Hook effect: A pitfall leading to misdiagnosis of hypoaldosteronism in an infant with pseudohypoaldosteronism

Akin L., Kurtoglu S., Kendirci M., KARAYOL AKIN A., Hartmann M. F., Wudy S. A.

Hormone Research in Paediatrics, vol.74, no.1, pp.72-75, 2010 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 74 Issue: 1
  • Publication Date: 2010
  • Doi Number: 10.1159/000281404
  • Journal Name: Hormone Research in Paediatrics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.72-75
  • Keywords: Hook effect, Hypoaldosteronism, Misdiagnosis
  • Ondokuz Mayıs University Affiliated: No


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 μg/l; normal upper limit 36 μg/l) and tetrahydroaldosterone (TH-Aldo: 5,749 μg/l; normal upper limit 36 μg/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. © 2010 S. Karger AG.