Thyroid hormone replacement is required in a variety of situations but most of the time this is due to failure of the thyroid gland
Causes of Thyroid failure
- Surgical removal of the thyroid
- Radioiodine therapy
- Severe auto immune attack on the thyroid
- bacterial or viral infection and destruction
- genetic causes
The normal thyroid gland puts out a combination of T4 (Free thyroxine) and T3 ( Liothyronine) This is secreted into the blood and provides the means to feedback to the pituitary regarding levels of thyroid hormone in the blood.