Indicanuria after Gastric Surgery
The level of indican excreted in the urine per 24 hours has been measured in 127 subjects following gastric surgery (18 Billroth 1 type partial gastrectomies, 63 Polya type partial gastrectomies, and 46 gastroenterostomies). These results have been compared with 141 normal control subjects. In the control group the level of dietary tryptophane intake correlated directly with the level of indicanuria, which may account for the wide variation in normal values reported in the literature.

The dietary intake of tryptophane was significantly lower in the post-gastric-surgery subjects than in the matched controls. This may be a factor in the severe protein depletion reported following partial gastrectomy. Twenty-nine (23 per cent) of our post-gastric-surgery group had elevated indican levels; all had had either Polya partial gastrectomy, or gastroenterostomy, both of which entail the creation of a ‘blind’ loop liable to bacterial colonization. By contrast there was no difference in the Biflroth 1 subjects when compared with the control group.

The level of indicanuria and the E. coil population of the small intestine have been shown to be related in 10 patients following gastric surgery. The metabolic significance of this was supported by a faecal-fat excretion in 18 subjects significantly related to indican excretion; and by the relation of post-operative weight loss to the levels of indicanuria in the whole group. It is suggested that bacterial colonization of the afferent loop following Polya gastrectomies and gastroenterostomies is underestimated as a cause of steatorrhoea and post-operative weight loss.

No relationship was found between indican excretion and serum vitamin B12' serum iron, or the degree of post-operative anaemia. The reasons for these findings are discussed.

The level of indican excreted in the urine following gastric operations is proportional to the degree of bacterial colonization of the upper small intestine. It may therefore indicate when further metabolic complications are to be expected.