Water and electrolyte balance after ileal J pouch-anal anastomosis in ulcerative colitis and familial adenomatous polyposis

The water and electrolyte balance was studied in 31 patients with ulcerative colitis (UC) and 22 with familial adenomatous polyposis (FAP) who underwent staged surgery involving colectomy and ileal J pouch-anal anastomosis (IAA), preoperatively, after terminal ileostomy, after high ileostomy, and after ileostomy closure. Serum electrolytes did not differ between each surgical stage. After terminal or high ileostomy, daily urine volume and urinary sodium loss was significantly lower, and daily fecal weight and fecal sodium loss was significantly higher than preoperatively. After ileostomy closure, urinary and fecal sodium loss became closer to preoperative value. Daily urinary potassium loss was significantly higher and fecal loss was lower after terminal and high ileostomy than preoperatively and did not show a significant change after ileostomy closure. The urinary sodium to potassium ratio after ileostomy closure was lower than preoperatively, but was higher than that after terminal and high ileostomy. Plasma aldosterone and renin levels were only significantly increased after high ileostomy. These findings indicate that high or terminal ileostomy caused chronic dehydration, which was compensated for by activation of the renin-aldosterone axis, while the water and electrolyte balance became closer to normal after ileostomy closure following ileoanal anastomosis.