Colonic dysfunction during shigellosis.

To study the pathogenesis of shigella diarrhea, we evaluated 11 patients for colonic fluid and electrolyte flux. Methods used were subtraction of the fecal flow rate from the ileocecal flow rate and colonoscopic perfusion of the colon. The mean ileocecal flow rate was 0.57 ml/min compared with a mean fecal flow rate of 0.48 ml/min, and the mean of the differences showed a slight net colonic water absorption of +0.09 ml/min. With use of perfusion, these patients showed an overall mean of slight net fluid secretion by the colon of -0.04 ml/min. Seven patients restudied during convalescence showed a mean net rate of colonic water absorption of +0.65 ml/min, which was significantly greater than in the acute phase (P less than .05), and a mean ileocecal flow rate of 0.56 ml/min. Ion transport by the colon during acute shigellosis showed net secretion of K+, which changed to net absorption in convalescence (P less than .05), and a decreased absorption of Cl-, which improved in convalescence (P less than .05). Patients with extensive colitis showed more impairment of net water absorption by the colon than did patients with colitis limited to the rectosigmoid colon. These findings demonstrate that shigella diarrhea results from colonic dysfunction, without evidence of increased small intestinal flow rate, and this colonic dysfunction consists of diminished net absorption of water and Cl- and increased secretion of K+.