Hypothyroidism Causes and Risk Factors: Autoimmune disease, Hashimoto's disease and More

Hypothyroidism - Causes and Risk Factors

There are many reasons why hypothyroidism occurs. The more common causes include the following:

Hashimoto’s disease
This is the most common cause of hypothyroidism. It is an “autoimmune”, or “self-attacking-self” disease. It occurs when the body’s immune system mistakenly attacks thyroid cells and damages them. Over time, the thyroid gland fails, causing hypothyroidism.
Radioactive iodine treatment
Hypothyroidism often develops as a desired treatment goal after the use of radioactive iodine treatment for high thyroid hormone production (hyperthyroidism).
Thyroid operation
Previous thyroid surgery can cause hypothyroidism, especially if most of the thyroid gland has been removed.
Medication
Some medication including amiodarone and lithium can cause hypothyroidism
Subacute thyroiditis
This causes a painful inflammation of the thyroid. This causes a period of hyperthyroidism (high thyroid hormone level) as the damaged cells leak their hormone supply into the bloodstream, but this is followed by a period of hypothyroidism.
Congenital hypothyroidism
A baby may be born with an insufficient amount of thyroid tissue or a problem that does not allow normal thyroid hormone production

Less commonly, hypothyroidism can also be caused by problems in the pituitary gland, the “master hormone gland” that controls the thyroid gland.