Cavernous sinus thrombosis is a very rare disorder in which a blood clot (thrombosis) forms in the cavernous sinus.
The cavernous sinus is a large vein at the base of the brain, behind the eyes. The cavernous sinus is not one of the air-filled sinuses around the nose (the nasal sinuses).
Cavernous sinus thrombosis (CST) is usually caused by the spread of bacteria (usually Staphylococcus aureus) from a facial, dental, or nasal sinus infection. CST can be caused by common facial infections such as small nasal boils around hair follicles (furuncles) or sinusitis of the sphenoid or ethmoid sinuses. Because CST is a possible complication, doctors always consider infections in the area around the nose to the rim of the eyes serious. CST can affect the cranial nerves (see Cranial Nerve Disorders: Overview of the Cranial Nerves) near the cavernous sinus that move the eyes and supply sensation to the face. CST can also lead to an infection of the brain and the fluid around the meninges (meningoencephalitis), brain abscess, stroke, blindness, and an underactive pituitary gland (hypopituitarism—see Pituitary Gland Disorders: Hypopituitarism).
CST causes symptoms such as abnormally bulging eyes (proptosis), swelling of the eyelid, severe headache, facial pain or numbness, impaired eye movements (ophthalmoplegia) with double vision, loss of vision, drowsiness, a high fever, and excessively dilated or uneven pupils. If bacteria spread to the brain, more severe drowsiness, seizures, coma, and abnormal sensations or muscle weakness in certain areas may develop.
Magnetic resonance imaging (MRI) or computed tomography (CT) of the nasal sinuses, eyes, and brain is usually done. To identify the bacteria, a blood sample and samples of fluid, mucus, or pus from the throat and nose are sent to a laboratory to be cultured. A spinal tap (see Symptoms and Diagnosis of Brain, Spinal Cord, and Nerve Disorders: Spinal Tap) may also be done.
Even with treatment, CST can still be life threatening. About 30 to 50% of affected people die and another 30% develop serious aftereffects (such as impaired eye movements and double vision, blindness, disability due to stroke, and hypopopituitarism), which may be permanent.
High doses of antibiotics given by vein (intravenously) are started immediately. The infected nasal sinus may be drained surgically, particularly if the person does not improve after 24 hours of antibiotic treatment. Corticosteroids are sometimes given if the cranial nerves are affected. Corticosteroids and usually other supplemental hormones are given if there is hypopituitarism.
Last full review/revision July 2012 by James Garrity, MD