Paradoxical Brain Embolism Caused by Isolated Pulmonary Arteriovenous Fistula Successfully Treated with Recombinant Tissue Plasminogen Activator

Pulmonary arteriovenous fistula (PAVF), a vessel malformation connecting the pulmonary circulation to the systemic circulation while bypassing the pulmonary capillaries, can cause paradoxical cerebral infarction. It is often associated with hereditary hemorrhagic telangiectasia (HHT), a genetic disease characterized by multiple dermal, mucosal, and visceral telangiectasia causing recurrent bleeding. Paradoxical cerebral embolism caused by PAVF without HHT is rare. Here, we report a patient with isolated PAVF who experienced an ischemic stroke caused by a paradoxical embolism from deep venous thrombosis; the patient was successfully treated with recombinant tissue plasminogen activator. She presented with a decrease in arterial oxygen saturation to 91%, and lung disease was suspected. A PAVF was subsequently found in the right S6 region using contrast computed tomography. Interventional radiologists successfully occluded the shunt using 6 microcoils. PAVF should be considered when determining the pathogenesis of cerebral ischemia in patients with hypoxia, which can be the only symptom of PAVF.