak slowly, softly, and calmly to your cat. Calmness is necessary, as your cat may be scared or confused upon recovery. Have some water and food available for your cat to try, but only small amounts to avoid belly upset and vomiting after a seizure.
Can a Cat’s Behavior Change After a Seizure?
Your cat may temporarily show signs of aggression during a seizure due to confusion. Most cats do not have long-term effects following a seizure event. Episodes of status epilepticus can cause longstanding effects due to lack of oxygenation to the brain. Seizures caused by brain tumors may also cause a behavior change in your cat secondary to the pressure/inflammation on different parts of the brain itself.
Can a Cat Die From a Seizure?
Deaths from seizures in cats are not common. Most often, fatalities come from untreated status epilepticus, toxin ingestion that causes other metabolic abnormalities, or chronically low blood sugar that leads to a ketotic state, where the body burns fat instead of sugar. Certain infections such as feline infectious peritonitis (FIP), which is often fatal, may also cause seizures, but the deaths are usually not caused by the seizure itself.
How Vets Find the Cause of a Cat’s Seizures
Testing for extracranial causes of seizures is much easier than testing for intracranial causes. The only way to thoroughly image the brain and its surrounding tissues is via MRI, which can be expensive for pet parents. Thus, your veterinarian will start by ruling out extracranial causes first. This testing includes:
Full bloodwork to investigate any bone marrow, kidney, liver, or gastrointestinal diseases
Urine testing to look for signs of infection or kidney disease
Taking your cat’s blood pressure to check for hypertension
Infectious disease testing to rule out viral infections (such as FIP, FIV, feline leukemia), bacterial infections, parasitic infections (Toxoplasmosis), or fungal infections such as Cryptococcus
Abdominal imaging through x-rays or ultrasound to further stage chronic diseases such as kidney disease, liver disease, or cancer
Intracranial disease is often confirmed or ruled out with an MRI. This allows imaging of the brain and the meninges (tissues surrounding the brain). Often, a sample of spinal fluid is obtained to help rule out certain infectious diseases and assess for inflammation.
Treatments for Cats With Seizures
Treatment for seizures in cats varies tremendously depending on the underlying cause. Treating underlying medical conditions such as kidney disease, hypertension, diabetes mellitus, liver disease, and cancers is necessary to avoid any more seizure activity.
Often, no therapy is recommended after first-time seizures. Your veterinarian will usually recommend close monitoring to see if another one occurs, and if so, they will want to know how quickly after the first seizure it happens.
Anti-convulsant medications such as phenobarbital, potassium bromide, levetiracetam (Keppra), or zonisamide are used for frequent seizure activity, no matter the underlying cause. These medications are the mainstay treatments for epilepsy and can be used alone or in combination, as each cat may respond differently.
Often, anti-convulsant therapy is lifelong and monitored closely with blood testing to check for ideal blood levels. Some of the medications, particularly phenobarbital, can have toxic effects at certain levels.
Cats with hypoglycemia, toxin ingestion, or severe systemic illness (such as kidney failure) often require hospitalization, intravenous fluid therapy, sometimes sugar (dextrose) supplementation, and focused therapies for their underlying conditions. Luckily, kittens with hypoglycemic seizure events often recover well with sugar supplementation in a hospital setting with appropriate parasitic control and caloric intake.
Can You Prevent Seizures in Cats?
Preventing further seizures in cats is often not possible once seizure activity starts, even with exceptional veterinary and home care. Frequent monitoring of therapies and metabolic status is usually required throughout a cat’s life. The goal is lowering the seizure duration and frequency as much as possible to allow your kitty a happy, healthy life by your side.
Featured image: iStock.com/cagkansayin
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