An abnormal communication forms between the carotid artery and the cavernous sinus in the brain. Blood under high pressure enters the cavernous sinus causing disruption to the local nerves and backwards flow through veins draining the orbit. This impairs drainage and the orbital tissues become congested and swollen. The fistula may have high or low flow of blood. CCF following trauma is often high flow with sudden onset and dramatic features; spontaneous rupture of connecting vessels may cause high or low flow fistulas. Low flow lesions are often subtle.
Clinical Features
Discomfort or pain around the eye
Swollen conjunctiva
Engorged conjunctival and retinal blood vessels
Double vision
Proptosis
Impaired eye movements
Impaired sight
