An overview of Hashimoto’s disease

Hashimoto's disease is an autoimmune disorder affecting the thyroid gland. The thyroid is a butterfly-shaped gland located at the base of the neck just below the Adam's apple. The thyroid produces hormones that help regulate many functions in the body.

An autoimmune disorder is an illness caused by the immune system attacking healthy tissues. In Hashimoto's disease, immune-system cells lead to the death of the thyroid's hormone-producing cells. The disease usually results in a decline in hormone production (hypothyroidism).

Although anyone can develop Hashimoto's disease, it's most common among middle-aged women. The primary treatment is thyroid hormone replacement.

Hashimoto's disease is also known as Hashimoto's thyroiditis, chronic lymphocytic thyroiditis and chronic autoimmune thyroiditis.

Hashimoto’s hypothyroidism happens when the thyroid gland doesn’t make enough thyroid hormones to meet the body’s needs because its immune system has damaged it.

Thyroid hormones regulate metabolism, which is how you turn food into energy. Without enough energy, your body cannot operate normally and its functions begin to slow down.

Hashimoto’s disease is an autoimmune disease, which means the body’s immune system is attacking its own cells and organs. Normally, the immune system protects the body against infections caused by bacteria, viruses and other harmful substances.

In Hashimoto’s disease, the immune system makes antibodies that attack and damage the thyroid tissue. As a result, the thyroid gland becomes inflamed and the ability to make thyroid hormone becomes damaged, eventually leading to hypothyroidism.

Hashimoto's symptoms may be mild at first or take years to develop. The first sign of the disease is often an enlarged thyroid, called a goiter. The goiter may cause the front of your neck to look swollen. A large goiter may make swallowing difficult. Other symptoms of an underactive thyroid due to Hashimoto's may include:

1. Slowed heart rate

2. Depression

3. Irregular or heavy menstrual periods

4. Hair loss or thinning, brittle hair

5. Weight gain

6. Fatigue

7. Paleness or puffiness of the face

8. Joint and muscle pain

9. Constipation

10. Inability to get warm

11. Difficulty getting pregnant

First, your healthcare provider will take your medical history and perform a physical exam. He or she will feel your thyroid gland to determine if it is enlarged. Blood tests are also ordered. These include:

Thyroid stimulating hormone (TSH) test: A high TSH level most commonly means the thyroid gland is not producing enough T4 hormone. This lab is usually most consistent with a diagnosis of hypothyroidism or subclinical hypothyroidism.

Free T4 test: A low T4 level suggests that the person has hypothyroidism.

Antithyroid antibody test: Presence of antibodies indicates a higher risk of developing Hashimoto’s hypothyroidism.

The most common imaging test that may be ordered is an ultrasound of your thyroid gland. The ultrasound shows the size and appearance of the thyroid and if there are any nodules or growths in your neck area.

If Hashimoto’s disease does progress to hypothyroidism, usual treatment is a synthetic (man-made) form of thyroid hormone called levothyroxine (Synthroid®, Tirosint®, Levoxyl®, Levothroid®, Unithroid®).

This drug restores the normal function of the thyroid. You’ll need to take it every day for the rest of your life. Your providers and you will figure out how to adjust your dose to make sure that your hypothyroidism is kept under control.

The following factors are associated with an increased risk of Hashimoto's disease:

1. Sex : Women are much more likely to get Hashimoto's disease.

2. Age : Hashimoto's disease can occur at any age but more commonly occurs during middle age.

3. Other autoimmune disease : Having another autoimmune disease — such as rheumatoid arthritis, type 1 diabetes or lupus — increases your risk of developing Hashimoto's disease.

4. Genetics and family history : You're at higher risk for Hashimoto's disease if others in your family have thyroid disorders or other autoimmune diseases.

5. Pregnancy : Typical changes in immune function during pregnancy may be a factor in Hashimoto's disease that begins after pregnancy.

6. Excessive iodine intake : Too much iodine in the diet may function as a trigger among people already at risk for Hashimoto's disease.

7. Radiation exposure : People exposed to excessive levels of environmental radiation are more prone to Hashimoto's disease.

Thyroid hormones are essential for the healthy function of many body systems. Therefore, when Hashimoto's disease and hypothyroidism are left untreated, many complications can occur. These include:

Heart problems : Hypothyroidism can result in poor heart function, an enlarged heart and irregular heartbeats. It can also result in high levels of low-density lipoprotein (LDL) cholesterol — the "bad" cholesterol — that is a risk factor for cardiovascular disease and heart failure.

Goiter : A goiter is enlargement of the thyroid. As thyroid hormone production declines due to Hashimoto's disease, the thyroid receives signals from the pituitary gland to make more. This cycle may result in a goiter. It's generally not uncomfortable, but a large goiter can affect your appearance and may interfere with swallowing or breathing.

Sexual and reproductive dysfunction : In women, hypothyroidism can result in a reduced sexual desire (libido), an inability to ovulate, and irregular and excessive menstrual bleeding. Men with hypothyroidism may have a reduced libido, erectile dysfunction and a lowered sperm count.

Mental health issues : Depression or other mental health disorders may occur early in Hashimoto's disease and may become more severe over time.

Myxedema (miks-uh-DEE-muh) : This rare, life-threatening condition can develop due to long-term, severe, untreated hypothyroidism. Its signs and symptoms include drowsiness followed by profound lethargy and unconsciousness. A myxedema coma may be triggered by exposure to cold, sedatives, infection or other stress on your body. Myxedema requires immediate emergency medical treatment.

Poor pregnancy outcomes : Hypothyroidism during pregnancy may increase the risk of a miscarriage or preterm birth. Babies born to women with untreated hypothyroidism are at risk for decreased intellectual abilities, autism, speech delays and other developmental disorders.