Polyuric megalocystis.

We diagnosed and treated 5 children with huge bladders and hydroureteronephrosis secondary to polyuria, resulting from either familial nephrogenic diabetes insipidus, medullary cystic disease, central diabetes insipidus secondary to panhypopituitarism or psychogenic polydipsia. Polyuria was documented by the measurement of 24-hour urine volumes. The possibility of anatomic and physiologic outlet obstruction was eliminated by flowmetry, voiding cystourethrography and endoscopy.