HYPOTHYROIDISM-PRIMARY HYPOTHYROIDISM

SUMMARY

1. The pituitary thyrotrophs become hyperplastic and may simulate a tumor-imaging shows a pituitary mass.

2. Free T4 is low, TRH and TSH levels increase, and the elevated TRH suppresses dopamine, which increases PRL.

3. This can mimic a prolactinoma.

4. Treatment with thyroxine replacement causes the thyrotrophs to shrink, and PRL levels to normalize.

Reference(s)

Wilkinson, I., Furmedge, D. and Sinharay, R. (2017). Oxford handbook of clinical medicine. Oxford: Oxford University Press. Get it on Amazon.
Feather, A., Randall, D. and Waterhouse, M. (2020). Kumar And Clark’s Clinical Medicine. 10th ed. S.L.: Elsevier Health Sciences. Get it on Amazon.
Hannaman, R. A., Bullock, L., Hatchell, C. A., & Yoffe, M. (2016). Internal medicine review core curriculum, 2017-2018. CO Springs, CO: MedStudy.
Therapeutic Guidelines. Melbourne: Therapeutic Guidelines Limited. https://www.tg.org.au [Accessed 2021].