Neuro syncope: what to know

Neuro syncope is a brief faint caused by a temporary reduction in blood flow to the brain, often after a trigger. A person may feel warm, sweaty, nauseated, light-headed or have blurred vision before losing consciousness. Recovery is often quick after lying down, but a first faint still deserves medical assessment.

The nervous system normally adjusts heart rate and blood pressure when you stand or face stress. With neuro syncope, that response can briefly slow the heart or widen blood vessels, so the brain receives less blood. Common triggers include prolonged standing, heat, pain, emotional distress, seeing blood, or a medical procedure. Dehydration, missed meals and some medicines can make an episode easier to trigger. Other explanations, including anaemia, an irregular rhythm such as atrial fibrillation, or low blood sugar, may need to be considered.

Stop what you are doing and lie flat with your legs raised if possible. If lying down is unsafe, sit and lower your head between your knees. Loosen tight clothing, move away from heat and tell someone nearby. Do not stand suddenly after symptoms settle. A clinician may ask about the trigger, posture, medicines, food and fluids, injuries, and what witnesses saw; checking blood pressure, pulse and an electrocardiogram can help separate causes.

Call emergency services if fainting occurs during exercise, causes a serious injury, follows chest pain, severe breathlessness or a racing heartbeat, or if the person does not wake promptly. Seek urgent assessment for a faint without warning, repeated episodes, fainting while lying down, new neurological symptoms, or a family history of sudden cardiac death. Arrange a routine appointment after any unexplained first episode.

Ask whether the episode fits neuro syncope, which warning signs should prompt emergency help, whether your medicines or hydration need review, and whether heart-rhythm testing is appropriate. Bring an episode timeline and a witness account if available.