[Bladder replacement and continent diversion: what about metabolic complications?].

During the past several years there has been increasing interest in refunctionalizing patients who have undergone radical extirpative surgery for pelvic malignancies and patients with dysfunctional bladders. To accomplish this, intestinal segments have been successfully employed in a variety of configurations. Independent of their optimal urosurgical implementation these procedures are not without potential complications, a significant portion of which involve metabolic derangements. Besides first follow-up results of patients with bladder substitution or continent urinary diversion, analysis of experimental investigations and functionally comparable clinical conditions enables an insight into potential following physiopathological interrelationships. These concern, besides the problem of chronic metabolic acidosis, disorders of bile acid and vitamin B12 metabolism as well as the potential induction of a secondary hyperoxaluria with subsequent oxalate concrement diathesis. Furthermore, there may be a malabsorption of calcium and vitamin D with development of intestinal osteopathy due to the reduction of absorptive surface. Apart from these problems of enteral loss and deficiency manifestations, several case reports and investigations suggest that bone demineralization can occur as a consequence of chronic metabolic acidosis and patients are at risk of skeletal demineralization. The pathogenesis of this association has yet to be clarified. These physiopathological interrelationships must be considered in medical attendance of patients with intestinal substitute bladders and continent supravesical pouch systems over many years. As these procedures become more popular, it becomes important to identify any metabolic changes that may occur as their consequence.