What should you know about myoclonic seizure?

A jerk may affect one muscle group or several, often in the arms, shoulders or legs. It can feel like a sudden electric shock or an involuntary flinch. The movement is usually very brief, and awareness may remain intact, although myoclonic seizures can occur as part of a broader seizure disorder. Sleep loss, alcohol withdrawal, low blood sugar, some medicines and brain infections can contribute to seizures. A seizure does not by itself identify the cause; assessment may include your history, examination and tests.

Move nearby hazards away, stay with the person and note what happened, including the time, body parts involved and any change in awareness. Do not hold them down, put anything in their mouth or offer food or drink until they are fully alert. If they fall, protect the head and loosen tight clothing. Afterward, let them rest on their side if sleepy and arrange medical advice, especially after a first event. Until reviewed, avoid driving, swimming alone, heights and operating machinery.

Call emergency services if the seizure lasts longer than usual, repeats without recovery, causes a serious injury, happens in water, or breathing does not return normally. Seek urgent care for a first seizure, new confusion, severe headache, fever, stiff neck, weakness or a possible exposure to a toxin. Meningitis can include fever, headache, stiff neck and seizures. Low blood sugar and alcohol withdrawal are also possible triggers and need prompt treatment.

Ask what might have triggered the jerks, whether an electroencephalogram or brain scan is appropriate, and which activities should be restricted while the cause is being assessed. Bring a medicine and substance list, details of sleep and alcohol use, and a witness account or video if safely available.