Tertiary hypothyroidism
Definition:
Tertiary hypothyroidism is characterized by abnormally low levels of thyroid hormone (T
3 and T
4) production, where the defect is at the level of the hypothalamus.
In tertiary hypothyroidism, the hypothalamus is unable to produce sufficient levels of thyrotropin release hormone (TRH). Low TRH levels lead to low production of the thyroid stimulating hormone (TSH) by the anterior pituitary gland which, in turn, leads to insufficient stimulation of the thyroid gland to produce the thyroid hormones (T
3 and T
4).
Thus, in tertiary hypothyroidism, the circulating levels of TRH, TSH, T
3, and T
4 are all abnormally low.
Related glossary terms/phrases:
HypothyroidismPrimary hypothyroidismSecondary hypothyroidism
Posted: Sunday, January 25, 2015
Last updated: Wednesday, March 12, 2025