What Causes Seizures in Cats: A 2026 Vet Guide

Seizures in cats are caused by abnormal, uncontrolled electrical discharges in the brain’s cerebral cortex, and the underlying reason for those discharges spans a wide range of conditions, from structural brain disease and infectious illness to metabolic disorders and toxic exposures. Understanding what causes seizures in cats matters enormously because the cause determines the urgency, the diagnostic approach, and the entire treatment direction: a brain tumor requires different management than low blood sugar, and a permethrin-poisoned cat needs an entirely different emergency response than a cat with idiopathic epilepsy.

According to the Journal of Veterinary Internal Medicine, intracranial structural disease, particularly meningioma and other central nervous system tumors, accounts for a high proportion of new-onset seizures in cats over 7 years of age, while younger cats are more likely to experience idiopathic epilepsy or congenital vascular abnormalities. The American Veterinary Medical Association recognizes that seizure disorders in cats are a neurological emergency when they persist beyond 5 minutes or recur within a 24-hour window.

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This article covers every clinically recognized cause of cat seizures, the physiological mechanism behind each one, the observable signs you should track before your veterinary appointment, the age and breed-related patterns that shape diagnosis, and the specific emergency thresholds that require immediate care, not a wait-and-see approach.

What Causes Seizures in Cats

Seizures in cats occur when neurons in the cerebral cortex fire in an abnormal, synchronized, and uncontrolled pattern, overwhelming the brain’s normal regulatory circuits and producing the involuntary motor, sensory, and behavioral changes cat owners observe. This abnormal firing can be triggered by disease originating inside the brain itself (called intracranial causes) or by conditions originating elsewhere in the body that disrupt normal brain chemistry (called extracranial or reactive causes).

The cause profile in cats differs from both dogs and humans in important ways. Cats over 7 years of age presenting with new-onset seizures have a much higher probability of structural intracranial disease than same-age dogs. Younger cats under 4 years are more likely to have idiopathic epilepsy or congenital abnormalities such as portosystemic shunts, which redirect blood around the liver and allow neurotoxic substances to reach the brain.

Common broad categories of seizure causes in cats include:

• Intracranial structural disease: brain tumors, inflammatory brain disease, traumatic brain injury
• Metabolic and systemic disease: hepatic encephalopathy, uremic encephalopathy, hypoglycemia, hypertensive encephalopathy from hyperthyroidism or renal disease
• Toxin exposure: permethrin, organophosphates, ethylene glycol, certain plants and human medications
• Infectious disease: feline infectious peritonitis (FIP), toxoplasmosis, cryptococcal meningitis, FIV-associated encephalitis
• Idiopathic (unknown cause): diagnosed by exclusion after all other causes are ruled out

Outdoor cats face substantially higher toxin and infectious disease exposure risk than exclusively indoor cats, a factor that shapes the diagnostic priority list a veterinarian works through from the first appointment.

How the Feline Brain Produces Seizures

A cat seizure begins at the cellular level when the balance between excitatory and inhibitory neurotransmission in the cerebral cortex breaks down. Normally, gamma-aminobutyric acid (GABA), the brain’s primary inhibitory neurotransmitter, prevents neurons from firing in a runaway cascade. When GABA-mediated inhibition fails, excitatory glutamate-driven signaling dominates, voltage-gated sodium channels open across large populations of neurons simultaneously, and a wave of uncontrolled synchronous depolarization spreads through the cortex.

Think of it like a stadium full of people who are all supposed to be talking to their immediate neighbor, with a referee keeping everyone’s volume in check. When the referee (GABA inhibition) disappears, the crowd noise builds from one corner until the entire stadium is in simultaneous uproar. That uproar in neural terms is the ictal event a cat owner sees as shaking, paddling, and loss of consciousness.

Different causes disrupt this balance through different mechanisms. Structural lesions like tumors or areas of inflammation physically compress or destroy GABAergic interneurons, permanently reducing inhibitory capacity. Metabolic causes work differently: in hepatic encephalopathy, excess blood ammonia crosses the blood-brain barrier and is converted to glutamine in astrocytes via the enzyme glutamine synthetase. The resulting astrocyte swelling impairs normal synaptic function and shifts the excitatory-inhibitory balance toward uncontrolled firing.

Cats with hypoglycemia (abnormally low blood glucose) experience a third mechanism: their neurons run out of the ATP they need to maintain the sodium-potassium ATPase pumps that keep resting membrane potential stable. When those pumps fail, neurons depolarize spontaneously and trigger seizure activity.

Individual variation note: intact male cats may have slightly higher exposure risk for infectious encephalitides due to territorial outdoor roaming behavior, increasing their probability of toxin and pathogen contact compared to indoor spayed females.

Types of Seizures in Cats

Veterinarians classify seizures in cats into two primary categories based on how much of the brain is involved: generalized seizures and focal seizures, with the distinction having direct clinical significance for identifying the underlying cause.

Generalized seizures involve both hemispheres of the cerebral cortex simultaneously from the outset. They produce the classic picture most cat owners recognize: sudden bilateral muscle rigidity (the tonic phase), followed by rhythmic involuntary jerking of all four limbs (the clonic phase), accompanied by loss of consciousness, excessive salivation, and loss of bowel or bladder control. Generalized seizures are more commonly associated with metabolic and toxic causes, though structural and idiopathic causes can also produce them.

Focal seizures, also called partial seizures, originate in a discrete area of the cortex. They may produce twitching of a single limb, repetitive facial movements such as jaw chomping or whisker twitching, unusual repetitive behaviors, or sudden unexplained vocalization without full-body involvement. Focal seizures are more frequently associated with structural brain lesions (tumors, inflammatory foci) on the side of the brain where the focal discharge originates, according to clinical guidance published in Veterinary Clinics of North America: Small Animal Practice.

Senior cats (over 8 years) presenting with new-onset focal seizures warrant MRI as a priority diagnostic step given the high prevalence of meningioma in this age group.

Intracranial Causes of Seizures in Cats

Intracranial causes are those originating within the brain itself, and they account for a substantial proportion of feline seizure cases, particularly in middle-aged to older cats. The Merck Veterinary Manual identifies intracranial structural disease as one of the leading cause categories in cats over 7 years presenting for first seizure evaluation.

Meningioma is the single most common primary brain tumor in cats. It arises from the meninges, the three-layered membrane system (dura mater, arachnoid mater, and pia mater) that surrounds the brain and spinal cord. As the tumor grows, it exerts mechanical pressure on adjacent cortical tissue, disrupts local blood supply, compresses GABAergic inhibitory interneurons, and generates focal areas of abnormal electrical activity that escalate into seizures.

Unlike in humans where meningiomas can be slow-growing and sometimes managed conservatively, feline meningiomas often grow rapidly enough to produce clinical signs within weeks to months. Other intracranial structural causes include:

• Gliomas: tumors arising from glial cells (astrocytes, oligodendrocytes) within the brain parenchyma itself, less common than meningiomas in cats but more invasive
• Traumatic brain injury: blunt-force head trauma (from falls, vehicle accidents) causing cortical contusion, hemorrhage, or cerebral edema that disrupts normal neuronal firing
• Inflammatory brain disease: immune-mediated encephalitis or granulomatous meningoencephalitis, in which the immune system attacks the brain tissue, producing focal areas of destruction and reactive seizure activity
• Intracranial hemorrhage: bleeding into the brain parenchyma or subarachnoid space, from hypertensive crisis, coagulopathy, or vascular malformation

The brain is a high-demand organ with no energy reserves to spare. A tumor the size of a marble pressing against the motor cortex creates enough local disruption to trigger repeated seizure events even without destroying large volumes of tissue. This is why some cats with early meningiomas present with seizures before other behavioral or neurological signs become obvious.

Cats in this cause category: more common in cats over 7 years, not strongly linked to any specific breed, but domestic longhair and domestic shorthair cats are most frequently represented in published case series simply by population size.

Extracranial and Metabolic Causes of Cat Seizures

Extracranial causes of cat seizures are conditions originating outside the brain that disrupt normal neuronal function by altering the chemical environment the brain depends on. These are sometimes called reactive seizures because the brain is reacting to an abnormal systemic state rather than harboring intrinsic disease.

Hepatic encephalopathy is one of the most clinically recognized extracranial causes in cats. It occurs when the liver fails to detoxify ammonia produced during protein metabolism, allowing blood ammonia to accumulate. In the brain, excess ammonia is converted to glutamine inside astrocytes, causing those cells to swell and disrupting normal synaptic communication. This astrocyte dysfunction shifts the excitatory-inhibitory balance and produces seizures. Portosystemic shunts, a congenital abnormality in which blood bypasses the liver via abnormal vascular connections, are a leading cause of hepatic encephalopathy-associated seizures in young cats, often diagnosed under 2 years of age.

Hypoglycemia (abnormally low blood glucose) deprives neurons of their primary energy substrate. When blood glucose drops below approximately 40 to 50 milligrams per deciliter, neuronal ATP production becomes inadequate to maintain sodium-potassium ATPase pump function, membrane potential destabilizes, and uncontrolled depolarization follows. Hypoglycemia-related seizures in cats are seen with insulin-secreting pancreatic tumors (insulinomas), severe hepatic disease, starvation, and rarely with insulin overdose in diabetic cats receiving treatment.

Other metabolic causes include:

• Uremic encephalopathy: severe chronic kidney disease allows uremic toxins to accumulate in the blood. Guanidino compounds and other uremic toxins cross the blood-brain barrier and interfere with GABA-A receptor function, lowering the seizure threshold.
• Hypertensive encephalopathy: severe systemic hypertension (typically systolic blood pressure above 180 to 200 mmHg) overwhelms the brain’s cerebrovascular autoregulation, forcing open normally protected cerebral arterioles and allowing plasma to leak across the blood-brain barrier, producing focal cerebral edema and seizure activity. Research published in the Journal of Feline Medicine and Surgery has found systemic hypertension to be one of the most frequently identified metabolic contributors to feline seizures in geriatric cats.
• Electrolyte disturbances: severe hyponatremia (low blood sodium) and severe hypocalcemia (low blood calcium) both lower neuronal membrane excitability threshold and can precipitate seizures.
• Polycythemia: abnormally high red blood cell concentration increases blood viscosity, reduces cerebral microcirculatory flow, and creates focal areas of relative ischemia in cortical tissue, producing seizure activity.

Key Takeaway: The same observable seizure in a cat can originate from a brain tumor, a liver shunt, severe kidney disease, or dangerously high blood pressure. The cause cannot be determined from watching the seizure; it requires veterinary blood testing and diagnostic imaging.

Toxins That Cause Seizures in Cats

Cats are particularly vulnerable to toxin-induced seizures because of a species-specific metabolic limitation: the feline liver has significantly reduced glucuronidation capacity compared to dogs and humans. Glucuronidation is a phase II hepatic detoxification pathway in which the liver attaches glucuronic acid to lipid-soluble compounds, making them water-soluble and excretory. Because cats cannot process many toxins through this route efficiently, substances that cause no harm to dogs can produce severe, life-threatening neurological toxicity in cats at much lower doses.

Permethrin is the most clinically significant toxin associated with feline seizures. It is a synthetic pyrethroid insecticide commonly used in dog-labeled flea prevention products. When applied to cats (or when cats groom dogs recently treated with permethrin-containing products), it causes prolonged opening of voltage-gated sodium channels in neuronal membranes, producing repetitive and uncontrolled action potentials. Clinical signs include whole-body tremors, hypersalivation, severe muscle fasciculations, and tonic-clonic seizures. According to the ASPCA Animal Poison Control Center, permethrin toxicity is one of the most common calls received regarding feline toxicological emergencies.

If permethrin exposure is suspected, call the ASPCA Animal Poison Control Center at 888-426-4435 immediately and take your cat to an emergency veterinary clinic without delay.

Additional toxins that cause seizures in cats:

• Organophosphate and carbamate insecticides: inhibit acetylcholinesterase, causing excess acetylcholine accumulation at nerve junctions, overstimulation of muscarinic and nicotinic receptors, and eventual seizure activity
• Ethylene glycol (antifreeze): rapidly metabolized to oxalic acid and glycolic acid, which cause severe acute kidney injury and metabolic acidosis leading to uremic encephalopathy and seizures; cats are more sensitive to lower doses than dogs
• Toxic plants: lilies (Lilium and Hemerocallis species) cause acute renal failure in cats, with secondary uremic encephalopathy and seizures; other plants including sago palm, autumn crocus, and yew produce hepatic or direct neurological toxicity
• Human medications: NSAIDs (particularly ibuprofen), antidepressants (especially selective serotonin reuptake inhibitors and tricyclics), benzodiazepines at high doses in cats not tolerant to the drug, and muscle relaxants can all produce CNS toxicity and seizures when accidentally ingested
• Caffeine and xylitol: caffeine blocks adenosine receptors and stimulates the CNS; xylitol causes profound hypoglycemia through insulin release in dogs (effect in cats is less documented but CNS toxicity has been reported)

Outdoor cats and cats in households with unsecured cleaning products, medications, or garden pesticides carry substantially higher toxin exposure risk than indoor-only cats.

Feline Idiopathic Epilepsy

Feline idiopathic epilepsy is a diagnosis of exclusion, meaning it is only confirmed after a thorough workup has ruled out all identifiable intracranial and extracranial causes of seizure activity. In idiopathic epilepsy, the brain produces recurrent seizures without any detectable structural lesion, metabolic abnormality, toxic exposure, or infectious disease. The suspected underlying mechanism involves a genetically determined imbalance in the excitatory-to-inhibitory neurotransmitter ratio within the cerebral cortex.

Idiopathic epilepsy is less common in cats than in dogs. A clinical review published in the Journal of Veterinary Internal Medicine found that idiopathic epilepsy accounts for approximately 22 to 25 percent of feline seizure cases in specialist referral populations, with the majority of remaining cases attributable to structural or metabolic causes. This is a different pattern from dogs, in which idiopathic epilepsy is considerably more prevalent.

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The typical profile of a cat with feline idiopathic epilepsy:

• Age of onset: most commonly between 1 and 5 years
• Seizure type: often generalized tonic-clonic
• Neurological exam between seizures: typically normal
• MRI findings: no structural abnormality
• CSF analysis: within normal limits
• Metabolic panel: all values in normal range
• Response to antiepileptic medication: variable; phenobarbital and levetiracetam are the most commonly used agents in cats, though the American College of Veterinary Internal Medicine notes that idiopathic feline epilepsy can be more medication-resistant than canine idiopathic epilepsy in some cases

An important clinical note: diazepam, which is used as a rescue medication for acute seizures, is associated with a rare but potentially fatal acute hepatic necrosis in cats with prolonged oral use. A licensed veterinarian or board-certified veterinary neurologist must supervise all antiepileptic drug selection and dosing in cats.

Key Takeaway: Feline idiopathic epilepsy affects primarily young adult cats and can only be confirmed after all structural, metabolic, toxic, and infectious causes have been excluded through a complete diagnostic workup.

Infectious Diseases That Cause Seizures in Cats

Several infectious agents can directly invade feline central nervous system tissue, trigger severe brain inflammation, and produce seizures as a consequence of that inflammatory destruction. These causes are more common in cats with outdoor access, immunosuppression, or incomplete vaccination histories.

Feline infectious peritonitis (FIP), caused by a mutated form of feline coronavirus, is one of the most recognized infectious causes of neurological disease in cats. The neurological form of FIP involves granulomatous vasculitis of CNS blood vessels, inflammation and protein accumulation in the cerebrospinal fluid, and progressive destruction of brain and spinal cord tissue. Seizures, behavioral changes, progressive ataxia, and cranial nerve dysfunction are all clinical signs of neurological FIP. Young cats and purebred cats, particularly Birman, Ragdoll, and Abyssinian breeds, appear to have higher FIP susceptibility, according to data cited in the Journal of Feline Medicine and Surgery.

Toxoplasma gondii, an obligate intracellular parasite, can encyst in feline brain tissue and cause focal areas of inflammation and necrosis that produce seizures. While cats are the definitive host for this organism and typically shed oocysts without becoming severely ill, immunocompromised cats (those with FIV infection, FeLV infection, or receiving immunosuppressive treatment) can develop symptomatic CNS toxoplasmosis with seizure activity.

Other infectious causes include:

• Cryptococcus neoformans: a fungal pathogen that infects the CNS through the nasal cavity and cribriform plate, causing cryptococcal meningoencephalitis. The polysaccharide capsule of this organism interferes with normal CSF drainage and produces progressive intracranial pressure elevation, cortical dysfunction, and seizures. More common in outdoor cats with soil and pigeon dropping exposure.
• Feline immunodeficiency virus (FIV): directly infects CNS macrophages and microglia, producing chronic low-grade encephalitis that can lower the seizure threshold and, in advanced infection, produce frank seizure events.
• Feline leukemia virus (FeLV): associated with CNS lymphoma (a form of intracranial neoplasia) and with CNS demyelination, both of which can produce seizures.
• Bacterial meningoencephalitis: uncommon in cats but possible following penetrating head trauma, extension of severe otitis media or interna, or hematogenous spread from systemic bacterial infection.

Vaccination against FeLV and routine FIV testing are the primary prevention strategies for the viral causes in this category. Outdoor cats remain at substantially higher risk for all infectious CNS pathogens.

Seizures in Cats and Old Age

New-onset seizures in a cat over 7 to 8 years of age should be treated as structural brain disease or metabolic disease until definitively proven otherwise. This is not pessimism. It reflects the well-established clinical pattern documented in Veterinary Clinics of North America: Small Animal Practice: intracranial neoplasia, particularly meningioma, is one of the most common causes of first-time seizures in geriatric cats.

Feline meningioma is biologically distinct from its human counterpart. In cats, these tumors are frequently located along the dorsal surface of the cerebral hemispheres and in the region of the olfactory bulbs and frontal lobes. They can grow to substantial size before producing obvious clinical signs because cats are adept at compensating for gradual neurological changes. By the time a seizure occurs, the tumor may already be exerting significant mass effect on surrounding cortical tissue.

In older cats, the differential diagnosis also includes:

• Hypertension-related hypertensive encephalopathy (from hyperthyroidism or chronic kidney disease)
• Hepatic encephalopathy from age-related hepatic fibrosis or neoplasia
• Intracranial lymphoma (particularly in FeLV-positive cats)
• Thiamine deficiency (uncommon but possible with certain restricted diets)
• Cerebrovascular events (ischemic or hemorrhagic strokes)

A practical point: feline hyperthyroidism affects an estimated 10 percent of cats over 10 years of age, according to the Cornell Feline Health Center, and systemic hypertension develops in 20 to 30 percent of hyperthyroid cats. This means a significant proportion of older cats presenting with seizures have hypertension as a direct or contributing cause, one that is both treatable and diagnosable with a simple blood pressure measurement in the clinic.

Cats with age-related chronic kidney disease also develop uremia over time, and the uremic toxins that accumulate as renal function declines directly interfere with GABA-A receptor function in the brain, progressively lowering the seizure threshold. An older cat with known kidney disease who begins having seizures has reached a point requiring immediate veterinary reassessment of their renal management plan.

Phases of a Cat Seizure: Pre-Ictal, Ictal, and Post-Ictal

A feline seizure episode has three distinct phases, each reflecting different neurological events in the brain. Understanding all three phases helps cat owners track symptoms accurately, report to their veterinarian with clinical precision, and recognize warning signs that the post-ictal phase has crossed into a medical emergency.

Phase 1: Pre-ictal (Prodromal Phase)
This phase occurs before the seizure begins, sometimes minutes to hours earlier. Cats may show behavioral changes including unusual clinginess, restlessness, hiding, excessive vocalization, apparent anxiety, or subtle repeated movements. Some cats seek out their owner. This phase reflects the early cortical hyperexcitability building before the full discharge event. Not all cats show observable pre-ictal signs, and owners often only recognize this phase in retrospect after witnessing multiple seizures.

Phase 2: Ictal Phase
This is the seizure itself. It reflects the peak of abnormal cortical electrical discharge. Duration in most cats: 1 to 3 minutes. The ictal phase produces the motor signs cat owners find most alarming: rigid limb extension, rhythmic jerking, paddling, jaw clamping, salivation, and loss of consciousness. This phase is driven by uncontrolled sodium channel-dependent neuronal depolarization spreading across the cortex, and it ends when inhibitory mechanisms (including GABA system recruitment and neuronal metabolic exhaustion) terminate the discharge.

Phase 3: Post-Ictal Phase
The post-ictal period follows the seizure and reflects the aftermath of massive neuronal energy expenditure. During this phase, neurons are temporarily depleted of ATP, neurotransmitter stores are depleted, and local cerebral blood flow redistribution creates transient areas of relative functional suppression. Observable signs include:

• Profound disorientation or confusion lasting minutes to hours
• Temporary cortical blindness (the cat walks into walls or cannot track objects)
• Extreme fatigue and prolonged sleep
• Aggressive or fearful behavior not typical for the cat
• Excessive hunger or thirst
• Hiding or vocalization

The post-ictal phase can last from 10 minutes to several hours. A cat that remains profoundly disoriented, unresponsive, or unable to walk after 30 minutes requires immediate veterinary evaluation: this may indicate a prolonged ictal event, status epilepticus, or significant structural neurological injury rather than normal post-ictal recovery.

Key Takeaway: The post-ictal phase in cats can produce hours of disorientation, temporary blindness, and behavioral changes that look alarming but are neurologically expected. However, a cat that does not return to recognizable baseline within 30 minutes needs emergency veterinary care.

Cluster Seizures and Status Epilepticus in Cats

Cluster seizures and status epilepticus are the two most serious presentations of seizure activity in cats, and both require immediate emergency veterinary intervention. Understanding the distinction, and what makes each dangerous, helps cat owners respond without hesitation.

Cluster seizures are defined as two or more individual seizure episodes occurring within a 24-hour period, with the cat regaining consciousness between events. Each individual seizure in a cluster may appear to resolve normally, which sometimes creates a false sense that the cat is recovering. It is not. With each successive ictal event, the brain accumulates neuronal metabolic debt, core body temperature rises (as sustained muscle contractions generate heat), cerebral blood flow demands escalate, and the threshold for the next seizure drops further. Without veterinary intervention, cluster seizures can progress to status epilepticus.

Status epilepticus is a single continuous seizure lasting more than 5 minutes, or repeated seizures between which the cat does not regain normal consciousness. According to guidance cited in the Merck Veterinary Manual, status epilepticus carries a substantially elevated risk of permanent neurological injury and death in cats because of:

• Hyperthermia: sustained muscle activity generates body temperatures that can exceed 40 to 41 degrees Celsius (104 to 106 degrees Fahrenheit), damaging brain tissue directly
• Hypoxia: impaired respiratory function during prolonged ictal activity reduces oxygen delivery to brain tissue
• Hypoglycemia: sustained neuronal firing depletes glucose reserves
• Excitotoxicity: massive glutamate release during prolonged depolarization damages neurons through calcium influx, a process that continues even after the seizure is controlled

Emergency veterinary management of status epilepticus typically involves intravenous benzodiazepine administration (with close monitoring for hepatic effects in cats), phenobarbital loading, active cooling for hyperthermia, glucose support, and oxygen supplementation. This cannot be safely managed at home.

If your cat is seizing continuously for more than 5 minutes or has had two seizures within 24 hours, take your cat to a veterinary emergency clinic immediately. Do not wait.

How Age and Breed Affect Seizure Risk in Cats

Age is the single most powerful predictor of seizure cause category in cats, and it shapes the entire diagnostic decision tree a veterinarian follows from the first examination.

Regarding breed, published data on breed-specific feline epilepsy susceptibility is limited compared to canine data. The Journal of Feline Medicine and Surgery has noted possible higher prevalence of idiopathic epilepsy in Siamese cats, though the sample sizes in published studies remain relatively small. FIP susceptibility has a more robust association with purebred cat populations, particularly Birman, Ragdoll, Abyssinian, Bengal, and Himalayan breeds, likely related to the density of multi-cat breeding environments increasing coronavirus exposure.

Outdoor versus indoor status represents a risk stratification as important as breed. Outdoor cats face direct exposure to organophosphate pesticides, permethrin-treated lawns, toxic plants, infectious pathogens (including Toxoplasma gondii in prey animals and Cryptococcus neoformans in soil), and traumatic brain injury from vehicles or predatory animals. Outdoor cats presenting with first-time seizures should have toxin exposure included prominently in the differential diagnosis regardless of age.

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How Veterinarians Diagnose the Cause of Seizures in Cats

Diagnosing the cause of seizures in cats follows a systematic process that begins with history and physical examination and escalates through laboratory testing and advanced imaging based on initial findings.

To give your veterinarian the most clinically useful information, prepare the following before your appointment:

1. Record the date, time, and duration of every seizure episode, including any that may have occurred while you were asleep (evidence includes post-ictal behavioral changes noticed on waking).
2. Note whether the seizure started with focal signs (one limb twitching, one side of the face moving) or immediately involved the entire body.
3. Describe your cat’s behavior in the hours before the seizure: any unusual hiding, vocalization, or change in gait.
4. Describe the post-ictal period: how long it lasted, what behavioral changes occurred, and whether your cat returned to normal baseline.
5. List all products applied to your cat (including flea prevention, topicals, and any products applied to other pets in the household) and all medications your cat receives.
6. Report any possible toxin exposures: outdoor access areas, houseplants, unsecured medications, cleaning products.
7. Bring any previous veterinary records, especially blood work, blood pressure measurements, and prior diagnoses.

The diagnostic sequence a veterinarian typically follows:

A board-certified veterinary neurologist (DACVIM Neurology) should perform or supervise MRI interpretation and CSF analysis for any cat where intracranial structural disease is suspected. These specialists have advanced training in feline neurological diagnosis that general practice veterinarians typically refer out for complex cases.

Key Takeaway: The diagnostic process for seizures in cats is sequential and evidence-driven. A blood panel and blood pressure measurement on the first visit can identify most metabolic causes. MRI is the gold standard for confirming or ruling out structural brain disease when initial bloodwork is unremarkable.

Emergency Signs: When to Take Your Cat to the Vet Immediately

Certain presentations of seizures in cats represent neurological emergencies where the window for effective treatment is short and deterioration can be rapid.

Take your cat to a veterinary emergency clinic immediately if any of the following occur:

• A single seizure lasts more than 5 minutes without stopping: this meets the clinical definition of status epilepticus and carries significant risk of brain injury from hyperthermia, hypoxia, and excitotoxic neuronal damage
• Two or more seizures occur within a 24-hour period, even if the cat appears to recover between episodes (cluster seizures escalate rapidly)
• Your cat does not return to recognizable behavioral baseline within 30 minutes of a seizure ending: prolonged post-ictal impairment can indicate ongoing seizure activity, severe cerebral edema, or significant neurological injury
• The seizure is accompanied by other signs including sudden collapse, extreme labored breathing, pale or blue-tinged gums, or profound weakness: these suggest a cardiovascular or respiratory emergency concurrent with or mimicking seizure activity
• You have reason to believe your cat was exposed to a toxin such as a dog flea prevention product containing permethrin, antifreeze, or any other potentially toxic substance in the hours or days before the seizure
• Your cat is a known or suspected FIP-positive cat experiencing new neurological signs
• The cat is a senior cat (over 8 years) having their first-ever seizure episode

If toxin exposure is possible, call the ASPCA Animal Poison Control Center at 888-426-4435 immediately. Do not wait for symptoms to worsen. A consultation fee may apply but can be the difference between effective early intervention and irreversible toxicological injury.

These presentations require emergency veterinary assessment, not an urgent care appointment scheduled for the following morning. Status epilepticus in cats treated within the first 30 minutes has a substantially better outcome than cases treated after an hour of continuous seizure activity.

What to Do During and After Your Cat Has a Seizure

Your role during a cat seizure is to keep your cat safe from physical injury, time the episode precisely, and avoid any action that puts you or your cat at greater risk. What you observe during and after the seizure is clinical data your veterinarian needs.

During the seizure:

1. Stay calm. Your cat cannot respond to reassurance during the ictal phase, but your calm presence keeps you from making decisions that could cause injury to you or the cat.
2. Move all hard objects, furniture edges, and stairs away from your seizing cat immediately. Do not attempt to restrain the cat’s limbs or body. Restrained seizure activity increases the risk of musculoskeletal injury and puts your hands near the cat’s snapping jaws.
3. Do not place your fingers near your cat’s mouth. The belief that cats can swallow their tongue during a seizure is false. Attempting to open their mouth risks a severe bite injury and does not help the cat.
4. Time the seizure from the first visible sign to the end of motor activity. Use a clock or phone timer. This is the single most important piece of information for the veterinarian’s assessment.
5. If the seizure has lasted more than 5 minutes, begin transport to an emergency veterinary clinic while the seizure is still occurring. Do not wait for it to stop on its own.

After the seizure:

• Keep your cat in a quiet, dim room during the post-ictal phase. Bright lights and noise can increase agitation during cortical recovery.
• Do not offer food or water until your cat is fully alert and coordinating movements normally. Post-ictal cats can inhale food or water due to impaired pharyngeal coordination.
• Monitor your cat continuously for at least one hour after the seizure ends.
• Note all post-ictal behavioral signs: duration of disorientation, any temporary blindness, vocalization, aggression, or abnormal gait. Write them down for your veterinarian appointment.
• Contact a licensed veterinarian within 24 hours for any first-time seizure, even if the cat appears fully recovered. Do not wait to see if it happens again.

Quick Tip:

• Keep a seizure log for any cat with a known or suspected seizure history: date, time, duration, description of motor activity, post-ictal duration, and any possible triggers (new products, dietary changes, stress events)
• Photograph or briefly video the episode if it is safe to do so while keeping distance. A 30-second video of the ictal phase gives a veterinarian clinical information that a verbal description often cannot fully convey.
• Senior cats experiencing their first seizure should have a veterinary appointment the same day, not the following week.

Frequently Asked Questions About What Causes Seizures in Cats

What is the most common cause of seizures in cats?

The most common cause of seizures in cats varies by age: in cats under 5 years, idiopathic epilepsy is the leading diagnosis, while in cats over 7 years, intracranial structural disease (particularly meningioma) and metabolic conditions (hypertensive encephalopathy from hyperthyroidism or chronic kidney disease) predominate.
No single cause can be identified without veterinary diagnostic testing including blood work, blood pressure measurement, and often MRI.
A licensed veterinarian should evaluate any cat that has had a seizure, even a first episode that appeared to resolve completely.

Can a cat recover from a seizure on their own?

Most individual seizure events in cats end on their own within 1 to 3 minutes, after which the cat enters a post-ictal recovery phase that can last minutes to several hours.
However, recovering from the physical event does not mean the underlying cause has resolved, and without veterinary diagnosis and treatment the seizure will almost certainly recur.
A seizure lasting more than 5 minutes or a cat that does not return to baseline within 30 minutes requires immediate emergency veterinary care, not monitoring at home.

How long do seizures in cats usually last?

Most feline seizures last between 1 and 3 minutes during the ictal (active motor activity) phase.
Any seizure lasting more than 5 minutes meets the clinical definition of status epilepticus, which is a veterinary neurological emergency requiring immediate treatment.
Post-ictal behavioral changes (disorientation, temporary blindness, hiding) can persist for minutes to several hours after the ictal phase ends and are part of the normal neurological recovery process.

What should I do if my cat has a seizure for the first time?

Keep your cat safe from hard surfaces and obstacles during the episode, time it precisely, and do not attempt to restrain the cat or place fingers near its mouth.
After the seizure ends, contact a licensed veterinarian the same day for an evaluation appointment, even if your cat appears to have fully recovered.
If the seizure lasts more than 5 minutes or you suspect toxin exposure, take your cat to a veterinary emergency clinic immediately and call the ASPCA Animal Poison Control Center at 888-426-4435 if a toxin may be involved.

Are seizures in cats always a sign of epilepsy?

Seizures in cats are not always a sign of epilepsy. Epilepsy is only one cause category among many, and in cats over 7 years, structural brain disease and metabolic conditions are more common causes than idiopathic epilepsy.
The term epilepsy specifically refers to a condition of recurrent seizures, and feline idiopathic epilepsy is a diagnosis of exclusion confirmed only after all other causes have been ruled out through a full diagnostic workup.
Cats with seizures should have a complete evaluation before any seizure disorder is labeled idiopathic epilepsy.

What toxins are most likely to cause a seizure in a cat?

Permethrin, a synthetic pyrethroid found in dog-labeled flea prevention products, is one of the most common toxins causing seizures in cats and is particularly dangerous due to the feline liver’s limited ability to detoxify it.
Other common toxin causes include organophosphate and carbamate insecticides, ethylene glycol (antifreeze), certain houseplants (lilies cause acute kidney failure with secondary neurological effects), and human medications including NSAIDs and antidepressants.
If toxin exposure is suspected, call the ASPCA Animal Poison Control Center at 888-426-4435 immediately and proceed directly to a veterinary emergency clinic.

Seizures in cats are a signal from the nervous system that something has disrupted the brain’s ability to regulate its own electrical activity. The cause can be as specific and treatable as high blood pressure from an overactive thyroid gland, or as serious as a growing brain tumor. The only way to tell the difference is a structured veterinary evaluation that works through the most likely causes systematically based on your cat’s age, history, and clinical presentation.

The single most useful thing you can do after a seizure episode is document what you observed and contact a licensed veterinarian the same day. If your cat is an older cat or the episode lasted more than five minutes, that contact needs to happen immediately at an emergency veterinary clinic. A board-certified veterinary neurologist becomes the appropriate specialist if the initial workup does not reveal a metabolic or toxic cause and structural brain disease is suspected.

Your cat cannot tell you what is wrong. The observations you record, the timeline you document, and the speed with which you seek veterinary evaluation are the things that give a veterinarian the information they need to diagnose the cause accurately and start appropriate treatment

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