title: Hook effect: a pitfall leading to misdiagnosis of hypoaldosteronism in an infant with pseudohypoaldosteronism.
abstract: 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 microg/l; normal upper limit 36 microg/l) and tetrahydroaldosterone (TH-Aldo: 5,749 microg/l; normal upper limit 36 microg/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.
authors.affiliation: Department of Pediatric Endocrinology, Faculty of Medicine, Erciyes University, Kayseri, Turkey. leylabakin@gmail.com
authors.forename: Leyla
authors.initials: L
authors.lastname: Akin
authors.forename: Selim
authors.initials: S
authors.lastname: Kurtoglu
authors.forename: Mustafa
authors.initials: M
authors.lastname: Kendirci
authors.forename: Mustafa Ali
authors.initials: MA
authors.lastname: Akin
authors.forename: Michaela F
authors.initials: MF
authors.lastname: Hartmann
authors.forename: Stefan A
authors.initials: SA
authors.lastname: Wudy
mesh_terms: D000450:Aldosterone / Q000097:blood*; D019405:Cytochrome P-450 CYP11B2 / Q000172:deficiency*; D003937:Diagnosis, Differential; D006801:Humans; D006947:Hyperkalemia; D006994:Hypoaldosteronism / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology; D007010:Hyponatremia; D007223:Infant; D008297:Male; D011546:Pseudohypoaldosteronism / Q000097:blood / Q000175:diagnosis* / Q000201:enzymology
chemical_list: D000450:Aldosterone; D019405:Cytochrome P-450 CYP11B2