We present a case of transient form of type 1 pseudohypoaldosteronism (S-PHA) in a 1.5-month-old male infant who presented with lethargy, failure to thrive, severe hyponatremia (Na=118 mmol/L), hypochloremia (Cl=93 mmol/L) and fever due to urinary tract infection. Potassium levels were normal. Markedly elevated serum aldosterone level and elevated serum renin confirmed the diagnosis of pseudohypoaldosteronism. Renal ultrasound showed grade III hydronephrosis on the left kidney while contrast-enhanced voiding urosonography excluded the existence of vesicoureteral reflux, which raised suspicion of obstructive uropathy at the level of vesicoureteral junction. Serum sodium normalized after several days of intravenous fluids and antibiotic therapy, after which oral supplementation of sodium was introduced. The levels of 17-hydroxyprogesterone, adrenocorticotropic hormone, cortisol and thyroid-stimulating hormone were normal. Functional magnetic resonance urography conducted at the age of 3 months confirmed the diagnosis of primary congenital obstructive megaureter and the infant was referred to a pediatric surgeon. Although a rare occurrence, S-PHA can be a potentially life-threatening condition in infants if not recognized and treated appropriately. Therefore, serum concentrations of electrolytes should be obtained in every child diagnosed with obstructive anomaly of the urinary tract and/or acute cystopyelonephritis. On the other hand, every child diagnosed with S-PHA should be evaluated for obstructive anomaly of the urinary tract.
Keywords: Obstructive megaureter; Pseudohypoaldosteronism; Unilateral hydronephrosis.
Sestre Milosrdnice University Hospital.