Background: Pseudohypoaldosteronism (PHPA1) is a disorder of impaired renal electrolytes re-absorption and excretion. Primary PHPA1 has two clinically and genetically distinct forms: (i) Renal autosomal dominant form, which involves a mutation in the mineralocorticoid receptor; (ii) Systemic autosomal recessive form, which involves a mutation in the epithelial sodium channel. PHPA1 can be also transient secondary to urinary tract infections (UTI)/malformations.
Objective and hypotheses: To emphasize the nature of secondary PHPA1 and the need for long-term follow-up.
Method: Case presentation of a neonate with a salt-wasting crisis.
Results: A 17-day-old male presented with a two-day history of poor feeding, irritability and dyspnea. Physical examination revealed a baby in septic shock. Initial blood work showed severe hyponatremia (Na-121 Meq/l), hyperkalemia (K-9.2 Meq/l), metabolic acidosis (pH 6.6, HCO3- 2.2, pCO2 23.6), and elevated BUN, creatinine and urine Na/K ratio. The baby was treated intensively in the PICU with intravenous fluids, antibiotics, electrolyte and acid-base corrections and hydrocortisone. The differential diagnosis included congenital adrenal disorders, Barters syndrome and forms of PHPA1. Further labs revealed normal cortisol, normal androgens, high aldosterone (109,000 pmol/l, normal range up to 4000 pmol/l) and high renin acitivity (>50 ng/ml/h). Microbiology cultures were positive for E. coli bacteremia and UTI. Renal ultra-sound was normal and cystogram showed vesico-urethral reflux. Despite normal electrolytes, due to failure to thrive and persistently high aldosterone and renin levels we added salt supplements and weight gain improved. Infants sweat test and paternal aldosterone and renin were normal. Finally, at the age of 2 years aldosterone and renin levels returned to normal.
Conclusion: We present a case of secondary PHPA1 due to E. coli urosepsis in a baby with vesico-urethral reflux. It emphasizes how secondary PHPA1 is part of the differential diagnosis of a salt-wasting crisis and the need for a long-term management.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology