Vasovagal syncope is the most common cause of fainting: a reflex drops the heart rate and widens the blood vessels, so blood flow to the brain falls for a short time. It is usually triggered by long standing, heat, pain, the sight of blood or strong emotion, and recovery is quick.
Key symptoms
- Warning signs before fainting: warmth, sweating, nausea, tunnel vision
- Brief loss of consciousness with a fall
- Quick recovery, sometimes with tiredness afterward
- A clear trigger such as standing in a hot room or seeing blood
What you find on exam
- Orthostatic vital signs
- Heart exam for murmurs of aortic stenosis or hypertrophic cardiomyopathy
- Neurologic exam
- Look for injuries from the fall
Tests
- 12-lead ECG in every patient: QT, pre-excitation, Brugada pattern, heart block
- Glucose, pregnancy test and hemoglobin when relevant
- Echocardiogram or rhythm monitoring only if heart disease is suspected
- Tilt table test for recurrent cases with an unclear cause
Treatment basics
- Reassurance and education about the benign cause
- Lie down or sit at the first warning signs
- Counterpressure maneuvers: crossing the legs, tensing the arms, squeezing the hands
- More fluids and salt if blood pressure allows; avoid known triggers
- Review drugs that lower blood pressure
Red flags
- Fainting during exercise or while lying down
- Palpitations or chest pain before fainting, or no warning at all
- Family history of sudden death or an abnormal ECG
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Sources: NCCPA PANCE Content Blueprint; NBOME COMLEX-USA clinical presentations; NASEMSO National Model EMS Clinical Guidelines. Written by Making Synapses. Making Synapses is not affiliated with these organizations.