title: Monosymptomatic primary enuresis: differences between patients responding or not responding to oral desmopressin.
abstract: OBJECTIVE
  To evaluate the 24-h diuresis, urinary osmolality, plasma arginine vasopressin (AVP) and urinary prostaglandin E2 (PGE2) before and during desmopressin treatment in patients with monosymptomatic primary enuresis (MPE), and to investigate the possible depressor effect of desmopressin on the detrusor in such patients with urodynamically confirmed bladder instability.
  
  
  METHODS
  Seven healthy children (control group) and 11 consecutive patients with MPE (mean age 10.4 years, range 7-15) were assessed using laboratory tests, renal and bladder ultrasonography, and video-urodynamic investigations. A 24-h inpatient assessment with a controlled water intake of 20 mL/kg per day included determinations of diuresis, urinary osmolality, AVP and PGE2 in both normal children and those with MPE. After 30 days of treatment at optimal doses of desmopressin, all children were hospitalized and re-evaluated during desmopressin treatment; all completed 3 months of treatment at optimal doses. At the end of this period, patients whose symptoms improved by > or = 80% were defined as 'responders' while those in whom they did not were defined as 'non-responders'.
  
  
  RESULTS
  After treatment, six of the 11 patients with MPE were 'responders' and five 'non-responders'. Urodynamic evaluation showed bladder instability in seven of the 11 patients with MPE but in those with bladder dysfunction, urodynamic studies carried out during desmopressin treatment showed no changes in detrusor activity. There were significant differences in the morning values of AVP between normal children and responders (P < 0.03), and between responders and non-responders (P < 0.02); none of the non-responders had AVP levels of < 2.5 pg/mL, while none of the responders exceeded this value. At midnight, responders had the lowest mean AVP and non-responders the highest; this correlated with the highest PGE2 value in the nonresponders at 00.00-08.00 hours. Non-responders had an overnight mean PGE2 level greater than that in normal subjects or responders.
  
  
  CONCLUSIONS
  Polyuria occurred in all patients with MPE, independently of the response to desmopressin. Responders had the lowest AVP values over the 24 h; the morning AVP levels differentiated normal subjects from enuretic patients and responders from non-responders. In patients with MPE, clinically undetected bladder instability was unrelated to the results of treatment and there were no urodynamic changes during desmopressin treatment. The differences between enuretic patients suggested a different aetiology of MPE, probably related to an increase in PGE2 concentration and an antagonistic mechanism of action of AVP or desmopressin.
authors.affiliation: Unidad de Urología, Laboratorio Central, Hospital de Niños Ricardo Gutierrez, Buenos Aires, Argentina.
authors.forename: R
authors.initials: R
authors.lastname: Medel
authors.forename: S
authors.initials: S
authors.lastname: Dieguez
authors.forename: M
authors.initials: M
authors.lastname: Brindo
authors.forename: S
authors.initials: S
authors.lastname: Ayuso
authors.forename: C
authors.initials: C
authors.lastname: Canepa
authors.forename: A
authors.initials: A
authors.lastname: Ruarte
authors.forename: M L
authors.initials: ML
authors.lastname: Podesta
mesh_terms: D000284:Administration, Oral; D000293:Adolescent; D001127:Arginine Vasopressin / Q000097:blood; D002648:Child; D003894:Deamino Arginine Vasopressin / Q000008:administration & dosage*; D015232:Dinoprostone / Q000652:urine; D004775:Enuresis / Q000097:blood / Q000188:drug therapy* / Q000652:urine; D005260:Female; D006801:Humans; D008297:Male; D009994:Osmolar Concentration; D012008:Recurrence; D012076:Renal Agents / Q000008:administration & dosage*; D017211:Treatment Failure; D014554:Urination / Q000502:physiology; D014556:Urine / Q000502:physiology
chemical_list: D012076:Renal Agents; D001127:Arginine Vasopressin; D003894:Deamino Arginine Vasopressin; D015232:Dinoprostone