Hashimoto Disease

What is Hashimoto disease?

Hashimoto 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 which attack the thyroid gland. The damaged thyroid gland is less able to make thyroid hormone and this results in hypothyroidism. Hypothyroidism means that the thyroid gland does not produce enough thyroid hormone to meet the body's needs.

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 or breathing due to enlarged thyroid 
• Intolerance to cold
• Mild weight gain
• Fatigue
• Constipation
• Dry skin
• Hair loss
• Heavy and irregular menses
• Infertility or miscarriage
• Difficulty concentrating or thinking
• Decreased libido 

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?

Your doctor will perform a physical examination and order blood tests to measure your hormone levels; we collectively call these labs thyroid function tests (TFTs) - TSH, free T4, and total T3. 

• TSH test: TSH is hormone released from your pituitary gland when there is not enough thyroid hormone in the system. TSH will be high if there is not enough thyroid hormone in the system. Normal ranges for TSH vary lab by lab and also are dependent on age (TSH normally rises as we age). 
• Free T4 and total T3 test: T3 and T4 are thyroid hormones. A low level of free T4 and/or T3 test also suggest 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 may not. TPO antibodies may also be present in normal people without hypothyroidism.

How is Hashimoto disease treated?

Not everyone with Hashimoto disease has hypothyroidism. If you have positive TPO antibodies but thyroid hormone levels are normal, then observation with repeated thyroid function tests is often times recommended.  If thyroid hormone levels are low, then treatment often involves thyroid hormone replacement therapy.  If you have symptoms of hypothyroidism but the thyroid function tests are normal, then it is most likely that the symptoms are coming from a different cause than the thyroid. 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 related to multiple aspects such as your weight, if you remember to take medication, and how it is spaced out from food and other medication. To maintain consistent thyroid hormone levels in your blood, you should always take the same brand since not all medicines are exactly the same. You should not take calcium supplements or anti-acid medications with your thyroid medication.

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's disease?
• What should I do about my hypothyroidism if I want to get pregnant? 
• What medicines do I need? When should I take them? What medications or supplements should I avoid with my thyroid medications?
• How often should I see my doctor or get testing of my thyroid?
• What else can I do to stay healthy? 
• Should I see an endocrinologist for my care?