Ischemic Stroke Secondary to Paradoxical Embolism Through a Pulmonary Arteriovenous Malformation: Case Report and Review of the Literature.

Paradoxical embolism due to isolated pulmonary arteriovenous malformation (AVM) is an uncommon cause of ischemic stroke, with the majority occurring in patients who have not yet been diagnosed with their malformation. We report a 32-year-old man who presented with an abrupt onset of right facial weakness and expressive aphasia. Brain magnetic resonance imaging revealed an acute infarct in the left middle cerebral artery territory and chronic infarcts in the bilateral cerebellar hemispheres. A cardioembolic mechanism was initially considered in the setting of perimyocarditis diagnosed a few months earlier. Transthoracic and transesophageal echocardiograms revealed high volume right to left shunting, but no septal defects. A pulmonary AVM was confirmed with computed tomography angiography and fistualization was successfully treated with embolization. This report highlights a case of undiagnosed pulmonary AVM leading to recurrent paradoxical emboli to the brain. We review the epidemiology, pathophysiology, and management of pulmonary AVMs in relation to stroke risk.