Primary hypothyroidism
Definition:
Primary 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 thyroid gland itself.
In primary hypothyroidism, the circulating levels of the thyroid hormones are low, however, the levels of the thyroid stimulating hormone (TSH) are high due a lack of thyroid hormone negative feedback on the anterior pituitary.
Common causes of primary hypothyroidism include iodine deficiency (which leads to
goiter), and
Hashimoto's disease, in which autoimmune antibodies destroy the ability of the thyroid gland to produce the thyroid hormones.
Related glossary terms/phrases:
HypothyroidismSecondary hypothyroidismTertiary hypothyroidism
Posted: Saturday, January 24, 2015
Last updated: Wednesday, March 12, 2025