HYPERNATRIURIA AND KALIURESIS IN ENURETIC CHILDREN AND THE DIURNAL-VARIATION

Purpose: We investigate the underlying pathophysiological cause of pri mary nocturnal enuresis by comparing electrolyte alterations in urine samples of enuretics during the daytime and nighttime compared with th ose of nonenuretic subjects. Materials and Methods: Urine output, urin e specific gravity and urinary electrolytes in 15 enuretic and 12 none nuretic children were measured. We collected daytime serum and urine s amples of children fed a similar diet between 7 a.m. and 7 p.m., and n ighttime between samples 7 p.m. and 7 a.m. Urinary calcium/creatinine ratio, tubular reabsorption of phosphorus and excretions of fractional sodium and potassium were calculated. Results: There was no significa nt difference between the calcium/creatinine ratio ratios. There was a significant increase in fractional sodium and fractional potassium va lues in enuretics compared to nonenuretics during the day and at night . Daytime and nighttime fractional sodium and fractional potassium val ues in enuretics were similar. In contrast to nonenuretics, enuretic p atients had no diurnal variation of fractional sodium. There was signi ficant positive correlation between bedwetting status, and fractional sodium and fractional potassium. Conclusions: Since sodium and potassi um excretions were higher in enuretic patients than nonenuretic childr en, and no significant diurnal variation in urinary excretion of these ions there might be a difference in the mechanism of reabsorption of sodium and potassium between enuretic and nonenuretic children.