The thyroid gland, located at the front of your neck, produces two thyroid hormones, thyroxine (T4) and triiodothyronine (T3). T4 and T3 regulate how the body uses energy. This is sometimes called your metabolism.
How well the thyroid works is controlled by another gland called the pituitary, located at the base of the brain. The pituitary produces thyroid-stimulating hormone (TSH), which tells the thyroid to produce T4 and T3.
Hashimoto’s disease, also known as Hashimoto’s thyroiditis, is an autoimmune disease. This means your immune system, which normally protects your body and helps fight disease, produces antibodies and attacks the thyroid gland. The damaged thyroid gland is less able to make thyroid hormone, and hypothyroidism can result. Hypothyroidism means that the thyroid gland does not produce enough thyroid hormone to meet the body’s needs.
Anyone can develop Hashimoto’s disease, but it occurs more often in women and those with a family history of thyroid disease. It also occurs more often as people get older. People with other autoimmune disorders are more likely to develop Hashimoto’s disease. The hypothyroidism caused by Hashimoto’s disease progresses slowly over months to years. Its symptoms vary from person to person.
Hashimoto’s disease is the most common cause of hypothyroidism in the United States.
If left untreated, hypothyroidism caused by Hashimoto’s disease can lead to serious complications:
Diagnosis begins with describing any symptoms to your doctor. A physical examination of the neck may reveal a slightly enlarged thyroid gland. Blood tests help confirm the diagnosis.
Not everyone with Hashimoto’s disease has hypothyroidism. If you do not have a thyroid hormone deficiency, your doctor may recommend regular observation rather than treatment with medication. If you do have a deficiency, treatment involves thyroid hormone replacement therapy. The most effective treatment is a synthetic (man-made) T4 medicine called levothyroxine.
Levothyroxine is identical to the T4 produced by your body. A daily pill can restore normal levels of thyroid hormone and TSH in your bloodstream and make your thyroid function normal. You will probably need to take this medicine daily for the rest of your life, but your dose may need to be adjusted from time to time. To maintain consistent thyroid hormone levels in your blood, you should always take the same brand since not all medicines are exactly the same.
People are not routinely screened for hypothyroidism. However, if you are at risk for thyroid disease and are thinking about getting pregnant, you should be tested. Hypothyroidism is easily treated and you can protect your child from birth defects.