What is Thyroiditis?
January 19, 2023
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What is Thyroiditis?

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The thyroid gland is a butterfly-shaped organ located in the neck that makes and releases  thyroid hormones. These important hormones affect almost all cells, tissues, and organs in your body, controlling the metabolism, digestion, cognitive function, and more (Cleveland Clinic, 2022). The medical term for thyroid inflammation is thyroiditis. In this blog we will explain what thyroiditis is, the different types of thyroiditis that can occur, and how you can get tested. Read on to find out more.

All about thyroiditis

Thyroiditis is swelling or inflammation of the thyroid gland. It can occur for several different reasons and can cause varying symptoms. Thyroiditis progresses in stages, and at different points cause both over- and under-production of thyroid hormones. 

  1. Thyrotoxic Phase: In the first stage of thyroiditis, the thyroid becomes inflamed and releases too many hormones, causing thyrotoxicosis. Early stage thyroiditis can cause symptoms of an overactive thyroid (hyperthyroidism) due to the high amounts of hormones. 
  2. Hypothyroid Phase: After the thyroid releases all of its hormones in the first stage, it lacks adequate hormones for normal function. This is known as the second stage of thyroiditis and leads to symptoms of an underactive thyroid (hypothyroidism). 
  3. Euthyroid Phase: In the third stage of thyroiditis, thyroid hormone levels return to normal. This can occur once the thyroid recovers from the inflammation, or may occur briefly in between the first and second stage. Not all causes of thyroiditis return to normal, with some remaining in the hypothyroid stage.

Source: Cleveland Clinic, 2022

What are the symptoms of thyroiditis?

Because there are several different types of thyroiditis with varying causes, symptoms can differ slightly. However, most types of thyroiditis have a phase in which the thyroid is overactive (hyperthyroidism) and a phase in which it is underactive (hypothyroidism).

Symptoms of hyperthyroidism include:

  • Weight loss
  • Trouble sleeping
  • Rapid heartbeat
  • Fatigue
  • Muscle weakness
  • Anxiety or irritability
  • Hair loss
  • Persistent thirst
  • Eye problems
  • Swelling in the neck caused by an enlarged thyroid (goiter)

Source: NHS, 2019

Symptoms of hypothyroidism include:

  • Weight gain
  • Fatigue
  • Dry skin
  • Depression
  • Muscle cramps
  • Brittle hair and nails
  • Irregular periods

Source: NHS, 2021

Types of thyroiditis

Thyroiditis can have several causes, including infections, autoimmune diseases, certain medications, and after childbirth. The different types of thyroiditis are explained below.

Postpartum thyroiditis

Postpartum thyroiditis is an inflammation of the thyroid gland that occurs after childbirth. It is most common in women with type 1 diabetes or who have a previous history of postpartum thyroiditis (NHS, 2022). During postpartum thyroiditis, the immune system attacks the thyroid approximately 6 months after giving birth. This can cause the three stages of thyroiditis listed above, including phases of both hyper- and hypo-thyroidism. However, not all women with postpartum thyroiditis will go through both of these phases.

In most women who experience postpartum thyroiditis, thyroid function returns to normal within 12 months of giving birth. However, low thyroid hormone levels can sometimes be permanent.

Silent thyroiditis

Silent thyroiditis is similar to traditional thyroiditis except that it does not cause pain in the thyroid gland (goiter). Like other types of thyroiditis, the exact reason it occurs is unknown, but it most commonly occurs during the postpartum period, as well as from certain drugs or chemotherapy. Unlike postpartum thyroiditis, silent thyroiditis can affect both men and women of all ages (NHS, 2022). Since silent thyroiditis does not cause pain or tenderness in the neck, it may go undiagnosed until symptoms of hypothyroidism appear (Braunstein, 2022). 

Viral thyroiditis (Quervain’s disease)

Viral thyroiditis is believed to be caused by viral infections of the upper respiratory tract, such as a cold or the common flu (Penn Medicine). Although the precise cause is not known, it is believed to be associated with the inflammation that occurs during a viral infection, and usually occurs 2-8 weeks after the onset of virus symptoms. Viral thyroiditis most often affects middle aged women, but is possible in both men and women of all ages. This condition is also known as subacute thyroiditis because it is characterized by pain and swelling in the thyroid gland. It may take weeks or months before the thyroid recovers completely, although low thyroid hormone levels may be permanent.

Thyroiditis due to Hashimoto’s disease

Hashimoto’s thyroiditis is an autoimmune disease in which the body makes antibodies that attack the thyroid gland. It is not known exactly what causes Hashimoto’s disease, but it is believed to be a combination of genetics and environmental triggers, such as stress or radiation exposure. As the immune system attacks the thyroid gland, cells that make thyroid hormones die. This usually results in a decrease in thyroid hormones (hypothyroidism). 

Hashimoto’s disease is about eight times more common in women than in men and is more common in people with a family history of thyroid or autoimmune diseases. The disease mainly manifests itself in women between the ages of 30 and 50, but can occur at any age (Mayo Clinic, 2022).

Drug-induced thyroiditis

Some medications can damage the thyroid and cause either hypo- or hyperthyroidism. This rare condition can be caused by medications such as amiodarone, interferons, cytokines, and lithium (Cleveland Clinic, 2022). Drug-induced thyroiditis only occurs in a small percentage of people who use these medications.

Radiation-induced thyroiditis

Cancer treatment involving radiation or hyperthyroidism treatment that involves radioactive iodine can damage the thyroid and lead to thyroiditis. Symptoms of low thyroid hormones from radiation-induced thyroiditis are often permanent and require medication on a long-term basis (NHS, 2022). 

How does thyroiditis develop?

Thyroiditis is caused by some kind of attack of the thyroid, such as from viruses, medications, or autoimmune diseases. The most common cause of thyroiditis is autoimmune disease, in which the immune system accidentally attacks the thyroid rather than protecting it (American Thyroid Association). Autoimmune conditions that can cause thyroiditis include type 1 diabetes and rheumatoid arthritis.

How is thyroiditis diagnosed?

If you suspect that you have thyroiditis, speak to your GP. They will perform a physical exam and ask you about your symptoms and medical history (Cleveland Clinic, 2022). If they suspect you have thyroiditis, they will order blood tests or a thyroid ultrasound to check its function.

It is also possible to test your thyroid hormone levels from home. Using Homed-IQ’s Thyroid Test you can check for key thyroid hormones that may indicate the presence of hypothyroidism or hyperthyroidism. The test involves a finger prick blood sample that is collected at home and then sent to a laboratory for analysis. The laboratory report can be brought to your doctor for further evaluation if needed. To learn more about thyroid hormones and their optimal levels, read our article “What are normal thyroid values?

Can you prevent thyroiditis?

Unfortunately, in most cases thyroiditis cannot be prevented. If you are taking medications that carry a risk of thyroiditis, speak to your doctor about the potential risks. The most effective way to prevent serious symptoms from thyroiditis is to be aware of the symptoms and catch them early. Checking your thyroid hormones with a home test can help.

Thyroiditis can have various causes, including recent childbirth, viral infections, and autoimmune conditions. Most people with thyroiditis recover completely after a few months, and those who have persistent low thyroid hormone levels can lead a normal life with hormone replacement therapy. If you are concerned about thyroid disease, speak to your GP.

References

Braunstein, G. D. (2022, December 14). Silent Lymphocytic Thyroiditis. MSD Manual Professional Edition. https://www.msdmanuals.com/professional/endocrine-and-metabolic-disorders/thyroid-disorders/silent-lymphocytic-thyroiditis

Hashimoto’s disease – Symptoms and causes. (2022, January 15). Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/hashimotos-disease/symptoms-causes/syc-20351855

NHS website. (2021a, November 18). Symptoms. nhs.uk. https://www.nhs.uk/conditions/overactive-thyroid-hyperthyroidism/symptoms/

NHS website. (2021b, November 18). Symptoms. nhs.uk. https://www.nhs.uk/conditions/underactive-thyroid-hypothyroidism/symptoms/

NHS website. (2022, April 21). Thyroiditis. nhs.uk. https://www.nhs.uk/conditions/thyroiditis/

Penn Medicine. (n.d.). Subacute Thyroiditis. Penn Medicine. https://www.pennmedicine.org/for-patients-and-visitors/patient-information/conditions-treated-a-to-z/subacute-thyroiditis

Thyroiditis: Types, Causes, Symptoms, Diagnosis & Treatment. (n.d.). Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/15455-thyroiditis

About the author

Lauren Dobischok

Lauren is a health scientist and science communicator living in the Netherlands. With a background in epidemiology, her goal is to create accurate scientific content that is easy to understand and empowers people to make informed decisions. Her favourite topics to discuss are public health, infectious diseases, and dispelling myths and misconceptions about health topics with research. Coming from Canada, Lauren prefers to spend her free time learning Dutch and exploring the interesting sights this small country has to offer!