A 50-year-old woman presents with a painful, pulsatile proptosis of the left eye with an audible bruit. She has a history of head trauma three weeks ago. Colour Doppler imaging reveals arterialized blood flow in the superior ophthalmic vein. The most likely diagnosis is:

• A Cavernous haemangioma of the orbit
• B Orbital cellulitis
• C Carotid-cavernous sinus fistula (CCF) ✓
• D Orbital lymphoma

Explanation

A direct carotid-cavernous sinus fistula (CCF) following head trauma causes pulsatile exophthalmos, an audible bruit (reduced by carotid compression), chemosis, dilated episcleral vessels, raised IOP, and cranial nerve palsies. Arterialized blood flows retrogradely into the superior ophthalmic vein (SOV), which becomes dilated and visible on Doppler. Direct CCFs are high-flow and result from a tear in the internal carotid artery wall within the cavernous sinus; they require endovascular treatment.

Reference: Khurana Comprehensive Ophthalmology, 7th ed.

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Written and medically reviewed by the StethoPrep medical team.