Summary
To evaluate the association between coagulation defects and cerebral venous thrombosis,
a case-control study was conducted in 25 patients who had no autoimmune, neoplastic
or infectious disease and 75 healthy individuals. There were no patients with deficiency
of protein C or protein S. Four had resistance to activated protein C (APC) and one
had APC resistance associated with antithrombin deficiency. APC resistance was investigated
by DNA analysis, and diagnosed by the presence of a point mutation in the factor V
gene, which predicts replacement of Arg506 with Gin at one of the two APC cleavage sites in activated factor V. The prevalence
of APC resistance was 20% in patients and 2.7% in controls. This difference was statistically
significant (p = 0.01) and the odds ratio was 9.1. A circumstantial factor predisposing
to cerebral venous thrombosis (such as oral contraceptive intake, pregnancy, puerperium,
trauma or prolonged immobilization) was reported in 72% of cases. In conclusion, APC
resistance is the most frequent coagulation abnormality associated with cerebral venous
thrombosis.