Pneumothorax and transient pseudohypoaldosteronism in an infant with hydronephrosis.

Pneumothorax and transient pseudohypoaldosteronism have been noted as complications of obstructive uropathy in infancy. However, they are rare complications, and there have been no reports of a patient with both pneumothorax and pseudohypoaldosteronism in obstructive uropathy. Here we describe a case of pneumothorax and transient pseudohypoaldosteronism in an infant with bilateral hydronephrosis due to ureteropelvic junction obstruction. Nephrostomy improved the patient's condition and laboratory findings rapidly. While the exact pathogenic mechanism of pneumothorax in patients with obstructive uropathy is unclear, some biochemical defects due to obstructive uropathy might impair fetal lung maturation, which results in pneumothorax.