Motor Dysfunction of the Small Bowel and Colon in Patients with the Carcinoid Syndrome and Diarrhea

Diarrhea occurs in 80 percent of patients with the carcinoid syndrome 1 – 3 . Its pathophysiology is poorly understood, but it probably is multifactorial. A variety of tumor products, including serotonin, substance P, histamine, kallikrein, and prostaglandins, 4 , 5 can stimulate peristalsis, electromechanical activity, and tone in the intestine 6 – 10 . Malabsorption may result from intestinal resection, lymphangiectasia due to mesenteric fibrosis, bacterial overgrowth above a tumor partially obstructing the small bowel, or rapid intestinal transit 11 . Quantitative data on gut motor function in patients with the carcinoid syndrome are limited, but two patients were found to have abnormal motility of the . . .