What Is Seizure?
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.
Understanding Seizure
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.