Young stroke due to pulmonary arteriovenous malformation.

Young patients presenting with cryptogenic stroke should be investigated for cardiac and extra-cardiac sources of emboli. We present a patient who was investigated for a cardiac source of emboli, following multiple ischaemic strokes and migraine with aura over a period of 17 years. The events were initially thought to be related to a patent foramen ovale (PFO) on bubble contrast echocardiography, however, due to an unusual flow pattern to the left heart, she underwent a CT angiogram to exclude intrapulmonary shunting. This confirmed the presence of a moderate sized congenital pulmonary arteriovenous fistula in the left lung. Transcatheter occlusion of the vascular malformation has resolution of her symptoms. Bubble contrast echocardiography is routinely used to diagnose a PFO in these cases, but extreme caution is required during the procedure to differentiate the pattern of flow seen in patients with a pulmonary arteriovenous malformation.