A Case of pseudohypoaldosteronism type 1 with positive familial history

Pseudohypoaldosteronism type 1 (PHA1) is a rare congenital disease of mineralocorticoid resistance which is characterized by neonatal renal salt wasting, vomiting, dehydration and failure to thrive. The clinical presentation of the disease represented mostly during neonatal period with a wide spectrum of symptoms regarding to autosomal recessive (systemic) or dominant (renal) inheritance mode. Biochemically, it is represented by high levels of plasma renin and aldosterone, hyponatremia and hyperkalemia. In this report, we present a case with clinical and biochemical findings of PHA1 and a positive familial history of the disease in her sister. CASE REPORT: A 3 months old girl infant was admitted to paediatrics emergency because of poor weight gain. At the time of admission, she was alert but dehydrated without history of vomiting or diarrhea for 1 week which had been deteriorated in last two days. RESULTS: Hyponatremia, hyperkalemia, metabolic acidosis and persistent electrolytes abnormalities were detected with dehydration in spite of adequate treatment, absence of hyperpigmentation, normal 17-OH-P values, high levels of plasma renin and aldosterone. No evidence of adrenal hyperplasia or renal anomalies was seen on ultrasonography. Acceptable response was achieved with high doses of fludrocortisone (0.5 mg/day) and oral NaCl. These findings in addition to positive familial history led to the diagnosis of pseudohypoaldosteronism type 1. CONSLUSIONS: In any infant who presents with hyponatremia, hyperkalemia and metabolic acidosis and non-specific symptoms such as growth retardation, some rare diagnosis such as PHA1 should be considered.