Crofton Patricia M, Tepper Leonie A, Kelnar Christopher J H
Department of Paediatric Biochemistry, Royal Hospital for Sick Children, Edinburgh, UK.
Horm Res. 2008;69(1):53-9. doi: 10.1159/000111796. Epub 2007 Dec 4.
The aim of this retrospective study was to evaluate the clinical usefulness of the thyrotropin-releasing hormone (TRH) test in children with suspected hypothalamic or pituitary dysfunction.
We reviewed the case notes of all patients in whom a TRH test had been performed over a 6-year period. Group 1 (n = 85, 34 males, aged 0.9-18.8 years) was the reference group with no evidence of hypothalamic, pituitary or thyroid dysfunction. Group 2 (n = 42, 24 males, 0.1-18.0 years) were being investigated for possible pituitary or hypothalamic insufficiency.
In Group 1, thyrotropin (TSH) responses were higher in females than males (p < 0.01). In Group 2, TSH responses were normal for gender in 26 patients, subnormal in 5, and exaggerated/delayed in 11. Four patients with normal TSH responses and 4 with exaggerated/delayed responses had persistently low free thyroxine (FT(4)) or later developed low FT(4) and were treated with thyroxine. All those with subnormal TSH responses had normal FT(4) and were not treated. The TRH test did not reliably discriminate between hypothalamic and pituitary disorders.
The TRH test did not give useful clinical information. Clinical decisions regarding thyroxine treatment were based on FT(4), not the TRH test. The TRH test should be abandoned in paediatric practice.
