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6.7:
Venous thrombosis Venous thrombosis as the cause of headache has received relatively little attention. Classic presentation of cortical vein thrombosis is with seizures and headache. There may be neurologic deficits depending upon what venous areas are affected. For example, with sagittal sinus venous thrombosis there may be an initial presentation of weakness in the legs bilaterally, obtundation as intracranial pressure rises, and even papilledema. Therapy in venous thrombosis is changing and many now advocate anticoagulation. Considerable controversies still exist, however, as to whether to anticoagulate in the face of a significant hemorrhagic infarction. The causes of venous thrombosis predisposing conditions have been divided into local and general categories by Bousser and Barnett (1988). Bousser had divided the causes into local and general. Among the local causes are direct septic trauma, intracranial infection, head injury, and tumors. Among the general causes are bacterial septicemia, tuberculosis, fungal infections, post-partum state, oral contraceptives, and coagulation disorders. Headache was present in 80 percent of 76 patients. Papilledema was present in 50 percent, and focal motor or sensory defects in 35 percent, and seizures in 29 percent. The classical picture in superior sagittal sinus thrombosis is bilateral or alternating deficits particularly in the lower limbs accompanied by seizures. Some patients present with isolated intracranial hypertension with headache, papilledema, and sixth nerve palsy mimicking benign intracranial hypertension. This was present in 38 percent of Bousser and Barnett’s patients. A cavernous sinus thrombosis syndrome including chemosis, proptosis, and painful ophthalmoplegia, initially unilateral but frequently becoming bilateral, is a classic distinctive clinical picture. Severe complications can occur such as extension to other sinuses and stenosis or thrombosis of the intracavernous portion of the internal carotid artery. However, cavernous sinus thrombosis is not always acute and even can take a more indolent form sometimes due to inadequate antibiotic therapy present with an isolated abducens palsy with only mild chemosis and proptosis leading to great diagnostic difficulty (Dinubile, 1988). Venous thrombosis can present with isolated headache simulating a post-lumbar puncture headache. The diagnosis of cerebral venous thrombosis may be suspected on the basis of the clinical presentation such as headaches and seizures. CT scanning may show a partially hemorrhagic infarction. Angiographic diagnosis of isolated cortical vein thrombosis is extremely difficult. A CT scan sign, the empty delta sign, (Buonanno et al, 1978) is the most frequent direct sign of sagittal sinus thrombosis present in approximately 30 percent of cases. It appears after contrast injection and reflects the opacification of collateral veins in this superior sagittal sinus wall contrasting with the non-injection of the clot inside the sinus. MRI offers major advantages for the evaluation of patients suspected of having cerebral venous thrombosis because of its sensitivity to blood flow and the ability to visualize the thrombus itself. These changes are described elsewhere in detail (Bousser and Barnett, 1988). |