Background: Pseudohypoaldosteronism type 1 (PHA1) is a rare disease which is characterised by hyponatremia, hyperkalemia, metabolic acidosis and elevated levels of aldosterone and renin. Aldosterone resistance is caused either by a mutation of the mineralocorticoid receptor gene or the epithelial sodium channel (ENaC). First causes autosomal dominant PHA1, also called renal form, second is responsible for the more severe and systemic form of PHA1 and is inherited in an autosomal recessive pattern.
Case presentation: We present a 6 year old arabic boy, born preterm (33+1GW). The parents are related. At day 9 the boy was presented with failure to thrive, vomiting and fever. Hyponatremia (126 mmol/l) and hyperkalemia (8.9 mmol/l) but no metabolic acidosis was documented. The diagnostic work-up showed elevated levels of aldosterone 3 000 ng/l (normal: 70830 ng/l) and renin 1 000 ng/l (normal: 5.9132 ng/l) while 17-Hydroxyprogesterone, ACTH and cortisol were normal. Recurrent problems of the lower respiratory tract made the hypothesis systemic form of PHA1 very likely and we found an until then not described alteration in the SCNNA-Gene. Now the boy still needs sodium supplementation, but the amount could be reduced from ~40 to ~15 mmol/kg/d. Also he needs resonium and sodium bicarbonate, all is given by percutaneous gastrostomy. The boy develops well both somatic (height −0.14 SDS, MPH 1SDS, BMI −0.4 SDS) and mental, nevertheless we observed some life-threatening events which resulted from common infections and very frequent respiratory infections with the need for hospitalisation.
Conclusion: PHA 1 has to be included in the differential diagnoses of severe hyponatremia. A secure access way is very important for the outcome of patients. Consequent immunisation should be performed to avoid common infections. The development with adequate therapy seems to be normal.
01 - 03 Oct 2015
European Society for Paediatric Endocrinology