Abstract
A diabetic patient (35 years old, male) complicated with acromegaly showed continuous diarrhea lasting for more than 1 year. He had severe diabetes and his blood sugar levels remained unstable despite insulin therapy. The diarrhea persisted after pituitary extirpation. Daily fecal fat excretion reached 28 g but he revealed no symptoms of malnutrition except for slight hypocholesterolemia. His exocrine pancreatic function and plasma VIP levels were normal.
The gastric emptying rate (acetaminophen absorption method) and transit in the upper digestive tract (lactulose-breath hydrogen method) were markedly accelerated. A shortening of the transit time in the total digestive tract (single stool-marker method) was also noted. Plasma motilin levels measured serially during fasting were strikingly elevated and showed fluctuations. The motilin levels tended to decrease after test meal ingestion.
Although the precise etiology of the diarrhea in the present case could not be elucidated, its mechanism appeared to be related to the marked increase in motility of the upper digestive tract. The increase in both gastrointestinal motility and plasma motilin was unusual. Its was not found in diabetic patients complicated with neuropathy and gastrointestinal dysfunction. Thus, the increased gastrointestinal motility probably causing diarrhea in the present patient may be based on the elevated motilin level or vice versa.
