Acid-Base Balance after Continent Urinary Diversion in Childhood – Risk of Imbalance Despite Medication

Purpose Continent urinary-intestinal diversion can lead to alterations of the acid-base balance, acutely and chronically, the latter possibly causing bone demineralization. Annual check-ups have therefore been recommended for decades. Material and Methods At our institution, 89 children underwent continent urinary diversion by ileocecal pouch or bladder substitution between 1984 and 2006. In 58 of these patients (age 3-17 y., median 13.9 y.), we performed a minimum of 3 (range 3-23, median 6.2) consecutive annual blood-gas analyses over a follow-up period of up to 23 years (median 11.0) after surgery. At a base excess (BE) (as marker of the acid-base-balance) value below -2.5 mmol/l, treatment was initiated. Results Of 58 patients, 17 (29%) constantly presented BE values above -2,5 mmol/l and therefore remained without medication. The majority of patients (n=41, 71%) was in need of continuous alkali supplementation. The BE values of the untreated patients showed a mild undulation within 2,5 and - 2,5 mmol/l over the years, whereas those under medication often presented peaks and troughs between 8 and -10 mmol/l. In those patients the medication was adjusted. Conclusions After continent urinary diversion by ileocecal pouch/bladder substitution in childhood, permanent alkali supplementation is necessary in the majority of the cases (71%). Those undergoing medication appear to be at greater risk for metabolic disturbances despite treatment. Therefore this group might carry a greater risk for later bone demineralization, and therefore needs a more frequent surveillance and adjustment of medication than previously thought.