Background: Pseudohypoaldosteronism type I (PHA1) is a rare disease of mineralocorticoid resistance (MR). Neonatal manifestation leads to life-threatening dehydration due to massive salt-loss, acidosis and frequently, failure to thrive. Two clinically and genetically distinct forms exist, namely systemic and renal PHA1 caused by mutations in the subunit genes (SCNN1A, SCNN1B, SCNN1G) of the epithelial sodium channel (ENaC) and mineralocorticoid receptor coding gene NR3C2.
Case presentation: After an uneventful pregnancy, a eutrophic term male newborn presented poor feeding and some degree of respiratory distress within the first hours of life and was admitted to a neonatal unit. Family history was inconspicuous, as he was the second child of non-related Turkish and otherwise healthy parents. Antibiotic therapy to treat suspected neonatal infection was initiated immediately, as was additional intravenous fluid support, leading to apparent stabilisation. Unfortunately, on the 6th day of life his condition began to progressively deteriorate due to respiratory distress secondary to dehydration and severe electrolyte-imbalance as in neonatal manifestation of congenital adrenal hyperplasia with hyponatraemia, hyperkalaemia and metabolic acidosis. Medical therapy with a stress dose of hydrocortisone was attempted without convincing success. The boy was therefore referred to the neonatal ICU of our tertiary medical centre on his 7th day of life. Surprisingly, neonatal screening revealed normal 17-a-hydroxyprogesterone levels (17-a-OHP), but elevated plasma renin and aldosterone concentrations at the same time. Of note, impressive salt-crystal formations on the eyelids were macroscopically visible on both sides! This is attributable to salt loss via the excretory meibomian glands, known to be specific clinical proof of a severe manifestation of systemic PHA1. Mutational analysis revealed a compound heterozygous SCNN1B mutation.
Conclusion: This infants clinical appearance provided impressive proof of primary PHA1. Life-saving specific therapy could be initiated in a timely manner.
01 - 03 Oct 2015
European Society for Paediatric Endocrinology