THE majority of reported carotid artery cavernous sinus fistulae are found to be secondary to head trauma, a few apparently occurring spontaneously.1,2
The clinical picture is characterized by pounding headaches, exophthalmos (usually pulsating), chemosis, diminished visual acuity, and paralysis of one or more of the occular muscles. In several cases severe epistaxis is a paramount feature.3 Occasionally the patient may complain of a roaring head noise and auscultation over the protruding eye will reveal the presence of a bruit.
There are two major pathophysiological types of carotid cavernous fistulae, which may be differentiated by angiographic study. In the first, most of the blood from the carotid artery is shunted to the cavernous sinus. The patient will become hemiplegic immediately if there is insufficient collateral circulation by the way of the anterior and posterior communicating arteries. The absence of hemiplegia would suggest that enough blood is reaching the affected