A 78-year-old woman presented with proptosis and double vision for 2 weeks. One month prior, she had fallen and suffered a skull fracture with a nonsurgical epidural hematoma. Visual acuity was 20/20 bilaterally. Her right pupil was 2 mm and reactive, and her left pupil was 4 mm and fixed. She had ptosis, inability to adduct, and limited elevation of the left eye (Figure 1). A bruit was auscultated over the left eye. The remainder of her neurological examination was normal. A computed tomography (CT) angiogram of the brain was obtained (Figure 2).
Carotid-cavernous sinus fistula. A carotid-cavernous sinus fistula develops when the carotid artery leaks into the cavernous system, usually over days to weeks, increasing venous pressure and compressing the cavernous sinus contents. 1 Most occur after blunt or penetrating head trauma, although they can also occur spontaneously. The classic triad of symptoms is chemosis, exophthalmos, and orbital bruit. Patients may also present with ophthalmoplegia, facial sensory deficit, ptosis, photophobia, or blindness. Our patient presented with a cranial nerve III palsy. CT angiography is the study of choice to diagnose a carotid-cavernous sinus fistula and commonly demonstrates proptosis, an engorged superior ophthalmic vein, and thick extraocular muscles. 2
This diagnosis is important to consider in a patient with pulsating proptosis or an atypical red eye, because patients risk secondary glaucoma and blindness. 3 Misdiagnoses include arteriovenous malformations, aneurysms, multiple sclerosis, infections, and malignancies. Our patient underwent cerebral angiography with coil embolization of her fistula, with resolution of her symptoms.
Competing interests: None declared.