Desmopressin resistant nocturnal polyuria secondary to increased nocturnal osmotic excretion.
OBJECTIVE
We investigated the role of increased solute excretion in children with desmopressin resistant nocturnal enuresis and nocturnal polyuria.


METHODS
A total of 42 children with monosymptomatic nocturnal enuresis and significant nocturnal polyuria with high nocturnal urinary osmolality (more than 850 mmol/l) were not responding to desmopressin. A 24-hour urinary concentration profile was obtained with measurement of urine volume, osmolality, osmotic excretion and creatinine. The control group consisted of 100 children without enuresis.


RESULTS
Based on osmotic excretion patients were classified into 3 groups. Group 1 had 24-hour increased osmotic excretion, most likely secondary to a high renal osmotic load. This was probably diet related since 11 of these 12 patients were obese. Group 2 had increased osmotic excretion in the evening and night, probably due to a high renal osmotic load caused by the diet characteristics of the evening meal. Group 3 had deficient osmotic excretion during the day, secondary to extremely low fluid intake to compensate for small bladder capacity.


CONCLUSIONS
Nocturnal polyuria with high urinary osmolality in our patients with desmopressin resistant monosymptomatic nocturnal enuresis is related to abnormal increased osmotic excretion. This may be explained by their fluid and diet habits, eg daytime fluid restriction, and high protein and salt intake.
Dehoorne
Jo L
JL
Pediatric Nephrology and Pediatric Urology Department, University Hospital Ghent, Belgium.
Raes
Ann M
AM
van Laecke
Erik
E
Hoebeke
Piet
P
Vande Walle
Johan G
JG
D000293:Adolescent; D050034:Antidiuretic Agents / Q000627:therapeutic use*; D002648:Child; D002940:Circadian Rhythm; D003894:Deamino Arginine Vasopressin / Q000627:therapeutic use*; D004351:Drug Resistance; D005260:Female; D006801:Humans; D008297:Male; D009995:Osmosis; D011141:Polyuria / Q000188:drug therapy* / Q000378:metabolism / Q000503:physiopathology*; D012189:Retrospective Studies; D014554:Urination; D014556:Urine
D050034:Antidiuretic Agents; D003894:Deamino Arginine Vasopressin