Hook Effect: A Pitfall Leading to Misdiagnosis of Hypoaldosteronism in an Infant with Pseudohypoaldosteronism

Akın L. , Kurtoglu S. , Kendirci M. , Akın M. A. , Hartmann M. F. , Wudy S. A.

HORMONE RESEARCH IN PAEDIATRICS, vol.74, no.1, pp.72-75, 2010 (Journal Indexed in SCI) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 74 Issue: 1
  • Publication Date: 2010
  • Doi Number: 10.1159/000281404
  • Page Numbers: pp.72-75


We report herein the case of a premature infant who presented with failure to thrive, hyponatremia, hyperkalemia and metabolic acidosis. Initial serum hormone profiling suggested isolated hypoaldosteronism (aldosterone: 0.01 pg/ml, normal range: 50-900 pg/ml). A gas chromatography-mass spectrometry spot urinary steroid profile showed grossly elevated levels of 18-hydroxy-tetrahydro-11-dehydrocorticosterone (18-hydroxy-THA: 5,893 mu g/l; normal upper limit 36 mu g/l) and tetrahydroaldosterone (TH-Aldo: 5,749 mu g/l; normal upper limit 36 mu g/l) which are aldosterone precursor metabolite and aldosterone metabolite, respectively. Thus, aldosterone synthase deficiency was excluded and pseudohypoaldosteronism (PHA) was suggested. A repeated test after dilution of the serum revealed a very high level of aldosterone (6,490 pg/ml), confirming the diagnosis of PHA in this case. Copyright (C) 2010 S. Karger AG, Basel