Renal Concentrating Capacity Test by Desmopressin in Children: Intranasal or Intravenous Route?

Abstract

Intranasal administration of desmopressin (dDAVP) is frequently used to test renal concentrating capacity in children. However, the bioavailability of intranasal dDAVP is about 10% and may be modified by nasal congestion. The study aimed to compare the efficacy of intranasal dDAVP with an equivalent dose of intravenous dDAVP for a renal concentrating capacity test in children. We studied 18 children aged 12.6 ± 3.8 years weighing more than 20 kg in whom a dDAVP test was indicated as part of global renal function evaluation. Spray applicator (Minirin Spray) was used for intranasal administration (20-40 ug according to BW); the dose of intravenous dDAVP (Minirin IV) was reduced to 10% (2-4 ug according to BW). A randomized sequence was used for the first intranasal or intravenous dDAVP test; the second alternate test was repeated in the same children in a time interval ranging from 1 to 3 weeks. Osmolality of the urine (Uosm, mosm/kg) was determined before (TO), then 2 (T2) and 4 (T4) h after dDAVP administration. There was no significant difference in Uosm at TO (intranasal = 480 ± 212, intravenous = 443 ± 168 mosm/kg), T2 (604 ± 226 and 542 ± 173 mosm/kg, respectively), and T4 (657 ± 206 and 629 ± 190 mosm/kg, respectively). There was an obvious correlation between intranasal and intravenous Uosm at T4 (r² = 0.826; p = 0.001). Even if intravenous dDAVP is of theoretical interest, intranasal administration of dDAVP using a spray applicator can be considered as first-choice method for a renal concentrating capacity test in children weighing more than 20 kg.