title: Decreased reverse T3 levels in neonates with central hypothyroidism.
abstract: Concern arises when a sick infant is found to have a low serum T4, normal thyroid hormone binding, and a nonelevated thyroid-stimulating hormone. Hypothyroxinemia in this situation can result from either euthyroid sick syndrome or central hypothyroidism. To help distinguish between these diagnostic possibilities, we have measured reverse T3 and other thyroid function chemistries in six neonates who have central hypothyroidism in association with hypopituitarism. We found that these infants all had reverse T3 levels that were much lower than reported normal levels for premature and term neonates. This finding suggests that low reverse T3 levels can help to distinguish infants with central hypothyroidism from sick and well infants who tend to have relatively elevated reverse T3 levels.
authors.affiliation: Department of Pediatrics, Emory University School of Medicine, Atlanta, USA.
authors.forename: E M
authors.initials: EM
authors.lastname: Faase
authors.forename: L R
authors.initials: LR
authors.lastname: Meacham
authors.forename: C M
authors.initials: CM
authors.lastname: Novack
authors.forename: M I
authors.initials: MI
authors.lastname: Brakin
authors.forename: H D
authors.initials: HD
authors.lastname: Mosier
authors.forename: F L
authors.initials: FL
authors.lastname: Culler
mesh_terms: D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D006981:Hyperthyroxinemia / Q000175:diagnosis* / Q000235:genetics; D007018:Hypopituitarism / Q000150:complications / Q000175:diagnosis / Q000235:genetics; D007037:Hypothyroidism / Q000097:blood / Q000150:complications / Q000175:diagnosis* / Q000235:genetics; D007231:Infant, Newborn; D008297:Male; D012016:Reference Values; D013960:Thyroid Function Tests; D013972:Thyrotropin / Q000032:analysis / Q000097:blood; D013974:Thyroxine / Q000097:blood*; D014285:Triiodothyronine, Reverse / Q000032:analysis / Q000097:blood*
chemical_list: D014285:Triiodothyronine, Reverse; D013972:Thyrotropin; D013974:Thyroxine