A 34-year-old woman after head injury develops left-sided proptosis with an audible thrill over the closed eyelid, conjunctival corkscrew vessels, and a raised intraocular pressure. Pulsations are visible on slit-lamp examination of the iris. The MOST likely diagnosis is:
- A Thyroid eye disease with congestive orbitopathy
- B Carotid-cavernous fistula ✓
- C Orbital arteriovenous malformation
- D Cavernous sinus thrombosis
Correct answer: B. Carotid-cavernous fistula
Explanation
Direct carotid-cavernous fistula after trauma shunts arterial blood into the cavernous sinus, engorging the superior ophthalmic vein. This gives pulsatile proptosis, an orbital bruit or thrill, arterialised corkscrew episcleral veins, raised intraocular pressure, and sometimes a bruit heard by the patient. Thyroid orbitopathy lacks the bruit and pulsation, and cavernous sinus thrombosis is infective, febrile, and causes cranial nerve palsies rather than an arterial thrill.
Reference: Kanski's Clinical Ophthalmology, 9th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.