A 55-year-old woman has episodic flushing, diarrhoea, and right-sided heart murmur. 24-hour urine 5-HIAA is 48 mg (normal <8 mg). CT abdomen shows a 1.5 cm ileal mass with multiple liver metastases. The PRIMARY mechanism of carcinoid heart disease and the PREFERRED initial treatment for symptomatic tumour control is:
- A Dopamine excess causing left-sided valvular disease; bromocriptine
- B Bradykinin causing left-sided mitral stenosis; ACE inhibitor
- C VIP excess causing tricuspid regurgitation; propranolol
- D Serotonin (5-HT) causing fibrous endocardial plaques predominantly on right-sided valves (as serotonin is inactivated in the lungs); octreotide LAR (somatostatin analogue) ✓
Explanation
Carcinoid heart disease (Hedinger syndrome) is caused by serotonin (5-HT) and other vasoactive mediators from hepatic metastases reaching the right heart directly via hepatic veins into the inferior vena cava. Serotonin induces fibrous plaque formation (carcinoid plaques) on the endocardium of the right-sided valves (tricuspid and pulmonary valves), causing tricuspid regurgitation and pulmonary stenosis. Left-sided involvement is rare because serotonin is metabolised by pulmonary endothelium. First-line symptom control is octreotide LAR (or lanreotide) — somatostatin analogues that reduce hormone secretion and slow tumour growth (PROMID and CLARINET trials).
Reference: Harrison's Principles of Internal Medicine, 21st ed.
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Written and medically reviewed by the StethoPrep medical team.