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Osmoregulatory function of the kidney in enuretic children
A A Kuznetsova1, Y V Natochin, A V Papayan
1St. Petersburg State Pediatric Medical Academy, Russia.
Insights
Children with nocturnal enuresis excrete more sodium, leading to increased nighttime urine. Desmopressin normalizes this, suggesting impaired ion reabsorption is key in bedwetting.
Area of Science:
- Pediatric Nephrology
- Urology
- Internal Medicine
Background:
- Primary nocturnal enuresis affects many children.
- Its exact cause, particularly renal handling of solutes and water, requires further elucidation.
Purpose of the Study:
- To investigate nocturnal urine production and solute excretion in children with primary nocturnal enuresis.
- To explore the role of ion reabsorption in the pathogenesis of nocturnal enuresis.
Main Methods:
- 24-hour urine collection in 20 children with nocturnal enuresis and 20 healthy controls.
- Measurement of urine osmolality, free water reabsorption, and excretion of osmotically active solutes, including sodium.
Main Results:
- No significant difference in nocturnal urine osmolality or free water reabsorption between groups.
- Enuretic children showed increased diuresis and natriuresis (sodium excretion).
- Desmopressin treatment normalized diuresis and natriuresis.
Conclusions:
- Nocturnal enuresis in these children is associated with increased solute excretion, particularly sodium.
- Impaired ion reabsorption, likely in the thick ascending Henle loop, may contribute to increased nocturnal diuresis and enuresis.
- Desmopressin effectively manages these physiological abnormalities.
Abstract:
Twenty children with primary nocturnal enuresis and 20 healthy children of the same age and sex were studied. Natural urination was used for the 24-h urine collection. It was found that urine osmolality and free water reabsorption during the night did not differ statistically significantly between the enuretic children and the healthy. The increased diuresis in the enuretic children was caused by a higher excretion of the osmotically active solutes, including sodium. Use of desmopressin reduced diuresis and natriuresis to normal levels. It is suggested that the main role in the pathogenesis of the studied form of nocturnal enuresis is played by a decrease in ion reabsorption, probably in the thick ascending Henle loop, which facilitates the increase in diuresis and occurrence of nocturnal enuresis.