News & Events

by Kimberly Dorris, GDATF Executive Director

What Causes Hashimoto’s Thyroiditis?

The immune system normally recognizes and destroys invaders like bacteria and viruses, as well as abnormal cells like those from cancers. However, in autoimmune diseases, the immune system mistakenly launches an attack against its own healthy tissues. In Hashimoto’s thyroiditis, the immune system’s attack targets the cells and tissues in the thyroid.

The Legacy of Dr. Hakaru Hashimoto: Discovering Hashimoto’s Thyroiditis

Also known as chronic autoimmune thyroiditis or chronic lymphocytic thyroiditis, Hashimoto’s thyroiditis is named for Dr. Hakaru Hashimoto, a Japanese physician and scientist. While working in a surgical department, Dr. Hashimoto examined thyroid tissue from four middle-aged women and noticed the infiltration of lymphocytes, a type of white blood cell. His findings were published in 1912 in Archiv Fur Klinishe Chirurgie, the German journal of clinical surgery.

At the time, Dr. Hashimoto was only 31, and this was his first and only publication on the thyroid! Dr. Hashimoto’s research career was cut short because he chose to return to his hometown to practice family medicine, where he was known to travel great distances by rickshaw to see patients. He contracted typhoid fever from a patient and died in 1934, long before there was widespread international recognition of his important discovery.

Hashimoto’s Risk Factors: Who’s Affected?

Who is most likely to get Hashimoto’s thyroiditis? According to the National Institutes of Health, about 5 in 100 people in the U.S. Have Hashimoto’s thyroiditis. Risk factors include:

• Having a family member with the disease
• Female sex (statistics vary, but Hashimoto’s thyroiditis is typically 4-10 times more common in women than in men)
• Age (cases often develop between age 30 and 50)
• History of other autoimmune diseases, including celiac disease, lupus, rheumatoid arthritis, Sjögren’s syndrome, or type 1 diabetes.

Symptoms of Hashimoto’s Thyroiditis

During the initial stages of Hashimoto’s thyroiditis, the immune system’s attack can result in stored hormone being released from the thyroid. If levels of thyroid hormone in the body become excessive (toxic), patients can experience classic symptoms of hyperthyroidism. But over time, the attack leaves the thyroid damaged and unable to produce enough thyroid hormone. Symptoms of hypothyroidism can include:

• Goiter (enlarged thyroid)
• Fatigue
• Constipation
• Heavy menstrual periods
• Cold intolerance
• Memory loss
• Facial puffiness
• Slower heart rate
• Dry skin and hair
• Unexplained weight gain
• Muscle aches and joint pain
• Hair loss
• Voice changes (hoarseness)

Another early sign of hypothyroidism is high cholesterol (hyperlipidimia). In fact, some medical organizations recommend thyroid function testing for patients with newly diagnosed hyperlipidemia. For some patients, treatment of the underlying hypothyroidism may help normalize cholesterol levels without the need for lipid lowering drugs.

Hashimoto’s Thyroiditis and Thyroid Eye Disease

Patients with Hashimoto’s thyroiditis can also experience eye symptoms. Although thyroid eye disease (TED) is more common in patients with Graves’ disease, a study out of Germany involving 700 patients with Hashimoto’s thyroiditis found that 6% had TED.

Diagnosing and Treating Hashimoto’s Disease

How do you diagnose Graves’ disease versus the toxic phase of Hashimoto’s thyroiditis? Both Graves’ and Hashimoto’s patients can have elevated Thyroid peroxidase antibodies (TPOAb) or Thyroglobulin antibodies (TgAb), but the presence of thyroid stimulating immunoglobulin (TSI) antibodies or Thyrotropin receptor antibodies (TRAb) will typically confirm Graves’ disease.  If the results aren’t conclusive, your doctor might order a Radioactive Iodine Uptake & Scan, which provides a snapshot of how the thyroid is taking up iodine. Graves’ disease typically results in a high uptake throughout the thyroid, with Hashimoto’s thyroiditis resulting in low uptake. (Another condition that can lead to excessive levels of thyroid hormone is an overactive thyroid nodule, which appears on the scan as high uptake only in the area where the nodule is located.)

As the National Institutes of Health explains, failure to treat hypothyroidism can lead to high blood pressure, high cholesterol, heart disease and heart failure, and a rare condition called myxedema, where all the body’s functions dangerously slow down.

We don’t currently have options to directly target the antibodies in Hashimoto’s thyroiditis, so treatment focuses on normalizing thyroid hormone levels. This is accomplished by taking thyroid hormone replacement (either a brand name medication or generic levothyroxine) typically for life.

Some patients report improved symptom management and quality of life with T3/T4 combination therapy. This has been somewhat controversial in the medical community, given that many randomized controlled trials haven’t shown a difference in how people feel on T4 monotherapy versus combination therapy. But as Dr. David Cooper explained in a recent webinar that GDATF co-hosted with the  American Association of Endocrine Surgeons, many prior studies “recruited everybody taking levothyroxine…but they didn’t exclusively study people who didn’t feel well.”

Thyroidectomy and Ongoing Research

Studies published in 2019 and 2020 indicated a possible role for thyroidectomy in patients with persistent symptoms from Hashimoto’s thyroiditis, but the results are somewhat controversial, and this decision must be weighed against the risks of thyroidectomy. However, surgery might be recommended for patients who have nodules that are malignant (or indeterminate) as well as patients with a goiter that is causing difficulties with breathing or swallowing.

Studies on diet and nutrition have not been conclusive.

There are a number of ongoing clinical trials exploring approaches for Hashimoto’s thyroiditis – for more information, visit clinicaltrials.gov.

Resources & Further Reading:

National Institutes of Health  National Institute of Diabetes and Digestive and Kidney Diseases. Hashimoto’s Disease.

Cleveland Clinic. Hashimoto’s disease. Accessed at https://my.clevelandclinic.org/health/diseases/17665-hashimotos-disease

John’s Hopkins Medicine. Hashimoto’s thyroiditis.

American Thyroid Association Downloadable Patient Brochures. https://www.thyroid.org/thyroid-information/

Healio. Hakaru Hashimoto: 1881-1934. Accessed at https://www.healio.com/news/endocrinology/20120325/hakaru-hashimoto-1881-1934.

Jeffrey Garber,  MD, FACP, MACE. Harvard Health Blog. Is there a role for surgery in treating Hashimoto’s thyroiditis? Accessed at https://www.health.harvard.edu/blog/is-there-a-role-for-surgery-in-treating-hashimotos-thyroiditis-2019081217443

Osowiecka K, Myszkowska-Ryciak J. The Influence of Nutritional Intervention in the Treatment of Hashimoto’s Thyroiditis-A Systematic Review. Nutrients. 2023 Feb 20;15(4):1041. doi: 10.3390/nu15041041. PMID: 36839399; PMCID: PMC9962371. Accessed at https://pubmed.ncbi.nlm.nih.gov/36839399/

Bianco AC. Emerging Therapies in Hypothyroidism. Annu Rev Med. 2024 Jan 29;75:307-319. doi: 10.1146/annurev-med-060622-101007. Epub 2023 Sep 22. PMID: 37738506; PMCID: PMC10843736. Accessed at https://pmc.ncbi.nlm.nih.gov/articles/PMC10843736/

Alan P. Farwell, MD. Thyroid-associated eye disease occurs in 6% of patients with Hashimoto’s Thyroiditis. American Thyroid Association’s Clinical Thyroidology For The Public. July 2016, Vol 9 Issue 7 p.11-12. Accessed at https://www.thyroid.org/patient-thyroid-information/ct-for-patients/july-2016/vol-9-issue-7-p-11-12/.