What causes hypothyroidism?
There are several ways that a person can develop hypothyroidism, including:
- Autoimmune disease causes the body’s immune system to attack its own thyroid cells. Cell destruction leads to a deficiency in thyroid hormone secretion.
- Having treatment for an overly active thyroid gland, called hyperthyroidism (thyroid produces too much hormone). Patients being treated for hyperthyroidism are at risk of having their thyroid over-suppressed or damaged, both of which can lead to hypothyroidism.
- Thyroid removal: surgical removal of the thyroid may be required to treat thyroid nodules or thyroid cancer. Surgery can lead to hypothyroidism.
- Being born without a thyroid gland or with a defective thyroid is rare, but causes hypothyroidism.