Vasovagal syncope triggered by pain

Sudden, intense, or prolonged pain can cause an automatic nervous-system reaction. Blood pressure may fall and the heartbeat may slow briefly, reducing blood flow to the brain. Before fainting, a person may feel hot, sweaty, nauseated, weak, or light-headed, with blurred or narrowed vision. Pain-triggered fainting can happen during an injury, injection, wound care, or a painful bowel movement. The pain itself still needs an explanation, and fainting without warning can point to another problem.

Stop the painful activity and lie flat or on your side in a safe area; do not try to walk it off. Keep the airway clear and have someone monitor breathing. After recovery, rise slowly and do not return to the trigger until the painful cause has been assessed. A clinician can examine the injury or illness, review medicines, and consider blood pressure, blood count, glucose, and heart-rhythm checks. Never give food or drink to someone who is not fully awake.

Call emergency services for severe injury, uncontrolled bleeding, chest pain, breathing difficulty, a severe headache, seizure-like movements, new weakness, confusion, or failure to wake normally. Seek prompt medical review if pain is severe or unexplained, the faint repeats, it occurs during exertion, or there was no warning. Arrange assessment after a first faint even if recovery was quick.

Ask what caused the pain, whether you need an electrocardiogram or blood tests, how to prevent fainting during future procedures, which pain relief is appropriate, and when normal activity is safe.