Thrombosis of the draining vein causes intracranial haemorrhage in the natural history of brain arteriovenous malformation: case report.

Rupture of arteriovenous malformations (AVM) may be caused by venous outflow restriction, but there is no radiographic evidence of this. We report a case showing only a venous thrombus preceding intracranial haemorrhage from AVM. This is the first evidence that venous thrombus results in AVM rupture in its natural history.