[Pseudohypoaldosteronism type 1 in an infant with bilateral primary obstructive megaureter : a case report]

A 35-day-old male infant was referred to our hospital for bilateral hydroureteronephrosis on postnatal ultrasonography. He was born at 37 weeks and 2 days of gestation, weighing 2,765 g. He was diagnosed with bilateral primary obstructive megaureter. During observation, at 3 months and 2 weeks of age, he presented with dehydration and showed hyponatremia and hyperkalemia. An endocrinological examination led to a diagnosis of pseudohypoaldosteronism type 1 (PHA1). After bilateral percutaneous nephrostomy, PHA1 resolved. He underwent bilateral ureteral tapering and ureteroneocystostomy at 5 months and 3 weeks of age. Since PHA1 recurred after removal of urethral catheter, urethral catheter and bilateral double-J-stent was kept until 8 months old. He was followed-up until 3 years old with no signs of PHA1 recurrence. For an infant with obstructive uropathy or vesicoureteral reflux showing hyponatremia and hyperkalemia, PHA1 should be considered.