Disaccharidase levels in the small intestine in patients with diarrhoea following vagotomy and pyloroplasty.

Diarrhoea is a common sequel to vagotomy and pyloroplasty but its cause is unknown. One of our patients who developed this complication had an abnormal lactose barium meal and responded well to a lactose-free diet. This led us to make a systematic study of disaccharidase activity in the small intestine in patients with diarrhoea following vagotomy and pyloroplasty. The small-intestinal disaccharidases have been estimated in jejunal biopsy specimens taken from 23 patients suffering from persistent diarrhoea, either continuous or episodic, after vagotomy and pyloroplasty. The disaccharidase values were normal in all but one of these patients. This patient showed hypolactasia but the sucrase and maltase levels were normal. The jejunal biopsy specimen taken from this patient showed a convoluted pattern under the dissecting microscope and severe partial villous atrophy under the light microscope. A repeat jejunal biopsy taken 20 cm beyond the duodeno-jejunal flexure showed similar appearances and also had a low level of lactase. However, two lactose tolerance tests and a lactose barium meal yielded normal results, suggesting that the low level of lactase in the upper jejunum was not a limiting factor in lactose absorption. The finding of one example of a low lactase level among 23 postvagotomy patients corresponds with what is being found in a study of normal subjects at present in progress. In effect, almost all patients with persistent diarrhoea after vagotomy and pyloroplasty have normal small-intestinal disaccharidase activity.