Intranasal DDAVP-test in the study of renal concentrating capacity in children with recurrent urinary tract infections.

Intranasal administration of DDAVP (1-deamino-8-D-arginine vasopressin), a synthetic analogue of vasopressin, followed by measurement of urine osmolaity 6 h afterwards, represents a convenient, reliable and simple method for the estimation of renal concentrating capacity in children. The DDAVP-test is as accurate and reproducible as the water deprivation test, irrespective of the degree of concentrating capacity. Mean urine osmolality after DDAVP in children without renal disease was found to be 984 +/- 218 mosmol/kg water (m +/- 2 SD). In children with recurrent pyelonephritis, urine osmolality after DDAVP was decreased. The values were significantly lower with bilateral changes than with unilateral changes of chronic pyelonephritis in the i.v. urograms. In chronic pyelonephritis the concentrating capacity appears to be earlier impaired than other parameters of renal function.