title: Fluid control in elderly patients with nocturia.
abstract: OBJECTIVE
  To investigate the pathophysiology of nocturnal polyuria associated with aging.
  
  
  METHODS
  Fifty patients (mean age 67.7 years, range 50-87) with nocturia were recruited for this prospective study. Patients were classified into nocturnal polyuria (NP) and non-nocturnal polyuria (non-NP) groups based on records of their frequency-volume charts. A hypertonic saline infusion test was carried out to evaluate individual osmotic and volume control.
  
  
  RESULTS
  In the NP group, there was a significantly increased nocturnal diuretic rate compared with the daytime diuretic rate. In the non-NP group, there was a significantly decreased nocturnal diuretic rate compared with the daytime rate. There was also a positive correlation between systolic blood pressure and nocturnal diuretic rate, and a negative correlation between systolic blood pressure and daytime diuretic rate in those with NP, but no correlation in those without NP. Thus, a close relationship between diuretic rates and systolic blood pressure was seen in NP patients. Moreover, a slight overall shift upward from the physiological range of plasma osmolality relative to arginine vasopressin after hypertonic saline loading was seen in those with NP compared with those without. An altered circadian rhythm was also seen in diurnal plasma arginine vasopressin levels in patients with and without NP.
  
  
  CONCLUSIONS
  Patients with nocturnal polyuria are likely to have a more hypervolemic or vasoconstrictive condition. It is considered that non-osmotic control takes on a greater meaning in patients with nocturnal polyuria, though osmotic control contributes less to diuresis within the physiological plasma osmolality range with aging.
authors.affiliation: Department of Urology, Uda City Hospital, Uda, Nara, Japan. osnatsume@hotmail.com
authors.forename: Osamu
authors.initials: O
authors.lastname: Natsume
authors.forename: Yoshiteru
authors.initials: Y
authors.lastname: Kaneko
authors.forename: Akihide
authors.initials: A
authors.lastname: Hirayama
authors.forename: Kiyohide
authors.initials: K
authors.lastname: Fujimoto
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Hirao
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001127:Arginine Vasopressin / Q000097:blood*; D016022:Case-Control Studies; D002940:Circadian Rhythm; D005260:Female; D006417:Hematuria / Q000175:diagnosis / Q000652:urine; D006801:Humans; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D053158:Nocturia / Q000175:diagnosis* / Q000453:epidemiology; D009994:Osmolar Concentration; D011141:Polyuria / Q000503:physiopathology*; D011336:Probability; D011379:Prognosis; D011446:Prospective Studies; D012044:Regression Analysis; D018570:Risk Assessment; D012462:Saline Solution, Hypertonic; D012720:Severity of Illness Index; D012737:Sex Factors; D016482:Urinalysis; D014563:Urodynamics; D014882:Water-Electrolyte Balance / Q000502:physiology
chemical_list: D012462:Saline Solution, Hypertonic; D001127:Arginine Vasopressin