Hashimoto's Thyroiditis

Hashimoto’s thyroiditis is also known as chronic lymphocytic thyroiditis or autoimmune thyroiditis. It is an autoimmune condition that causes inflammation of and damage to the thyroid gland. This damage eventually leads to a reduction in the production of thyroid hormones and the presentation of hypothyroidism. Although it can affect any individual, it is most common in women between the ages of 30 and 50.

Causes

Hashimoto’s thyroiditis is caused by the production of an abnormal antibody by the immune system, that turns against the cells in the thyroid gland and attacks them. The exact pathogenesis of the condition is not fully understood, but there are several factors that may be involved in cause the autoimmune condition.

There appears to be a familial link and individuals with a family history of Hashimoto’s thyroiditis are more likely to be affected than the general population. This suggests that there may be a genetic link in causing the condition which is under current investigation.

Additionally, Hashimoto’s thyroiditis is also linked to other autoimmune conditions, such as:

• Addison’s disease
• type 1 diabetes
• rheumatoid arthritis
• pernicious anemia
• celiac disease

Some environmental factors may also be involved in causing Hashimoto’s thyroiditis. Excessive consumption of iodine may interfere with the production of thyroid hormones in susceptible individuals. Other chemicals, medications or infections also have the potential to cause the condition.

Symptoms

The symptoms of Hashimoto’s thyroiditis are primarily linked to an underactive thyroid gland, resulting from the autoimmune destruction of the cells in the gland. This precipitates non-specific symptoms such as:

• Fatigue
• Weight gain
• Cold intolerance
• Joint or muscle pain
• Constipation
• Dry skin and hair
• Heavy menstrual periods
• Difficulty conceiving
• Depression
• Impaired memory
• Bradycardia

Additionally, the inflammation of the thyroid gland can lead to the formation of a lump in the area of the thyroid gland, in the lower front part of the neck, known as a goiter.

Diagnosis

As the symptoms of Hashimoto’s thyroiditis are mostly a result of gradual reduction of the levels of thyroid hormones in the body, they tend to present very slowly. Therefore, the diagnosis of the condition is often delayed for several months or years.

During the initial medical history consultation and physical examination, signs and symptoms may be reported and investigated. The presence of a goiter should stimulate further testing for thyroiditis.

A blood test to investigate the thyroid function is a helpful indicator to measure the concentration of thyroid stimulating hormone (TSH) and thyroxine (T4) in the blood. An individual with Hashimoto’s thyroiditis will typically have elevated TSH and low T4 hormone levels.

An antithyroid antibody test can then be used to investigate the presence of autoantibodies such as anti-TG antibodies that attack the thyroglobulin protein in the thyroid, and anti-thyroperoxidase (TPO) antibodies that attack an enzyme that is crucial in the conversion of T4 to T3 hormone.

Other diagnostic tests that may be required in some cases include ultrasound, computed tomography (CT) scan and X-ray imaging.

Treatment

There is currently no cure for Hashimoto’s thyroiditis, and the reduced thyroid hormone levels are considered to be permanent. Instead, management of the condition typically focuses on symptomatic treatment and improving individual quality of life.

In the early stages of the disease, treatment may not be required. Regular monitoring for the progression of symptoms is recommended. For symptomatic patients, a thyroid hormone replacement such as levothyroxine is usually the best option. This medication should be taken on an ongoing basis to provide the body with the levels of thyroid hormone required.

Some patients may also require surgery. However, this is usually only needed if there is a large goiter that causes discomfort, or is ugly, or if there is a suspected cancer in the area.

References

• http://www.nhs.uk/Conditions/thyroiditis/Pages/Introduction.aspx#deQuervain
• http://www.niddk.nih.gov/health-information/health-topics/endocrine/hashimotos-disease/Pages/fact-sheet.aspx
• http://emedicine.medscape.com/article/120937-overview#showall
• https://www.nlm.nih.gov/medlineplus/ency/article/000371.htm
• http://www.thyroidawareness.com/hashimotos

Further Reading

• All Hashimoto's Thyroiditis Content

Written by

Yolanda Smith

Yolanda graduated with a Bachelor of Pharmacy at the University of South Australia and has experience working in both Australia and Italy. She is passionate about how medicine, diet and lifestyle affect our health and enjoys helping people understand this. In her spare time she loves to explore the world and learn about new cultures and languages.