Hashimoto Disease

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James Hennessey, MD
Leonard Wartofsky, MD

Additional Resources
American Thyroid Association Mayo Clinic


What is Hashimoto disease?

Hashimoto disease, also known as Hashimoto's disease or 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. Hashimoto disease is the most common cause of hypothyroidism in the United States.

Anyone can develop Hashimoto 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 disease. The hypothyroidism caused by Hashimoto disease progresses slowly over months to years. Its symptoms vary from person to person.

What are the symptoms of Hashimoto disease?

Possible symptoms include:

  • Enlarged thyroid (or goiter)
  • Trouble swallowing
  • Intolerance to cold
  • Mild weight gain
  • Fatigue
  • Constipation
  • Dry skin
  • Hair loss
  • Heavy and irregular menses

What are the complications of Hashimoto disease?

If left untreated, hypothyroidism caused by Hashimoto disease can lead to serious complications:

  • Goiter, which can interfere with swallowing or breathing.
  • Heart problems such as enlarged heart or heart failure.
  • Mental health issues such as depression, decreased sexual desire, slowed mental functioning.
  • Myxedema coma, a rare life-threatening condition that can result from long-term untreated hypothyroidism. Myxedema coma requires immediate emergency treatment.
  • Birth defects. Babies born to women with untreated hypothyroidism are more likely to be stillborn or premature. They may also have lower IQ (intelligence) later in life due to underdevelopment of the brain while in the womb.

How is Hashimoto disease diagnosed?

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.

  • TSH test: A high TSH level means your pituitary is trying to get the thyroid to make more T4 because there is not enough in your system (hypothyroidism).
  • T4 test: A low level of T4 also suggests hypothyroidism.
  • Thyroid peroxidase (anti-TPO) antibody blood test: This test detects the presence of antibodies directed against the thyroid. Most people with Hashimoto disease have these antibodies, but people whose hypothyroidism is caused by other conditions do not.

How is Hashimoto disease treated?

Not everyone with Hashimoto 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.

Questions to ask your doctor

  • Do my symptoms mean I have hypothyroidism?
  • How can I tell if my hypothyroidism is caused by Hashimoto disease?
  • Is there any difference in the way hypothyroidism and Hashimoto disease are treated?
  • What medicines do I need? When should I take them?
  • How often should I see my doctor?