Head Bruit: Causes, Significance & Evaluation

A bruit is an audible vascular sound from turbulent blood flow. A bruit perceived in the head (cranial bruit) is never normal and warrants investigation.

Potential Causes

• Arteriovenous malformation (AVM): high‑flow nidus; continuous or systolic bruit.
• Dural arteriovenous fistula (dAVF): arterialized cortical veins; pulsatile tinnitus.
• Carotid artery stenosis / dissection: systolic bruit over neck radiating to skull.
• Venous sinus stenosis / high jugular bulb: venous hum (diastolic, positional).
• High cardiac output states: anemia, thyrotoxicosis, pregnancy, AV fistula.
• Tumor vascularity: meningioma, paraganglioma.

Evaluation

1. Auscutlation: timing (systolic/diastolic/continuous), location, radiation.
2. Non‑invasive: Doppler ultrasound (carotids), MRA/CTA.
3. Gold standard: digital subtraction angiography (DSA).
4. Audiometric evaluation for pulsatile tinnitus.

Red Flags

• Pulsatile tinnitus (especially unilateral)
• Focal neurologic deficits
• Thunderclap headache
• Cognitive change

Management

Depends on etiology: endovascular embolization (AVM, dAVF), stenting (stenosis), surgery, observation (benign venous hum).