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Cavernous Sinus Thrombosis


James Garrity

, MD, Mayo Clinic College of Medicine

Last full review/revision Jul 2020| Content last modified Jul 2020

Cavernous sinus thrombosis is a very rare disorder in which a blood clot (thrombosis) forms in the cavernous sinus (a large vein at the base of the skull).

  • Cavernous sinus thrombosis is usually caused by the spread of bacteria from infections of the face and orbit (including the skin of the nose), orbit, or sinus.
  • Symptoms include head and facial pain, visual disturbances, rapidly bulging eyes, and high fever.
  • The diagnosis is based on symptoms and the results of magnetic resonance imaging or computed tomography.
  • Even with treatment, the disorder can result in severe after-effects or be fatal.
  • High doses of antibiotics are given to eliminate the infection.

(See also Introduction to Eye Socket Disorders.)

The cavernous sinus is a large vein at the base of the skull, behind the eyes. This vein drains blood from veins in the face. The cavernous sinus is not one of the air-filled sinuses around the nose (the nasal sinuses).

Cavernous sinus thrombosis (CST) can affect the cranial nerves 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).

Causes of Cavernous Sinus Thrombosis

Cavernous sinus thrombosis 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), orbital cellulitis, 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 rims of the eyes serious.

Symptoms of Cavernous Sinus Thrombosis

Cavernous sinus thrombosis causes symptoms such as abnormally bulging eyes (proptosis) that occurs over days, 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.

Diagnosis of Cavernous Sinus Thrombosis

  • Magnetic resonance imaging or computed tomography
  • Blood culture
  • Spinal tap (lumbar puncture)

To diagnose cavernous sinus thrombosis, doctors do magnetic resonance imaging (MRI) or computed tomography (CT) of the nasal sinuses, eyes, and brain. To identify the bacteria, a blood sample is sent to a laboratory to be cultured. A spinal tap may also be done.

Prognosis of Cavernous Sinus Thrombosis

Even with treatment, cavernous sinus thrombosis can still be life threatening. About 30% of all affected people, and about 50% of affected people who also have sinusitis of the sphenoid sinuses, die. Another 30% develop serious after-effects (such as impaired eye movements and double vision, blindness, disability due to stroke, and hypopopituitarism), which may be permanent.

Treatment of Cavernous Sinus Thrombosis

  • Antibiotics by vein
  • Surgery to drain infection
  • Corticosteroids and other supplemental hormones

High doses of antibiotics given by vein (intravenously) are started immediately in people with cavernous sinus thrombosis. 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.

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