A 24-year-old man with chest pain, hemoptysis, and hypoxia.

The diagnosis of pulmonary arteriovenous malformations in patients remains a diagnostic challenge to the emergency physician. Pulmonary arteriovenous malformations are abnormal direct connections that shunt unoxygenated blood from pulmonary arteries to pulmonary veins, resulting in hypoxia. They represent a rare clinical entity and are usually associated with hereditary hemorrhagic telangiectasia. We report a case of a young man who presented to the emergency department with an acute onset of right-sided chest pain, and vital signs and laboratory findings that did not clinically correlate with his history or physical examination. To our knowledge, there are no case reports of pulmonary arteriovenous malformations described in the emergency medicine literature.