ABSTRACT

A 32-year-old woman is admitted with severe headache and vomiting that has gradually been getting worse over the previous week. She has no significant past medical history and she is otherwise fit and well. A magnetic resonance imaging (MRI) scan shows cerebral venous sinus thrombosis. There is no family history of thrombosis and there are no obvious provoking factors. She completes 6 months of anti-coagulation with warfarin. She is now asymptomatic and a repeat MRI scan shows residual thrombus although the overall size has reduced. A thrombophilia screen is carried out and shows a weakly positive dilute Russell viper venom time (DRVVT). Three months later, the DRVVT is still weakly positive and tests for anti-cardiolipin and anti-β2 glycoprotein 1 antibodies are negative.