A seizure is a sudden, uncontrolled electrical disturbance in the brain that temporarily disrupts normal function, causing involuntary muscle activity, altered consciousness, or abnormal behaviour. Seizures are a symptom, not a diagnosis — they can result from epilepsy, toxin exposure, metabolic disease, brain tumours, infections, or trauma. A seizure lasting more than 5 minutes is a medical emergency.
Seizures have three phases. The pre-ictal phase (aura) occurs minutes to hours before: the pet may seem anxious, clingy, or restless. The ictal phase is the seizure itself: typically 30 seconds to 2 minutes of involuntary muscle activity (paddling, convulsing), altered consciousness, loss of bladder or bowel control, and excessive salivation. The post-ictal phase follows: disorientation, temporary blindness, excessive drinking, and profound fatigue lasting minutes to hours.
A single brief seizure (under 5 minutes) in a dog or cat that recovers normally is not an immediate emergency, but requires veterinary evaluation within 24 hours. A seizure lasting more than 5 minutes (status epilepticus), multiple seizures within 24 hours (cluster seizures), or failure to recover full consciousness between seizures are all emergency situations requiring immediate veterinary intervention. Status epilepticus causes brain damage and death without prompt treatment.
Common causes vary by age. Young dogs (under 1–3 years) with idiopathic epilepsy will typically have no identifiable underlying cause and seizures that are manageable with medication. Older dogs developing new seizures warrant more thorough investigation for metabolic disease, brain tumour, or toxin exposure. In cats, seizures are less common and almost always have an identifiable underlying cause worth investigating.
Three phases: Pre-ictal (aura), ictal (seizure), post-ictal (recovery)
Most common cause in young dogs: Idiopathic epilepsy
Most common seizure cause in cats: Almost always identifiable — requires investigation
Frequently Asked Questions about Seizure
Q: What should I do if my pet is having a seizure?
Stay calm. Do not put your hand in their mouth — they cannot swallow their tongue and you risk being bitten. Move objects away from them to prevent injury. Time the seizure — duration is critical information for your vet. Keep the environment quiet and dim. After the seizure ends, call your vet. If the seizure lasts more than 5 minutes or if multiple seizures occur, go to an emergency vet immediately.
Q: Will my pet remember having a seizure?
No. Dogs and cats have no memory of the ictal phase itself. The post-ictal confusion and disorientation are the direct effect of the electrical disruption on normal brain function — they are temporary and resolve as the brain recovers.
Q: If my dog has one seizure, do they need lifelong medication?
Not necessarily. Many vets recommend starting anticonvulsant medication after two or more seizures within a six-month period, after a single prolonged or severe seizure, or after cluster seizures. A single brief isolated seizure may be monitored rather than treated immediately. This decision is made case by case.
⚠ Medical Disclaimer: This glossary entry is for educational purposes only
and does not constitute veterinary advice. Always consult a licensed veterinarian for diagnosis
and treatment of your pet's health conditions.