ESPE Abstracts

Background: Type 1 pseudohypoaldosteronism (PHA1) is a rare syndrome characterized by unresponsiveness to aldosterone. Diagnosis is established by high levels of aldosterone and plasma renin activity, associated with findings of hypoaldosteronism (hyponatremia, hyperkalemia and metabolic acidosis). When the inheritance pattern is autosomal recessive it expresses as a severe systemic disease and the mortality rate is high, especially in the neonatal period.

Case report: Male child with irrelevant gestational history. He had one sister with Chediak-Higashi syndrome but no parental consanguinity was found. Systemic PHA1 due to homozygous mutation in intron 3 of the SCNN1A gene was diagnosed in the neonatal period (severe hyperkalemia, hyponatremia, dehydration and acidosis). After numerous life-threatening crises he was discharged at five months-old under fludrocortisone, sodium supplement 33mEq/kg/day and cation-exchange resin. Until 2-years-old, medication was administered by nasogastric tube. He always maintained tight control of electrolyte balance and therapeutics but he was admitted several times in the emergency room with hypovolemic shock, requiring intensive treatment, and frequently nebulizer salbutamol and calcium gluconate. These incidents became less severe and less frequent with increasing age. Fludrocortisone and cation-exchange resin were stopped at 3-years-old. Hydrochlorothiazide was started from 18-months-old until 4-years-old. Sodium supplement ranged from 28-55mEq/kg/day. At 18-months-old, he had a tonic-clonic seizure in apirexy and after that six simple febrile seizures occurred (the last at 6 years-old). Electroencephalogram and brain magnetic resonance were normal. The child had an atopic dermatitis-like rash that worsened in hot environments, but has not occurred since 5-years-old. During follow-up, transient asymptomatic hypoglycemia and subclinical transient hypothyroidism were diagnosed. ACTH, cortisol, C-peptide, insulin, IGF-1 and ACTH stimulation-test were normal and there was no need for treatment. He underwent adenoidectomy and tonsillectomy for snoring and repeated upper respiratory tract infections, at 6-years-old. He was under a development stimulation program and actually, he is attending the 5th year of school with reasonable performance. WISC-III at 6-years-old, showed a lower IQ (75) and reassessment at 10-years-old showed similar results (72). He thrived very poorly during the first two years, and actually at 10-years-old, he maintains failure to thrive (height -2.2SDS, weight -0.9SDS) but regular growth velocity. He is prepubertal and his only medication is sodium supplementation (26mEq/kg/day).

Conclusion: Management of PHA-1 patients is challenging since there are no evidence-based recommendations and the long-term prognosis remains unclear. A multidisciplinary approach and rigorous follow-up are essential to have a controlled disease and an adequate growth and development.