BACKGROUND: Congenital urologic malformations occur with an incidence of 1:100 to 1: 200, leading to an increased risk of urinary tract infections. However, most patients remain without symptoms; serious electrolyte imbalance is rare. MATERIAL AND METHODS: We report two infants who were admitted to hospital because of failure to thrive and poor weight gain. Both children had severe hyponatraemia and hyperkalaemia. Further work-up established pseudohypoaldosteronism secondary to dilated vesicoureteral reflux and urinary tract infection. Based on a literature search in PubMed, a short overview of this rare condition is presented. RESULTS AND INTERPRETATION: Infants younger than 6 months of age with urologic malformations, and in most cases concomitant urinary tract infections, may develop secondary pseudohypoaldosteronism. The pathogenesis of this condition is probably a result of high intrarenal pressure, inflammation and immaturity of the tubular function leading to tubular resistance to aldosterone. The major symptoms are failure to thrive, poor weight gain, and signs of dehydration. Laboratory studies show hyponatraemia, hyperkalaemia and high levels of plasma renin activity and aldosterone. Treatment involves fluid resuscitation, sodium supplementation and antibiotic treatment of concomitant urinary tract infection. The most important differential diagnosis is the salt-losing form of congenital adrenal hyperplasia. A thorough endocrinologic and urological work-up, including abdominal ultrasound examination and urine analysis, may lead to correct diagnosis and treatment.
BACKGROUND:Congenital urologic malformations occur with an incidence of 1:100 to 1: 200, leading to an increased risk of urinary tract infections. However, most patients remain without symptoms; serious electrolyte imbalance is rare. MATERIAL AND METHODS: We report two infants who were admitted to hospital because of failure to thrive and poor weight gain. Both children had severe hyponatraemia and hyperkalaemia. Further work-up established pseudohypoaldosteronism secondary to dilated vesicoureteral reflux and urinary tract infection. Based on a literature search in PubMed, a short overview of this rare condition is presented. RESULTS AND INTERPRETATION:Infants younger than 6 months of age with urologic malformations, and in most cases concomitant urinary tract infections, may develop secondary pseudohypoaldosteronism. The pathogenesis of this condition is probably a result of high intrarenal pressure, inflammation and immaturity of the tubular function leading to tubular resistance to aldosterone. The major symptoms are failure to thrive, poor weight gain, and signs of dehydration. Laboratory studies show hyponatraemia, hyperkalaemia and high levels of plasma renin activity and aldosterone. Treatment involves fluid resuscitation, sodium supplementation and antibiotic treatment of concomitant urinary tract infection. The most important differential diagnosis is the salt-losing form of congenital adrenal hyperplasia. A thorough endocrinologic and urological work-up, including abdominal ultrasound examination and urine analysis, may lead to correct diagnosis and treatment.