Hyperkalemia in neonates is defined by a potassium level greater than 6 mmol/L, being classified as severe if it exceeds 7 mmol/L. It most commonly occurs in very preterm infants born at less than 28 weeks of gestation and is rarer in term infants. Clinical signs during the neonatal period are non specific and often manifest as bradycardia or tachycardia. The causes are numerous, with some of the rarer causes including type 1 pseudohypoaldosteronism (PHA1), which is characterized by mineralocorticoid resistance leading to a severe early salt-wasting syndrome with life-threatening risks. We report the case of a neonate who presented with early respiratory distress syndrome and severe hyperkalemia at 48 hours of life. Laboratory examinations suggested a salt-wasting syndrome. Hormonal assessments revealed normal 17-OHP levels, with elevated renin and aldosterone. A diagnosis of type 1 pseudohypoaldosteronism was established. Treatment for hyperkalemia involved a full therapeutic escalation; however, unfortunately, the newborn died at 10 days of life.

Index terms: Term neonate, respiratory distress syndrome, dehydration, hyperkalemia, hyponatremia, salt-wasting syndrome, metabolic acidosis, aldosterone, renin, pseudohypoaldosteronism.