What should you know about focal seizure causes?

A seizure begins when a group of brain cells sends abnormal electrical signals. Causes may include a previous stroke, scar, tumour, developmental difference, head injury or infection. Some episodes are linked to reversible changes such as hypoglycaemia, fever, sleep deprivation, missed anti-seizure medicine or withdrawal from alcohol after heavy use. Sometimes testing does not identify a clear cause. A trigger can lower the brain's seizure threshold without meaning that a person has epilepsy. A clinician needs the full event history before drawing conclusions.

Write down what happened before, during and after the event, including sleep, food, medicines, alcohol, illness and any injury. Ask a witness to describe movements and responsiveness; a safe video can be useful if nobody is put at risk. A clinician may check blood sugar and other blood results, review medicines, and consider an EEG or brain imaging. Do not stop prescribed medicine suddenly or attempt to test a suspected trigger yourself.

Get emergency help for a first seizure, an episode that is prolonged or repeats without recovery, a serious injury, breathing difficulty, or persistent confusion. A seizure with severe headache, stiff neck, fever, new weakness or a new rash needs urgent care because meningitis and other serious conditions can affect the brain. A person with diabetes who may have hypoglycaemia needs immediate attention, and alcohol withdrawal can also be dangerous.

Ask which causes fit your history, which tests are useful, whether medicines or sleep patterns could contribute, and how to reduce risk while the assessment is underway. Ask for a written seizure first-aid plan.