What should you know about tonic clonic seizure?

The word tonic describes a phase in which muscles tighten. Clonic describes repeated muscle contractions that produce jerking movements. A person may fall, become unresponsive, breathe noisily, or have saliva around the mouth. Afterward, confusion, sleepiness, headache, muscle soreness or a bitten tongue can occur while awareness returns.

One seizure does not by itself explain why it happened or establish epilepsy. Causes can include a temporary change in blood sugar, alcohol withdrawal, infection, head injury, medication effects or an electrical condition affecting the brain. A clinician uses the event history and examination to guide assessment.

Move nearby hard or sharp objects away, cushion the head, loosen tight clothing around the neck and note when the movements begin. Do not restrain the person, put anything in the mouth, or offer food, drink or tablets until they are fully alert. When the jerking stops, turn the person onto their side and stay with them while they recover.

Call emergency services if the seizure lasts five minutes or longer, another seizure follows without recovery, the person has trouble breathing, is seriously injured, is pregnant, or the event happened in water. Urgent assessment is also needed for a first seizure, a persistent severe headache, fever with a stiff neck, or continuing confusion.

Ask what might have triggered the event, whether tests such as blood tests or brain imaging are needed, and whether a specialist review is appropriate. Mention any recent illness, missed medicines, substance withdrawal, sleep loss or unusual movements witnessed by another person.