The two cavernous sinuses are venous drainage areas on either side of the pituitary gland, at the base of the skull. Several cranial nerves and the internal carotid artery pass through the sinus. Thrombosis, or clotting, in the sinus can be caused by a generalized tendency to clot, for example in women who take birth control pills, or by an infection in adjacent areas. Cavernous sinus thrombosis causes symptoms by putting pressure on the structures inside it and around it, and by disrupting the flow of venous blood from the face and eye area.
Headache and Seizures
Symptoms usually evolve more slowly than in an arterial stroke. According to a study published in the "Quarterly Medical Journal," they develop gradually, over several hours, sometimes over several weeks. Headache is almost invariably present, and is often located over the eye and cheek on the affected side. Seizures occur in about half of the patients. They can be focal, meaning that one limb might convulse, or generalized, which means that the convulsion spreads to the entire body and the patient loses consciousness.
Eye Symptoms
Eye pain develops on the side of the thrombosis, accompanied by swelling and redness of the conjunctiva. Later the eye may bulge forward, a condition known as exophthalmus. Eye muscles are weakened and eye movement can be paralyzed, as a result of pressure on the cranial nerves that control eye movement. The pupil can be small or enlarged. Pressure on the optic nerve leads to impaired vision. These symptoms may later appear in the other eye.
Late Symptoms
As the condition spreads, confusion may appear. The patient may sink into a coma. In a study quoted by the "Quarterly Medical Journal," 15 percent of patients were comatose and an additional 40 percent had a reduced level of consciousness. The pituitary gland may be compressed, leading to hypopituitarism, in which all the hormones cease to be released from the pituitary. Unless treated, hypopituitarism can lead to shock and death. According to Merck.com, about 30 percent of those with cavernous sinus thrombosis die. Of the survivors, about half develop complications, including blindness, paralysis of eye movement, and hypopituitarism.
References
- "Quarterly Journal of Medicine"; Cerebral Venous Sinus Thrombosis; J. Kimber; 2002
- Merck.com: Cavernous Sinus Thrombosis
- "Adams and Victor's Principles of Neurology"; Maurice Victor and Allan Ropper; 2001
