Background: Pseudohypoaldosteronism type 1 (PHA1) is a rare syndrome characterized by unresponsiveness or resistance to the action of aldosterone. It manifests with persistent salt loss, resulting in hyponatremia, hyperkalemia and metabolic acidosis. High levels of aldosterone and renin activity, confirms the diagnosis. When the inheritance pattern is autosomal recessive it expresses as a severe systemic disease. Often occurs in the neonatal period and presents with recurrent episodes of salt loss that are life-threatening.
Objective and hypotheses:
Results: Male child with irrelevant gestational history. Ten-year-old sister with Chediak-Higashi syndrome. A recessive form of PHA1 (homozygous mutation of intron 3 of the SCNN1A gene) was diagnosed in the neonatal period (severe hyperkalemia, hyponatremia, dehydration and acidosis). After numerous life-threatening crisis he was discharged at five months-old under fludrocortisone 1.5 mg/day, sodium supplement 33 mEq/kg per day and cation-exchange resin 1 g/kg 5 times/day. He was admitted several times in the emergency room with hypovolemic shock, requiring intensive treatment, increasing of cation-exchange resin and frequently nebulized salbutamol and calcium gluconate. He always maintained tight control of electrolyte balance and therapeutics. Empirically, hydrochlorothiazide was started since eighteen months-old to four years-old (maximum dose 2 mg/kg per day). At this time, fludrocortisone was gradually reduced, and later, cation-exchange resin was also decreased. Sodium supplement ranged from 28 to 55 mEq/kg per day. At 18 months-old, his first seizure occurred in apirexy, the other six were simple febrile seizures. Electroencephalograms were normal. Analytical monitoring showed transient subclinical hypothyroidism, asymptomatic hypoglycemia and normal ACTH, cortisol, C-peptide, insulin and IGF-1. ACTH stimulation test and brain magnetic resonance imaging were normal. Currently, at five years-old, he maintains failure to thrive (height 2.61 SDS, weight 3.53 SDS) with regular growth velocity and normal development. He only keeps sodium supplement.
Conclusion: We report this severe PHA1 case with poor initial prognosis but with favorable evolution. We discuss hydrochlorothiazide and fludrocortisone use in this pathology, despite the lack of evidence.
10 - 12 Sep 2016
European Society for Paediatric Endocrinology