Pulmonary arteriovenous malformation: a rare, treatable cause of stroke in young adults.

Pulmonary arteriovenous malformation (PAVM) predisposes affected patients to a significantly increased risk of stroke. Most commonly, PAVM is seen in patients with hereditary haemorrhagic telangiectasia (HHT), an inherited disorder that can be difficult to diagnose in young people because of variable age-related penetrance. As such, stroke in the young adult may be the presenting feature of underlying PAVM in a previously undiagnosed patient. The importance of considering this diagnosis in the evaluation of young adults with cryptogenic stroke is underscored by the availability of both sensitive screening and effective treatment for PAVM, from which this at-risk population can greatly benefit.