POTENTIALLY PROTHROMBOTIC ABNORMALITIES OF COAGULATION IN BENIGN INTRACRANIAL HYPERTENSION

Objective-Benign intracranial hypertension (BIH) may be caused by intr acranial venous sinus thrombosis. Cerebral angiograms may, however, be normal in patients with BIH that are associated with conditions with an increased risk of venous thrombosis. This raises the possibility th at unrecognised non-occlusive venous thrombus might impede CSF drainag e. This study therefore examined the strength of the association betwe en risk factors for thrombosis and BIH. Methods-The incidence of proth rombotic abnormalities among a mixed prospectively and retrospectively investigated cohort of 38 patients with BIH, was compared with health y obese subjects, and patients with other neurological diseases. Proth rombotic abnormalities investigated included anticardiolipin antibodie s, lupus anticoagulant, antithrombin III, proteins C and S, plasma fib rinogen, kaolin cephalin clotting time, prothrombin time, and full blo od counts. Results-Evidence for the presence of an antiphospholipid an tibody was found in 32% of cases. Cases of familial deficiency of anti thrombin III, thrombocytosis, and polycythaemia were also noted. Addit ionally, an increased concentration of plasma fibrinogen was found in 26%. A coagulation abnormality was more often detectable in those subj ects with normal or low body mass index and in those tested within six months of onset. Conclusion-There is a thrombotic pathogenesis in som e cases of BIH.