Abstract
Congenital portosystemic shunts are rare vascular malformations in which portal venous blood from the intestines and spleen bypasses the liver and diverts directly into the systemic circulation through abnormal vessels. We report a case of a 4-year-old girl with heterotaxy syndrome, polysplenia, and situs inversus presenting with persistent hypoxemia who was found to have pulmonary arteriovenous malformations (PAVMs) and hypoxemia secondary to a congenital portosystemic shunt. Management of this patient's PAVMs involved endovascular occlusion of the portosystemic shunt with subsequent resolution of hypoxemia. PAVMs secondary to extrahepatic portosystemic shunt should be explored as a cause of progressive cyanosis in children with heterotaxy, polysplenia, and interrupted inferior vena cava with azygous continuation.