affects the thyroid and is characterized by an underactive thyroid. Hashimoto’s disease responds well to treatment which involves replacement therapy with thyroid hormone.
Hashimoto's Disease Overview
Hashimoto’s disease (also known as Hashimoto's thyroiditis) is an autoimmune disease that affects the thyroid, a small gland at the base of the neck.
With Hashimoto’s disease, the immune system makes antibodies that damage thyroid cells and interfere with their ability to make thyroid hormone. Over time, thyroid damage can cause hypothyroidism (underactive thyroid). An underactive thyroid causes every function of the body to slow down, such as heart rate, brain function, and the rate your body turns food into energy. Hashimoto’s disease is the most common cause of an underactive thyroid. It is closely related to Graves’ disease, another autoimmune disease affecting the thyroid.
Hashimoto's disease is more common in women and usually shows up in middle age. It can also occur in men and women of any age and in children.
Symptoms of an underactive thyroid include fatigue, weight gain, puffy face, voice changes, cold sensitivity, thinning hair, slow heart rate, and more.
A thyroid function test is used to help detect Hashimoto's disease. Hashimoto’s disease responds well to treatment which involves replacement therapy with thyroid hormone.
Hashimoto's Disease Symptoms
Many people with Hashimoto’s disease go without symptoms for years. An enlarged, swollen thyroid, called a goiter, is often the first sign of disease.
Symptoms of an underactive thyroid include:
- Unexplained weight gain
- Pale, puffy face
- Hoarseness or abnormal voice changes
- Feeling cold
- Joint and muscle pain
- Dry, thinning hair
- Heavy menstrual flow or irregular periods
- A slowed heart rate
- Difficulty getting pregnant
Hashimoto's Disease Causes
Hashimoto’s disease is more common in women than in men. It usually shows up in middle age but it can occur in younger women. People who get Hashimoto’s disease often have family members who have thyroid or other autoimmune diseases. People who get Hashimoto’s disease sometimes have other autoimmune diseases, such as:
- Vitiligo — a disease that destroys the cells that give your skin its color
- Rheumatoid arthritis — a disease that affects the lining of the joints throughout the body
- Addison’s disease — a disease that affects the adrenal glands, which make hormones that help your body respond to stress and regulate your blood pressure and water and salt balance
- Type 1 diabetes — a disease that causes blood sugar levels to be too high
- Graves’ disease — a disease that causes the thyroid to make too much thyroid hormone
- Pernicious anemia — a disease that keeps your body from absorbing vitamin B12 and making enough healthy red blood cells
- Lupus — a disease that can damage many parts of the body, such as the joints, skin, blood vessels, and other organs
Many factors are thought to play a role in getting Hashimoto’s disease. These include:
- Genes. Some people are prone to Hashimoto’s disease because of their genes. Researchers are working to find the gene or genes involved.
- Gender. Sex hormones also might play a role. This may help to explain why Hashimoto’s disease affects more women than men.
- Pregnancy. Some women have thyroid problems after having a baby, which usually go away. But about 20 percent of these women develop Hashimoto’s disease in later years. This suggests that pregnancy might trigger thyroid disease in some women.
- Too much iodine and some drugs may trigger the onset of thyroid disease in people prone to getting it.
- Radiation exposure has been shown to bring on autoimmune thyroid disease. This includes radiation from the atomic bomb in Japan, the nuclear accident at Chernobyl, and radiation treatment of Hodgkin’s disease (a type of blood cancer).
Hashimoto's Disease Diagnosis
Diagnosis begins with a physical exam and medical history. A goiter, nodules, or growths may be found during a physical exam, and symptoms may suggest hypothyroidism. Health care providers will then perform blood tests to confirm the diagnosis. A blood test involves drawing blood at a health care provider’s office or a commercial facility and sending the sample to a lab for analysis. Diagnostic blood tests may include the:
- TSH test. The ultrasensitive TSH test is usually the first test performed. This test detects even tiny amounts of TSH in the blood and is the most accurate measure of thyroid activity available. Generally, a TSH reading above normal means a person has hypothyroidism.
- T4 test. The T4 test measures the actual amount of thyroid hormone circulating in the blood. In hypothyroidism, the level of T4 in the blood is lower than normal.
- antithyroid antibody test. This test looks for the presence of thyroid autoantibodies, or molecules produced by a person’s body that mistakenly attack the body’s own tissues. Two principal types of antithyroid antibodies are anti-TG antibodies, which attack a protein in the thyroid called thyroglobulin.
A health care provider may also order imaging tests, including an ultrasound or a computerized tomography (CT) scan.
Hashimoto's Disease Treatments
Treatment generally depends on whether the thyroid is damaged enough to cause hypothyroidism. In the absence of hypothyroidism, some health care providers treat Hashimoto’s disease to reduce the size of the goiter. Others choose not to treat the disease and simply monitor their patients for disease progression.
Hashimoto’s disease, with or without hypothyroidism, is treated with synthetic thyroxine, which is man-made T4. Health care providers prefer to use synthetic T4, such as Synthroid, rather than synthetic T3, because T4 stays in the body longer, ensuring a steady supply of thyroid hormone throughout the day. The thyroid preparations made with animal thyroid are not considered as consistent as synthetic thyroid (Levothyroxine) and rarely prescribed today.
Health care providers routinely test the blood of patients taking synthetic thyroid hormone and adjust the dose as necessary, typically based on the result of the TSH test. Hypothyroidism can almost always be completely controlled with synthetic thyroxine, as long as the recommended dose is taken every day as instructed.
During pregnancy, hypothyroidism is usually caused by Hashimoto’s disease and occurs in three to five out of every 1,000 pregnancies. Uncontrolled hypothyroidism raises the chance of miscarriage, premature birth, stillbirth, and preeclampsia—a dangerous rise in blood pressure in late pregnancy.
Untreated hypothyroidism during pregnancy may also affect the baby’s growth and brain development. Thyroid medications can help prevent these problems and are safe to take during pregnancy. Women with Hashimoto’s disease should discuss their condition with their health care provider before becoming pregnant.
Hashimoto's Disease Related Medications
Hashimoto's Disease Other Treatments
Thyroid hormone extracted from thyroid glands of pigs was the most common form of treatment for hypothyroidism before the synthetic form of T4 became commercially available. This pig-derived product, which contains both T4 and T3, is called Amour Thyroid. It is considered less reliable because its potency can vary from batch to batch which makes it more difficult to optimize thyroid hormone levels.