Summary

Dural arteriovenous fistula (DAVF) is a rare complication of cerebral venous sinus thrombosis (CVST). DAVFs develop as a result of direct arterial to venous sinus communications evolving in response to an occluded sinus. The authors present a patient with Down’s syndrome who developed progressive, uncontrolled seizures and chronic CVST secondary to factor V Leiden deficiency. Brain MRI and computerised tomographic venography revealed a complex secondary DAVF, which once embolised resulted in a dramatic reduction in seizures and improvement in the clinical state. DAVFs should be considered as a potential complication in patients with persistent features of CVST.