Right and Left-sided Valve Disease: A Case of Subclinical Intrapulmonary Shunt in an Adult with Malignant Carcinoid

Abstract

Carcinoid tumors are highly differentiated neuroendocrine tumors (NET) that most commonly
originate from the gastrointestinal tract. Liver metastases bypass first-pass metabolism and liberate
vasoactive hormones into systemic circulation, causing flushing and diarrhea. Prolonged levels
of circulating serotonin may adversely affect the heart by creating fibrotic endocardial deposits
on native valves. The remaining serotonin is metabolized in the pulmonary circuit that leads to
pathognomonic valvular disease isolated to the right side of the heart. We present a case of an adult
male with known carcinoid syndrome who presented with involvement of right, as well as left-sided
valves. He was found to have an intrapulmonary shunt on transesophageal echocardiogram (TEE)
with bubble study. Intrapulmonary shunt should be considered, in conjunction with right-to-left
shunt, lung involvement, and high levels of serotonin, for carcinoid patients with right and left-sided
valve disease.