Urine concentration and enuresis in healthy preschool children
R. A. Mevorach, G. A. Bogaert and B. A. Kogan
Department of Urology, University of California School of Medicine-San Francisco.
OBJECTIVES: To determine whether children concentrate their urine overnight
and to assess the correlation between specific gravity of a first morning
urine specimen and the results of a questionnaire concerning bedwetting,
voiding habits, and continence in 47 healthy children aged 3 to 6 years.
DESIGN: A prospective observer-blinded consecutive sample. SETTING: Two San
Francisco, Calif., preschools. PARTICIPANTS: Forty-seven children attending
preschool during the study period. MEASUREMENTS/MAIN RESULTS: Forty of 47
children had a urine specific gravity greater than 1.020. None of these
children wet the bed during this study, although four (11%) of 36 had a
history of bedwetting. Furthermore, seven children with a urine specific
gravity of 1.015 or lower had a history of bedwetting and wet the bed
during this study. A voiding frequency of six or more times per day, by
history, was associated with a 3:1 relative risk of bedwetting but did not
segregate children with primary enuresis from those with secondary
enuresis. CONCLUSIONS: Our results indicate that healthy children aged 3 to
6 years are able to concentrate their urine. In addition, urine specific
gravity was an accurate predictor of the presence of nocturnal enuresis in
this group of children. Our results suggest that a specific gravity of the
first morning urine specimen should be correlated with appropriate history
before extensive diagnostic evaluation or empiric therapy is performed in
children with nocturnal enuresis.
