A red eye and then a really red eye.

A 90-year-old woman presented with a 4-week history of a presumed infectious conjunctivitis resistant to topical antibiotic medications. Examination revealed tortuous, dilated conjunctival vessels in the right eye, retinal hemorrhages, and an orbital bruit suggestive of a carotid-cavernous sinus fistula (CCF). While awaiting a magnetic resonance imaging study, she returned to the clinic the next day with a painful, swollen right eye and an intraocular pressure of 69 mm Hg. A cerebral arteriogram confirmed a direct CCF. Because of the tortuosity of the systemic vascular anatomy, a right carotid artery cut-down with balloon occlusion was performed with successful closure of the fistula and prompt resolution of the orbital congestion. This case illustrates the spectrum of subtle to conspicuous ocular manifestations that can be seen in patients with CCF and its potential to present as an emergency. CCF should be included in the differential diagnosis of an "atypical" red eye. Recognition of arteriolized conjunctival vessels and auscultation of an orbital bruit raises the possibility of a CCF, requiring prompt diagnostic studies.