Effects of restorative proctocolectomy on renal and adrenal function

PURPOSE: Restorative proctocolectomy is a standard procedure in the surgica l treatment of ulcerative colitis and familial adenomatous polyposis. The r adical removal of the colorectum with construction of an ileostomy often re sults in high stoma losses. These may lead to changes in the electrolyte an d acid-base balance and to alterations in renal and suprarenal gland functi on. METHODS: In this study 33 patients who received an ileoanal pouch befor e and after proctocolectomy were investigated at different time intervals f or electrolyte changes, alteration of the acid-base balance, kidney functio n, and hormonal changes of the supra-renal glands. Measurements were perfor med before proctocolectomy, ten days after proctocolectomy with ileal pouch -anal anastomosis under protective loop ileostomy, before ileostomy closure , and 6 to 12 months after ileostomy closure. Neither acute renal failure n or other vital complications were observed. RESULTS: Statistical analysis s howed a significant decrease of urine pH to 5.4 +/- 0.22 (before ileostomy closure) and metabolic acidosis (pH 7.32 +/- 0.04; base excess -1.3 +/- 5.6 (before ileostomy closure)). Likewise, we found a decrease in renal cleara nce to 86 ml/minute (before ileostomy closure) without signs of tubular dam age. The most important change during the phase with ileostomy was a functi onal secondary hyperaldosteronism with aldosterone levels of 63.2 +/- 70.8 ng/dl (before ileostomy closure). In comparison with preoperative levels, t here was a ten-fold increase in mineralocorticoid adrenal activity. Additio nally, during the period with protective ileostomy, the hepatic synthesis o f aldosterone-18-glucuronide was only slightly increased, and the cortisol/ cortisone ratio was extremely decreased. CONCLUSIONS: These results show t hat restorative proctocolectomy with ileal pouch-anal anastomosis and prote ctive loop ileostomy significantly influences fluid, electrolyte, and acid- base balance. Functional secondary hyperaldosteronism is of central importa nce for subsequent renal recompensation. Approximately one-half year after ileostomy closure, the endogenous hormones with mineralocorticoid effects r eturned to normal levels.