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Cerebral Venous Thrombosis
By: Dr. William Alvin McElveen |
Background
Thrombosis of the venous channels in the brain is an uncommon cause of cerebral infarction relative to arterial disease but is an important consideration because of its potential morbidity. Venous thrombosis may occur with headache and cranial nerve palsies. Newer imaging procedures have led to easier recognition of venous sinus thrombosis, offering the opportunity for early therapeutic measures. Venous thrombosis also may be associated with other medical complications that require therapeutic intervention.Pathophysiology
Knowledge of the anatomy of the venous system is essential in evaluating patients with venous thrombosis, since symptoms associated with the condition are related to the area of thrombosis. Cerebral infarction may occur with cortical vein or sagittal sinus thrombosis secondary to tissue congestion with obstruction. Lateral sinus thrombosis may be associated with headache and a pseudotumor cerebri�like picture. Extension into the jugular bulb may cause jugular foramen syndrome; cranial nerve palsies may be seen in cavernous sinus thrombosis as a compressive phenomenon. Cerebral hemorrhage also may be a presenting feature in patients with venous sinus thrombosis.Frequency
Incidence of cerebral venous thrombosis (CVT) is difficult to determine. Generally, it is believed to be an uncommon cause of stroke. However, with the advent of newer imaging techniques, the reported incidence is likely to increase as less severe cases are found. In 1973, Towbin reported CVT in 9% of 182 autopsies. In 1995, Daif reported a frequency in Saudi Arabia of 7 cases per 100,000 hospital patients. The ratio of venous to arterial strokes has been found to be 1:62.5.Mortality / Morbidity
Mortality in untreated cases of venous thrombosis has been reported to range from 13.8-48%; this high mortality rate may be a reflection of clinical severity at entrance into the study. Between 25% and 30% of patients have full recovery.More recently, a Portuguese study group prospectively analyzed 91 consecutively admitted patients from 1995 to 1998 over a mean 1-year follow-up interval (Ferro, 2002). Of the patients analyzed, 7% died in the acute phase, 1% died during the one year follow-up, 82% recovered completely, and 1% were dependent; 59% developed thrombotic events during the follow-up, 10% had seizures, 11% complained of severe headaches, and 1 patient experienced severe visual loss.
In 2003, Buccino et al found a good overall outcome in their reinvestigation of a series of 34 patients with confirmed cerebral venous thrombosis. However, 10 patients (30%) had episodic headaches, 3 patients (8.8%) had seizures, 4 patients (11.7%) had pyramidal signs, and 2 (5.9%) had visual deficits. Mild nonfluent aphasia was seen in 3 patients. Working memory deficit and depression of mood were seen in 6 patients (17.6%).
Race
No racial predilection has been observed.Sex
CVT is believed to be more common in women than men. In a series of 110 cases, Ameri and Bousser found a female-to-male ratio of 1.29:1 (Ameri, 1992).Age
In 1992, Ameri and Bousser reported a uniform age distribution in men with CVT, while 61% of women with CVT were aged 20-35 years. This may be related to pregnancy or the use of oral contraceptives.History
- Patients may present with headache. Although thunderclap headache usually indicates subarachnoid hemorrhage (SAH), it also may be seen in sinus thrombosis.
- SAH has been described as the presenting event with CVT. CVT should be considered in the workup of SAH, especially when the basilar cisterns are not involved (Oppenheim, 2005).
- Nausea and vomiting may be associated.
- Patients with lateral sinus thrombosis may present with a pseudotumor cerebri�like syndrome. Using a technique called auto-triggered ellipticcentric-ordered 3-dimensional gadolinium-enhanced MR venography, Farb et al found that 27 of 29 patients with idiopathic intracranial hypertension had bilateral sinovenous stenosis; this was seen in only 4 of 59 control subjects (Farb, 2003).
- Patients may have seizures that can be recurrent.
- Patients may have a decreased level of consciousness that progresses to coma.
- Focal neurological deficit may occur depending on the area involved.
. . . Continue to article and footnotes (PDF).
Dr. Alvin McElveen is a board certified neurologist who is also a Fellow with the American Academy of Neurology. He is also Certified in the medical subspecialty of Vasculary Neurology, MRI and CTscans by the American Society of Neuroimaging and the American Board of Independent Medical Examiners.
Dr. McElveen is recognized as one of the best doctors in the country by the Center for the Study of Services and is listed in "Who's Who in Medicine and Healthcare" 2000-2001. He founded Bradenton Neurology in 1979. He has been performing Independent Medical Examinations and serving as an expert witness for 12 years.
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