What should you know about tonic seizure?

During a tonic seizure, muscles tighten abruptly and the person may become rigid, fall, or lose awareness. The eyes may stare or roll, and breathing can sound unusual while the seizure is happening. A person can be confused, sleepy, or sore afterwards. A seizure may have many possible triggers or causes, including low blood glucose, alcohol withdrawal, infection affecting the brain, or an underlying seizure disorder. The appearance alone cannot identify the cause.

A tonic seizure is different from a seizure with repeated jerking, although seizure types can occur together. Tell a clinician what happened before, during, and after the event, including any warning symptoms, illness, missed medicines, alcohol use, or head injury.

Move hard or sharp objects away, cushion the head, loosen tight clothing around the neck, and note when the seizure begins. Do not hold the person down, put anything in the mouth, or give food, drink, or medicine until they are fully alert. Once the stiffening stops, place them on their side if they are breathing and stay with them. A video recorded from a safe distance can help a clinician, but do not delay emergency help to record it.

Call emergency services if this is the person’s first seizure, the event continues, seizures repeat without recovery, breathing does not return normally, or the person is injured, pregnant, or difficult to wake. Urgent assessment is also needed after a seizure in someone with diabetes, possible poisoning, recent head injury, or signs of a serious infection such as a severe headache, stiff neck, or a new rash. Even when recovery is quick, arrange medical assessment to identify the cause and discuss whether further testing or treatment is needed.

Ask what type of seizure was suspected, whether blood tests or brain imaging are appropriate, how to reduce injury risk at home, and what plan to follow if another event occurs. Ask whether driving, swimming alone, heights, or operating machinery should be avoided until you have been assessed.