The TRH test is a valuable diagnostic test in central hypothyroidism with low T4

Smith* Liv Norma; Christensen* Sara Ellegaard; Christian Rosendal; Gulisano Helga Angela; Kare Ettrup; Nielsen Eigil H; Jesper Karmisholt; Jakob Dal

doi:10.1530/endoabs.90.P405

P405

Prev Next

Section Contents Cite

Endocrine Abstracts (2023) 90 P405 | DOI: 10.1530/endoabs.90.P405

ECE2023 Poster Presentations Pituitary and Neuroendocrinology (123 abstracts)

The TRH test is a valuable diagnostic test in central hypothyroidism with low T4

Liv Norma Smith* ¹ , Sara Ellegaard Christensen* ¹ , Christian Rosendal ¹ , Helga Angela Gulisano ² , Kåre Ettrup ² , Eigil H Nielsen ¹ , Jesper Karmisholt ¹ & Jakob Dal ^1,3

Err

Author affiliations

¹Aalborg University Hospital, Endocrinology, Aalborg, Denmark; ²Aalborg University Hospital, Neurosurgery, Aalborg, Denmark; ³Steno Diabetes Center North Jutland, Aalborg, Denmark

Objective: To evaluate the value of the thyrotropin-releasing hormone (TRH) test in the diagnosis of central hypothyroidism (CH) in patients with pituitary disease.

Methods: Systematic evaluation of 368 TRH tests including measurements of TBG corrected thyroxine (T4_corr), baseline TSH (TSH₀) and fold and absolute TSH increase (TSH_fold, TSH_absolute) in patients with pituitary disease.

Results: Patients diagnosed with CH (n=40) show comparable TSH₀ (P-value 0.57) but lower T4_corr (P-value 0.001) and TSH_fold response (P-value 0.001) compared to patients without CH. In 54% (44 of 81 cases) of the patients with low T4_corr, the CH diagnosis was rejected based on a high TSH_fold. In these cases, a spontaneous increase and normalisation in T4_corr (62 to 74nmol/l, P-value 0.001) was observed during the follow-up period (7.7 years, SD ±4.9). Two of the 44 patients (4.5%) were started on replacement therapy due to spontaneous deterioration. In patients with normal T4_corr (n=258), no patients were diagnosed with CH based on the TRH test. Patients diagnosed with CH reported significantly more symptoms of hypothyroidism (P-value 0.006), although, symptoms were reported in most patients with pituitary disease. There were only mild adverse effects related to the TRH test except for one case (0.3%) with a pituitary apoplexy.

Conclusions: The TRH test is a useful and safe diagnostic test but could be reserved for patients with pituitary disease and a low T4. Approximately 50 % of patients with a low T4_corr were considered to have normal pituitary thyroid function based on the TRH test results.