METABOLIC AND NUTRITIONAL COMPLICATIONS

Abstract

Metabolic and nutritional complications of urinary diversion through bowel or stomach segments are common, but fortunately, not often severe. When metabolic abnormalities are problematic, deterioration or baseline insufficiency in renal function is the most likely cause. Deterioration is most commonly associated with obstruction or infection. The urologist should be acutely aware of the potential for metabolic derangements when the prediversion creatinine is greater than 2.0 mg/dL. In this situation, the urologist should employ the basic principles in this article when planning the procedure in order to minimize metabolic complications and morbidities. In the setting of significant renal insufficiency, a short colon or ileal conduit would likely be superior to an ileal or colonic neobladder, or a diversion, incorporating a large gastric segment. Furthermore, in the absence of symptomatic metabolic abnormalities, we advocate treatment of minor laboratory abnormalities, particularly acidosis, to reduce the incidence of metabolic bone disease. Nutritional and gastrointestinal complications are treated on an "as needed" basis, with the exception of metabolic bone disease, which we would hope to prevent with alkalinization and Vitamin C supplementation. Some of the nutritional and gastrointestinal complications are best avoided by leaving the ileocecal valve intact, or by minimizing the use of certain segments. Some evidence exists that over time, histologic changes in the epithelium of diversion segments may impair absorption and contribute to greater resistance against metabolic derangements. Whether the changes truly reduce the incidence of metabolic abnormalities remains to be studied. The ideal, complication-free, diversion with universal application does not exist; however, the urologist must strive to select an option that will provide a functional result for the patient with minimal associated morbidity.