A 62-year-old man with an ileal neuroendocrine tumour and multiple liver metastases presents with episodic flushing and watery diarrhoea. Echocardiography shows thickening of endocardial plaques on one side of the heart. Which valves are characteristically involved?

• A Mitral and aortic valves
• B Aortic and pulmonary valves
• C All four valves are involved with equal frequency
• D Tricuspid and pulmonary valves ✓

Explanation

Carcinoid heart disease affects the right side of the heart because serotonin released into the hepatic veins reaches the right atrium directly and produces fibrous endocardial plaques, classically causing tricuspid regurgitation and pulmonary stenosis. The left-sided valves are protected because monoamine oxidase in the pulmonary endothelium inactivates serotonin during passage through the lungs. Left-sided disease occurs mainly with bronchial carcinoid or a patent foramen ovale, not with an ileal primary.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.