A Rare Incidental Discovery of an Intrapulmonary Shunt in a Young Man: A Case Report.

An intrapulmonary shunt (IPS) occurs when blood bypasses oxygenation in the lungs, flowing directly from the right side of the heart to the left side without undergoing gas exchange. This condition is distinct from an intracardiac shunt, which involves an abnormal connection between the heart chambers or vessels, allowing atypical blood flow. In this report, we present the case of a 21-year-old man with a one-year history of persistent cough, nocturnal chest pain, nasal congestion with shortness of breath, and generalized abdominal pain. In the emergency department, his vital signs and physical examination were unremarkable. Electrocardiography (EKG) revealed sinus bradycardia with right-axis deviation and incomplete right bundle branch block pattern. Chest X-ray and routine laboratory investigations were normal. The patient was referred to cardiology for further evaluation of shortness of breath. A transthoracic echocardiogram (TTE) with a bubble study demonstrated a normal ejection fraction of 63% with no regional wall motion abnormalities. Agitated saline injected via the left antecubital vein revealed no bubbles in the left atrium during the first six cardiac cycles. However, after six cycles, a small number of bubbles appeared in the left atrium and left ventricle, indicative of an IPS. In this case report, we highlight a unique incidental finding of an IPS in a young man, emphasizing the importance of bubble study timing in distinguishing IPS from intracardiac shunts.