title: The efficacy of DDAVP is related to the circadian rhythm of urine output in patients with persisting nocturnal enuresis.
abstract: OBJECTIVE
  Desmopressin may be a useful treatment in some, but not all, patients with nocturnal enuresis. We have evaluated a relation between nocturnal urine output in patients with primary monosymptomatic nocturnal enuresis and the treatment response to synthetic vasopressin.
  
  
  METHODS
  Adolescent or adult enuretics and normal subjects were enrolled in the study and admitted to hospital for a 24 hour investigation of the diurnal variation in urine output, plasma vasopressin (AVP) and plasma atrial natriuretic peptide (ANP). The enuretics were characterized prior to investigation as either 1-desamino-8-D-arginine vasopressin (DDAVP) responders or non-responders. During admission the fluid intake was restricted to 25 ml/kg per day.
  
  
  METHODS
  Twenty-four patients (15-37 years) with primary monosymptomatic nocturnal enuresis and 9 normal subjects (24-31 years).
  
  
  METHODS
  Circulating levels of AVP, ANP, plasma electrolytes and plasma osmolality were measured (1400, 2000, 2300, 0200, 0500 and 0800 hours) together with urine volume, urine osmolality and urine electrolytes during daytime and nighttime. Tubular reabsorptive capacity for water, osmoles and creatinine were assessed as well as urinary and fractional excretion rates of sodium and potassium.
  
  
  RESULTS
  Controls and DDAVP non-responders had a significant decrease in urine output at night concomitant with a significant plasma AVP amplitude in peak/nadir values although both groups lacked a significant nocturnal increase in AVP. In contrast, in DDAVP responders there was no circadian variation in urine output and thus a nocturnal polyuria together with no oscillation in plasma AVP. The DDAVP responding group had a nocturnal urine production significantly larger than the two other groups. However, the mean 24 hour AVP levels were similar in all groups. The excessive urine production at night in DDAVP responders was accompanied by nocturnal natriuresis due to an increased fractional excretion of sodium. In contrast, nocturnal antidiuresis in controls and DDAVP non-responding enuretics coincided with diminished sodium excretion. Average ANP levels were elevated in both enuretic groups compared to normals, whereas a circadian variation was detected only in the latter.
  
  
  CONCLUSIONS
  It is concluded that DDAVP responsiveness is linked to the nocturnal urine production and that no pathophysiological role can be ascribed to AVP or ANP in DDAVP refractory adolescent and adult enuretics. Moreover, it is suggested that an abnormal tubular handling of sodium may contribute to the nocturnal polyuria seen in DDAVP responders.
authors: International Enuresis Research Centre, University of Aarhus, Denmark.
authors: J M
authors: JM
authors: Hunsballe
authors: T K
authors: TK
authors: Hansen
authors: S
authors: S
authors: Rittig
authors: E B
authors: EB
authors: Pedersen
authors: J C
authors: JC
authors: Djurhuus
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D009320:Atrial Natriuretic Factor / Q000097:blood; D016022:Case-Control Studies; D002940:Circadian Rhythm; D003894:Deamino Arginine Vasopressin / Q000097:blood / Q000627:therapeutic use*; D004775:Enuresis / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D009994:Osmolar Concentration; D012076:Renal Agents / Q000097:blood / Q000627:therapeutic use*; D012964:Sodium / Q000652:urine; D016896:Treatment Outcome; D014554:Urination
chemical_list: D012076:Renal Agents; D009320:Atrial Natriuretic Factor; D012964:Sodium; D003894:Deamino Arginine Vasopressin