A cavernous sinus thrombosis is a blockage by a thrombus (abnormal blood clot) of a venous sinus (widened channel for venous blood) deep within the skull behind an eye socket. Cavernous sinus thrombosis usually occurs as a complication of a bacterial infection in an area drained by the veins entering the sinus. At first, only the veins behind one eye are affected but, within two or three days, the thrombosis may spread behind the other eye. This serious condition has become rare since the advent of antibiotics to treat bacterial infections.

 

Causes

Among the infections that can lead to cavernous sinus thrombosis are cellulitis (a severe skin infection) of the face; infections of the mouth, eye, or middle ear; sinusitis (infection of the air spaces of the facial skull); and septicemia (infection of the bloodstream). Picking at a small, infected pimple at the angle of the nose may also spread infection to the sinus.

 

Rarely, the thrombosis is caused by a tumor pressing on the veins or by polycythemia (an excessive concentration of red cells in the blood).

 

Symptoms

The patient is usually critically ill. The symptoms are severe headache, high fever, pain in and above the affected eye, loss of sensation in the cornea and on the forehead due to pressure on the fifth cranial nerve, and proptosis (protrusion of the eyeball) due to swelling around and behind the eye. Vision may become blurred and eye movements paralyzed due to pressure on the optic nerve and on other cranial nerves controlling the muscles that move the eyes.

 

Treatment

Treatment is with antibiotics to treat the infection and anticoagulants to prevent the blood clot enlarging. Treatment can save vision in the affected eye(s); if untreated, blindness will result, and the infection may prove fatal.