Obstructive uropathy and nephrogenic diabetes insipidus in infants.

The syndrome of acute post-obstructive nephrogenic diabetes insipidus is a rare phenomenon. The lesion is acquired during the pre-diuretic phase, owing to antidiuretic hormone resistance of the distal tubule as well as a severe concentrating defect. The diuretic phase after relief of obstruction can result in a massive, sustained and life-threatening diuresis. Sodium restriction and thiazide diuretics produce a mild volume contracted state, enhancing sodium and water reabsorption, primarily in the proximal tubule and possibly in the distal tubule owing to aldosterone. The recognition and differentiation of this unique pyloric syndrome from other more common post-obstructive diuretic states are important for all urologists who are responsible for the care of children.