Vitamin B-12 metabolism after urinary diversion with a Kock ileal reservoir

Objective: To elucidate the influence of construction of a Kock reservoir f or urinary diversion using 70 cm of the distal ileum ZD on vitamin B-12 met abolism. Material and Methods: Blood samples for determination of cobalamin concentr ations were drawn up to 18 years after construction of a Kock reservoir in 97 patients. Preoperative values were obtained in 20 of these patients. Pre - and postoperative Schilling tests and analyses of methylmalonic acid and homocysteine concentrations were performed in subgroups. Results: The operation did not induce a significant decrease in cobalamin u ptake as reflected in the pre- and postoperatively performed Schilling test s. No significant decline in cobalamin concentration postoperatively was no ted. The value of analysis of methylmalonic acid and homocysteine concentra tions in finding patients with cobalamin deficiency is limited by the fact that kidney function influences the results. Ten per cent of the patients d id develop true cobalamin deficiency. A postoperative vitamin B-12 value be low 200 pmol/l indicates a 50% risk of later cobalamin deficiency. Conclusions: The construction of a Kock reservoir does not per se cause cob alamin deficiency. Substitution should be instituted at a postoperative con centration below 200 pmol/l.