Syncope in a sentence: what should you know?

Before a faint, someone may notice dizziness, clammy skin, nausea, ringing in the ears, or a greyed-out view. Standing up quickly, heat, pain, fear, dehydration, or not eating can set off a reflex that slows the heartbeat or widens blood vessels. Anaemia or hypoglycaemia can also make fainting more likely, while an abnormal rhythm such as atrial fibrillation may need specific assessment. The word syncope describes the event; it does not explain the cause. A clinician uses the story, examination, blood pressure, and sometimes an ECG to work out what happened.

If warning symptoms start, lie down straight away or sit with your head between your knees if lying down is not possible. Move away from traffic, stairs, water, and other hazards. Someone helping should keep the person flat, protect the head, and check breathing. Nothing should be put in the mouth, and drinks should wait until full alertness returns. Record the setting, trigger, symptoms before the event, witness observations, and recovery time. Book a review after a first faint, an unexplained faint, or repeated episodes.

Seek emergency help for ongoing unresponsiveness, abnormal breathing, chest discomfort, severe breathlessness, a serious fall, new facial or limb weakness, speech difficulty, or a prolonged seizure-like spell. Do so as well if the faint happened during exertion or without any warning, or if there was a fast or irregular heartbeat beforehand. Prompt medical advice is sensible after repeated events and for anyone with heart disease, significant anaemia, diabetes treated with glucose-lowering medicine, or pregnancy.

What details from the event are most useful? Could a medicine, blood pressure change, blood count, glucose level, or rhythm disturbance explain it? Is it safe for me to drive, work at height, exercise, or bathe alone while we investigate?