Oneliner_1377

OneLiner

Patient presents with diarrhea, a heart murmur, and valvular disease. Testing reveals the heart murmur is secondary to a neoplasm. This should raise suspicions for serotonin syndrome, secondary to a carcinoid tumor. Serotonin is secreted by carcinoid tumors, and causes symptoms of flushing, watery diarrhea, and right-sided valvular dysfunction.5-Hydroxyindoleacetic acid (5-HIAA) is a metabolite of serotonin that can be measured in a 24-hour urine collection. Suspect intravenous drug use or carcinoid syndrome when there is any pathology exclusively involving right-sided valves. Serotonin is metabolized in the lung vasculature, leaving left-sided valves unaffected.