An Evaluation of the Thyrotrophin-Releasing Hormone Stimulation Test in Paediatric Clinical Practice

Abstract

Aim: 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. Methods: 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. Results: 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 (FT₄) or later developed low FT₄ and were treated with thyroxine. All those with subnormal TSH responses had normal FT₄ and were not treated. The TRH test did not reliably discriminate between hypothalamic and pituitary disorders. Conclusions: The TRH test did not give useful clinical information. Clinical decisions regarding thyroxine treatment were based on FT₄, not the TRH test. The TRH test should be abandoned in paediatric practice.