Three weeks after head trauma, a 28-year-old man develops a red eye with corkscrew episcleral vessels, pulsatile proptosis, a subjective humming sound, and an audible orbital bruit on auscultation. The MOST likely diagnosis is:

• A Carotid-cavernous sinus fistula ✓
• B Cavernous hemangioma of the orbit
• C Orbital arteriovenous malformation
• D Thrombosed orbital varix

Explanation

A direct, high-flow carotid-cavernous fistula typically follows head trauma and shunts arterial blood into the cavernous sinus, producing arterialised episcleral (corkscrew) vessels, pulsatile exophthalmos, chemosis, raised intraocular pressure, and a pathognomonic orbital bruit heard by both patient and examiner. An orbital AVM can cause pulsatile proptosis but is congenital rather than post-traumatic and less classically associated with corkscrew conjunctival vessels plus a bruit.

Reference: Kanski's Clinical Ophthalmology, 9th ed.

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Written and medically reviewed by the StethoPrep medical team.