Cavernous sinus thrombosis is a blood clot in the cavernous sinus. The cavernous sinus is a cavity at the base of the brain that contains a vein, several nerves, and other structures. The vein carries deoxygenated blood from the brain and face back to the heart.

The vein and cavity run between the large bone at the base of the skull (sphenoid bone) and temporal bone (near the temple).

The cause of cavernous sinus thrombosis is usually a bacterial infection that has spread from the sinuses, ears, eyes, nose, or skin of the face.

• Loss of vision
• Drooping eyelids
• Bulging eyeballs
• Inability to move one's eye in a particular direction

Tests that may be ordered include:

• Sinus x-ray
• Head computed tomography (CT) scan
• Brain magnetic resonance imaging (MRI)

It is treated with high-dose intravenous (through a vein) antibiotics. Sometimes surgery is needed to drain the infection.

Cavernous sinus thrombosis can be fatal. However, the death rate of this condition has improved tremendously since the introduction of antibiotics.

Call your doctor right away if you have:

• Eye pain
• Loss of vision
• Bulging of your eyes
• Drooping eyelids
• Inability to move your eye in any particular direction