Understanding Hashimoto's Disease: A Comprehensive Guide

Hashimoto's disease is the number one cause of hypothyroidism¹ in the United States. Hypothyroidism affects an estimated 5 out of every 100 people in the US. 

Hypothyroidism is another term for an underactive thyroid that leads to low energy levels and weight gain. The condition is known to affect more women than men.

What is Hashimoto's disease?

Hashimoto's disease, also known as ‘Hashimoto's thyroiditis,’ is an autoimmune disease that affects the function of the thyroid gland. This butterfly-shaped gland, located in the lower part of the neck, produces hormones that regulate critical bodily functions such as growth, development, weight, heart rate, and more.

Hashimoto's thyroiditis is a chronic inflammatory condition that causes damage to the thyroid, resulting in reduced hormone production. This condition is the most common cause of hypothyroidism, or underactive thyroid, in the US.

The thyroid and the autoimmune system

The thyroid is a key component of the autoimmune system. The autoimmune system makes antibodies to protect the body from bacteria and viruses. A healthy autoimmune system will only attack bad elements and leave the body itself alone.

When you have an autoimmune disease, the antibodies attack the glands and organs they are supposed to protect. With Hashimoto's disease, the antibodies attack the thyroid gland, leaving behind a buildup of white blood cells. Over time, this buildup will damage the thyroid, which is unable to produce the level of hormones the body needs.

Since the primary function of thyroid hormones is to control how the body uses energy, every organ of the body is affected when that hormone is lacking.

Symptoms of Hashimoto's disease

Although symptoms can also affect younger women, Hashimoto's disease is mainly found in older women.

The primary symptom of Hashimoto's disease is the enlargement of the thyroid gland in the form of a goiter. This can make your neck look swollen, and it can also interfere with the ability to breathe and swallow.

Symptoms of Hashimoto's thyroiditis develop slowly, and it usually does not appear until later in life. Other symptoms of Hashimoto’s disease and an underactive thyroid include:

• Excessive fatigue

• Slowed heart rate

• Pain in the muscles and joints

• Constipation

• Dry skin

• Depression and/or difficulty concentrating

• Brittle nails

• Puffiness in the neck area (goiter)

• Difficulty tolerating cold

Risk factors for developing Hashimoto's disease

Factors considered to put a person at an increased risk of developing Hashimoto's disease include:

• Gender: It is more common among women

• Age: It most commonly appears in middle age, although it can affect any age group

• Other autoimmune diseases: You have an increased risk of developing Hashimoto's disease if you suffer from another autoimmune disease, such as lupus, rheumatoid arthritis, Sjogren's, or type 1 diabetes

• Family history/genetics: If other members of your family suffer from thyroid disorders or autoimmune diseases, you are at a higher risk of developing Hashimoto's disease

• Pregnancy: According to the National Institute of Health², typical changes to immune system functions during pregnancy can contribute to a woman developing the disease after the baby is born

• Excessive iodine in the diet: Studies from 2019³ show that if a person is already at risk of Hashimoto's disease, a diet heavy in iodine may trigger the condition

• Radiation exposure: If a person is exposed to excessive levels of environmental radiation,  they may be at higher risk of developing Hashimoto's disease

Diagnosing Hashimoto's disease

The thyroid function tests that determine the presence of Hashimoto's disease are:

• Thyroid-stimulating hormone (TSH) test: When the results of the TSH test show high levels, it means that the thyroid is not producing enough T4 hormone. This result points to a diagnosis of hypothyroidism.

• T4 hormone: A low T4 test also suggests hypothyroidism.

• Antithyroid-antibody test: The presence of antithyroid antibodies indicates that the patient is at high risk for developing Hashimoto's disease. When Hashimoto's is present, a protein called ‘peroxidase’ (TPO) is present in the blood. Further lab tests may be ordered to confirm the presence of other antibodies associated with Hashimoto's thyroiditis.

The next step is usually an ultrasound of the thyroid. The results of the ultrasound will help rule out other causes of the symptoms, such as growths or nodules.

Treating Hashimoto's disease

Hashimoto's disease is treated according to the level of damage to the thyroid and whether the condition is severe enough to cause hypothyroidism.

If your condition is not hypothyroidism, your doctor will monitor your thyroid hormone levels but will not begin treatment. If hypothyroidism is present, the preferred treatment is hormone replacement therapy.

The drug levothyroxine is a replacement for the natural thyroid hormone thyroxine, known as T4. Since food can affect your body's ability to absorb this drug, it is recommended that you take it on an empty stomach 30 to 60 minutes before your first meal of the day.

When you should visit your healthcare provider

If you have already been diagnosed with Hashimoto's disease and are taking levothyroxine, you should seek medical attention if you think your condition is getting worse.

If your thyroid is noticeably more swollen, as happens when you develop a new goiter, you will need lab work to check your TSH, T4, and antibody levels.

You should also consult your doctor if any other hypothyroidism symptoms are getting worse, such as:

• Increased weight gain

• Dry skin

• An increase in your sensitivity to cold

• Muscle aches, pains, and weakness

• Constipation

• Memory issues

• Slow heartbeat

• Increased fatigue

The lowdown

Hashimoto's disease, also known as ‘Hashimoto's thyroiditis,’ is an autoimmune disease where antibodies attack the thyroid. This weakens the thyroid, reducing the production of thyroid hormones and resulting in an underactive thyroid condition known as ‘hypothyroidism’. Hashimoto's is the number one cause of hypothyroidism in the US.

While Hashimoto's disease is occasionally diagnosed in younger people, it primarily affects middle-aged and older people and more women than men.

It is diagnosed based on a combination of symptoms and blood work that measures the TSH and T4 thyroid hormones as well as the thyroid antibodies.

The first symptom of Hashimoto's is usually swelling of the thyroid in the form of a goiter. Other key symptoms of Hashimoto's disease are excessive fatigue and weight gain.

Hashimoto's is not usually treated unless it is causing hypothyroidism. When it is treated, the hormone replacement drug levothyroxine is quite effective. Once you are on hormone replacement therapy, if you notice new or increased symptoms of hypothyroidism, consult your physician so that they can check your TSH and T4 levels.