The cavernous sinuses are cavities within the skull behind each eye socket. They contain a network of veins, an artery and several nerves.
Cavernous sinus thrombosis is a blood clot that forms in a blood vessel in the cavernous sinus. It is usually caused by a bacterial infection that has spread from a nearby area, such as the ears, eyes or nose. The condition is extremely rare.
Cavernous sinus thrombosis can cause pain around the eye, loss of vision and bulging of your eyes, among other symptoms (see Symptoms, above, for more information).
If you experience these signs, contact your GP straight away.
How does infection cause a blood clot to occur?
Any infection on your face, such as infection from a pimple or boil in the nostril or on the upper lip or nose, may cause inflammation (swelling) in that area. This is called cellulitis (see Useful links for more information about cellulitis).
From this inflammation, infection may spread to one of the cavernous sinuses. If this happens, the blood in the sinus may turn into an infected clot (see Causes, above).
Who is affected?
Cavernous sinus thrombosis can affect people of any age. It is not contagious or inherited.
Outlook
Cavernouse sinus thrombosis can be life-threatening and requires immediate treatment.
It can be easily treated with high doses of antibiotic drugs, which are given intravenously (directly into your vein) as soon as possible (see Treatment, above).
If the condition does not improve, the sinus may be drained surgically.
However the survival rate has improved dramatically since high-dose antibiotics were introduced as the main treatment.
Vein
Veins are blood vessels that carry blood back to the heart from the rest of the body.
Tissue
Body tissue is made up of groups of cells that perform a specific job, such as protecting the body against infection, producing movement or storing fat.
Inflammation
Inflammation is the body's response to infection, irritation or injury. It causes redness, swelling, pain and sometimes a feeling of heat in the affected area.
Contagious
Contagious is when a disease or infection can be easily passed from one person to another.
