Hashimoto’s disease and Graves’ disease are two autoimmune disorders that affect the function of the thyroid. Hashimoto’s disease almost always causes hypothyroidism (underactive thyroid), although in rare cases, it can cause hyperthyroidism (overactive thyroid). Graves’ disease causes hyperthyroidism.
What is the thyroid gland?
The thyroid gland is a small organ located just under the skin in the neck. This bow tie-shaped organ is usually only about 5 cm across and normally can’t be felt or seen. The thyroid releases specific hormones (chemical messengers) that act on almost every tissue in the body (1). These thyroid hormones help regulate so many vital body functions, including:
- Heart rate
- Skin maintenance
- Heat production
- Rate at which calories are burned
What are autoimmune disorders?
Normally the immune system defends the body against disease and infection. But sometimes, the immune system attacks healthy cells, tissues, and organs instead. This is what is known as an autoimmune disorder or disease. When one of these disorders occurs, the attacked cells, tissues, or organs cannot function properly, and can sometimes cause life-threatening disease (2). The most well-known autoimmune disorder is type 1 diabetes, where the immune system attacks and destroys the beta cells in the pancreas, resulting in an inability to produce and secrete insulin.
What is Hashimoto’s disease?
Hashimoto’s disease is an autoimmune disorder, where the immune system produces antibodies that attack the thyroid gland. This damages the thyroid gland and it is unable to make enough thyroid hormones, resulting in hypothyroidism (underactive thyroid) (3).
Hashimoto’s disease is the most common cause of hypothyroidism, which affects about 5 in 100 Americans. It is a lot more common in women than men and usually develops in women aged 30–50 years. People who have other family members with the disease and/or have other autoimmune disorders (e.g., celiac disease, lupus, type 1 diabetes) are at increased risk of developing Hashimoto’s disease (3).
What are the symptoms and complications of Hashimoto’s disease?
Many people do not show any symptoms in the early stages of Hashimoto’s disease, but as more and more thyroid damage occurs, a range of symptoms can occur (3), including:
- Weight gain
- Constantly feeling cold
- Joint and muscle pain
- Dry skin
- Dry, thinning hair
- Irregular menstrual periods
- Fertility problems
- Slower heart rate
- Enlarged thyroid (called goiter)
Untreated hypothyroidism can cause several health problems (3), including:
- High cholesterol
- Heart disease
- High blood pressure
- Pregnancy problems
What causes Hashimoto’s disease?
In many cases, the cause of Hashimoto’s disease is unknown (3), but some factors that may play a role include:
- Genetics (as family history is common)
- Viruses (e.g., hepatitis C)
- Some medications for mental health problems
- Iodine-containing medications to treat abnormal heart rhythm
- Toxins (e.g., nuclear radiation exposure)
What is Graves’ disease?
Graves disease is also an autoimmune disorder, where the immune system produces antibodies that attack the thyroid gland. However, Graves’ disease, actually triggers the thyroid gland to produce more thyroid hormones, resulting in hyperthyroidism (overactive thyroid) (4).
Graves disease is the most common cause of hyperthyroidism, affecting about 1 in 200 Americans. Like Hashimoto’s disease, Graves’ disease is also a lot more common in women than men, usually affecting people between the ages of 30 and 50 years. People who have other family members with the disease and/or have other autoimmune disorders (e.g., celiac disease, lupus, type 1 diabetes) are at increased risk of developing Graves’ disease (4).
What are the symptoms and complications of Graves’ disease?
A range of symptoms are associated with hyperthyroidism caused by Graves’ disease (4), including:
- Weight loss
- Heat intolerance
- Muscle weakness
- Frequent bowel movements or diarrhea
- Trembling hands
- Nervousness or irritability
- Trouble sleeping
- Faster heart rate
- Enlarged thyroid (called goiter)
Untreated hyperthyroidism can cause several health problems (4), including:
- Irregular heartbeat, increasing the risk of blood clots, stroke, and heart failure
- Weakened bones and osteoporosis
- Pregnancy problems
- Graves’ ophthalmopathy (an eye disease that can cause double vision, light sensitivity, and eye pain
What causes Graves’ disease?
In Graves’ disease, the immune system produces an abnormal antibody called thyroid-stimulating immunoglobulin (TSI) that mimics the effects of the normal thyroid-stimulating hormone (TSH) and hence tells the thyroid to produce an excessive amount of thyroid hormones. But what actually triggers the immune system to produce TSI is not fully understood. It is likely a combination of genetics (as family history is common in affected people) and an outside influence like a virus (4).
How are Hashimoto’s disease and Graves’ disease diagnosed?
Medical history, physical exams, and blood tests are commonly used to diagnose thyroid issues, including Hashimoto’s disease and Graves’ disease. Blood tests may include:
- Thyroid-Stimulating Hormone (TSH): High in Hashimoto’s disease and low in Graves’ disease
- Free Thyroxine (T4): Low in Hashimoto’s disease and high in Graves’ disease
- Free Triiodothyronine (T3): Low in Hashimoto’s disease and high in Graves’ disease
- Thyroid Peroxidase Antibody (Anti-TPO): Elevated in both Hashimoto’s disease and Graves’ disease
- Thyroglobulin Antibody (Anti-Tg): Elevated in both Hashimoto’s disease and Graves’ disease
We offer each of these tests from a self-collected finger-prick blood sample. Tests are available as individual tests (links included above) or all combined together in our Thyroid Health, Complete Panel.
1. Hershnan JM. (Modified Oct 2020). Overview of the Thyroid Gland. Merck Manual Consumer Version
2. Autoimmune Diseases. (Reviewed July 2021). NIH, National Institute of Environmental Health Sciences.
3. Hashimoto’s Disease. (Reviewed June 2021). NIH, National Institute of Diabetes and Digestive and Kidney Diseases.
4. Graves’ Disease. (Reviewed Sept 2017). NIH, National Institute of Diabetes and Digestive and Kidney Diseases.