Cavernous sinus thrombosis

A cavernous sinus thrombosis is a rare, life-threatening condition that occurs when a blood clot blocks the cavernous sinus, which is one of the veins that drain blood from your head and brain. It is usually caused by a bacterial infection that has spread from the sinuses, ear, or nose. Symptoms may include headache, eye pain and swelling, red eye, fever, nausea, vomiting, and loss of balance. A cavernous sinus thrombosis can lead to permanent vision loss, coma, or death if left untreated.