Pseudohypoaldosteronism with pyloric stenosis--a patient report.

A 53 day-old infant was referred for failure to thrive and persistent vomiting with severe dehydration. He had hyponatremia and hyperkalemia. Pyloric stenosis was diagnosed by means of sonography. Poor weight gain, hyponatremia and hyperkalemia were still found after Fredet-Ramsted pyloromyotomy. A urinary tract infection, a high urinary Na+/K+ ratio, and high serum levels of aldosterone and renin were found at the second admission. Rehydration, hydrocortisone and florinef administration failed to correct hyponatremia and hyperkalemia, suggesting pseudohypoaldosteronism. This patient gained weight after treatment of his infection and salt replacement.