The most common cause of hypothyroidism in Canada is due to an autoimmune condition called Hashimoto’s Thyroidiits. In this condition, either thyroperoxidase antibodies (TPOAb) or thyroglobulin antibodies (TgAb) will damage the thyroid gland resulting in impaired production of thyroid hormones. For those that have been diagnosed with Hashimoto’s thyroiditis, my approach involves lowering antibodies as much as possible through dietary, nutritional and medication interventions.
An iatrogenic illness is one that has been caused by a medical examination or treatment. If you have had hyperthyroidism (e.g. Grave’s disease) or have had thyroid cancer, you may have had a partial or total thyroidectomy (removal) or may have had a radioactive iodine treatment to destroy part of the gland. Most individuals end up with hypothyroidism after these treatments due to insufficient thyroid tissue remaining.
The thyroid gland needs various minerals and nutrients in order to produce thyroid hormones. If you are deficient in any of these building blocks, you may experience symptoms of hypothyroidism as the production of hormones slow down.
As mentioned previously, your body needs to convert thyroxine (T4) into the more active triiodothyronine (T3) in various tissues of the body using an enzyme called a deiodinase. In some people, this enzyme doesn’t function properly which results in having normal serum levels of TSH and T4 but deficient levels of T3. For many people with improper conversion, regular thyroid medications may not be sufficient to ease all symptoms and a more comprehensive treatment plan may need to be employed to address the various causes of poor conversion.
Thyroid Hormone Resistance
Thyroid hormone resistance is similar to insulin resistance in diabetics. In this condition, the body’s cells are not as responsive to thyroid hormones. Usually this presents as normal levels of T3 and T4 but elevations in TSH levels.
Secondary or Tertiary Hypothyroidism
Secondary and tertiary hypothyroidism are rare causes of hypothyroidism and are caused by disorders within the pituitary gland or hypothalamus in the brain, respectively. There are usually other concerning symptoms than just those associated with hypothyroidism in these cases.