PAINFUL OCULOMOTOR PALSY CAUSED BY POSTERIOR-DRAINING DURAL CAROTID-CAVERNOUS FISTULAS

Background: Carotid cavernous fistulas cause conjunctival hyperemia an d orbital soft-tissue swelling because of increased flow directed ante riorly in ophthalmic veins. Less well recognized is that when fistular flow is directed posteriorly, these congestive features will be absen t and the diagnosis of the ''white-eyed shunt'' will be missed unless angiography is performed. Methods: Two patients who had oculomotor ner ve palsies caused by posteriorly draining dural carotid cavernous fist ulas were studied, and the 28 previously described cases were reviewed . Results: One patient had a chronic painful palsy of the sixth crania l nerve, and the other, a palsy of the third cranial nerve. Cerebral a ngiography disclosed the fistulas. The clinical and imaging features o f these cases conform to those of the 28 previously reported white-eye d shunts. Angiographic features do not explain why some posterior-drai ning fistulas cause sixth-nerve palsies and others cause third- (or ra rely, fourth-) nerve palsies. Conclusions: Dural carotid cavernous fis tulas that drain primarily into the inferior petrosal sinus may cause painful oculomotor palsies that elude diagnosis because they lack cong estive orbito-ocular features. Treatment by embolization leads to more rapid resolution of manifestations.