A 55-year-old hypertensive woman presents with a red right eye, pulsatile proptosis, an audible bruit over the closed eyelid, and dilated corkscrew episcleral vessels. Visual acuity is reduced and intraocular pressure is 34 mmHg. The MOST likely diagnosis is:
- A Thyroid eye disease with congestive orbitopathy
- B Carotid-cavernous fistula ✓
- C Cavernous haemangioma
- D Orbital varix
Correct answer: B. Carotid-cavernous fistula
Explanation
B carotid-cavernous fistula shunts arterial blood into the cavernous sinus, raising orbital venous pressure and producing pulsatile proptosis, an orbital bruit, arterialised corkscrew conjunctival vessels, raised intraocular pressure, and cranial nerve palsies. Thyroid orbitopathy gives non-pulsatile proptosis without a bruit, while cavernous haemangioma and orbital varix are non-pulsatile space occupying lesions without arterialized vessels.
Reference: Kanski's Clinical Ophthalmology, 9th ed.
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