A 45-year-old woman with flushing and diarrhea develops edema of the legs and a diastolic murmur at the left lower sternal border. Echocardiography shows thickened, shortened tricuspid and pulmonary valve leaflets with restricted motion. The pathogenesis involves:
- A Serotonin reaching the right-sided valves before hepatic metabolism ✓
- B Immune complex deposition on the pulmonary valve
- C Embolization of tumor fragments from a bronchial carcinoid
- D Anorexigen drug-induced valvular fibrosis
Correct answer: A. Serotonin reaching the right-sided valves before hepatic metabolism
Explanation
Carcinoid heart disease results when vasoactive substances, chiefly serotonin, released from a metastatic neuroendocrine tumor reach the right heart directly through the venous circulation. In patients without hepatic metastases the liver metabolizes serotonin and the heart is spared. Left-sided valves are protected because serotonin is degraded in the lungs, so left-sided involvement occurs only with a patent foramen ovale or primary bronchial carcinoid. The plaques are fibrous, not immune complexes or tumor deposits.
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.