What should you know about blackout seizures?

Blackout episodes need careful assessment because fainting and seizures can look similar but require different evaluation. A faint usually follows reduced blood flow to the brain and is often brief, while a seizure results from abnormal electrical activity in the brain. Loss of awareness, stiffening, rhythmic jerking, tongue injury, or prolonged confusion can help a clinician distinguish them, but no single sign is decisive.

Before an ordinary faint, some people notice warmth, nausea, sweating, blurred vision, or light-headedness. Recovery commonly begins quickly after lying down. A seizure may happen without warning and can involve staring, unusual movements, loss of bladder control, or confusion after awareness returns. Similar symptoms may also occur with dehydration, low blood sugar, anaemia, or an abnormal heart rhythm. These conditions can present with blackouts but are not diagnosed from the symptom alone.

Protect the person from nearby hazards and lower them gently to the floor. Turn them on their side if they are unconscious or having jerking movements, loosen tight clothing around the neck, and observe the time. Do not restrain them, put anything in their mouth, or offer food or drink until they are fully alert. Afterward, record what happened before, during, and after the event, including medicines, illness, missed meals, and injuries.

Call emergency services if the person does not regain awareness promptly, has repeated episodes without recovering, has difficulty breathing, is seriously injured, or the event occurs during exercise. Urgent assessment is also needed for a first suspected seizure, a new blackout with chest pain or palpitations, or an episode in pregnancy. Arrange a medical review after any unexplained blackout, even if recovery was quick.

Ask whether the description fits fainting, seizure, or another cause; whether an electrocardiogram, blood tests, or neurological assessment is appropriate; and which activities should be avoided until the cause is clearer. Bring a witness account or a recording made from a safe distance, plus a list of medicines and supplements.