What is Graves' Disease?
Reviewed by: HU Medical Review Board | Last reviewed: October 2021 | Last updated: May 2023
Graves’ disease is an autoimmune disease that affects 1 out of every 200 people in the United States. Autoimmune diseases result when the body cannot tell the difference between harmful invaders and healthy cells and tissue. As a result, the immune system attacks healthy cells and tissue, damaging or destroying them. Graves’ disease is the most common cause of overactive thyroid (hyperthyroidism).1,2
In Graves’ disease, abnormal immune cells attack the thyroid gland. The thyroid responds by making an excess amount of thyroid hormone. Too much thyroid hormone leads to an overactive thyroid.1,2
Up to half of those with Graves’ disease develop thyroid eye disease (TED). Despite their similarities, TED and Graves’ disease are different conditions requiring separate treatments.1-3
Because thyroid hormones affect different areas of the body, the symptoms of Graves’ disease vary from person to person. Since Graves’ disease results in an increased metabolism, symptoms relate to increased or excessive function, including:4
- Irritability or anxiety
- Rapid heartbeat
- Increased blood pressure
- Profuse sweating
- Trembling or shaking of the hands or fingers (fine tremor)
- Enlarged thyroid gland (goiter)
- Abnormal menstruation
- Increased number of bowel movements
- Weight loss
- Intolerance to heat
- Hair loss or changes to hair quality
- Reddening and thickening of the skin on the shins or top of the feet (uncommon)
Up to 5 out of every 10 people with Graves’ disease develop TED. Symptoms of TED include:5
- Bulging of the eyes
- Puffy eyelids
- Red, irritated, and painful eyes
- Dry, gritty eyes
- Watery eyes
- Blurred vision
- Problems seeing different colors
- Double vision
Doctors do not know what causes autoimmune diseases like Graves’ disease.4
A gland in your brain known as the pituitary gland makes and releases a hormone called thyroid stimulating hormone (TSH). TSH tells the thyroid how much thyroid hormones (known as T3 and T4) to make. If T3 and T4 levels drop too low, the pituitary gland produces TSH. In turn, more thyroid hormones are made by the thyroid gland.1,2
Graves’ disease involves a harmful antibody called thyroid stimulating immunoglobulin (TSI). TSI mimics TSH, tricking the body into thinking it needs to make more thyroid hormones. The result is excess thyroid hormones, which leads to hyperthyroidism.1,2
TSI attacks the healthy cells and proteins of the thyroid. The tissues and cells around your eyes are similar to those found in the thyroid. This may explain why some people with Graves’ disease develop symptoms of TED.1,2
Your doctor will perform a full exam to check for signs and symptoms of Graves’ disease. Your past medical history and family health history are important, and your doctor will discuss these also with you. Your doctor may order a variety of tests to diagnosis Graves' disease.6
Blood tests will be ordered to check your thyroid hormone levels. These tests will look for and measure levels of:6,7
- Thyroid-stimulating hormone (TSH), which is typically low in Graves’ disease.
- Triiodothyronine (T3) and thyroxine (T4), which are hormones made in the thyroid but controlled by the pituitary gland in the brain. These are both typically high in those with Graves’ disease, indicating hyperthyroidism.
- Thyroid-stimulating immunoglobulin (TSI), the antibody present in those with Graves’ disease. A positive result proves Graves’ disease.
- Thyroid stimulating hormone receptor antibody (TRAb), another harmful antibody that may or may not be present in those with Graves’ disease.
- Anti-thyroid peroxidase antibody (anti-TPO), another harmful antibody that is usually found in those with Graves’ disease. This antibody is also found in those with Hashimoto’s disease, an autoimmune thyroid disease that leads to low thyroid function (hypothyroidism).
Ultrasounds create images of body parts using high-frequency radio waves. In Graves’ disease, the thyroid may or may not be enlarged.6
Radioactive iodine uptake and thyroid scan
A radioactive iodine uptake test (RAIU) measures the function of the thyroid gland. A small amount of radioactive iodine is given in a pill that is swallowed. The iodine collects on the thyroid. After some time, a special probe is used to scan the thyroid and measure the amount of iodine taken up by the thyroid.6,8
The RAIU is often used with a thyroid scan, which uses a special camera to view the size, shape, and position of the thyroid.6
Your doctor may order additional imaging tests if other tests do not provide a diagnosis. These may include CT scans or MRI imaging.6
For those with Graves’ disease who develop symptoms of TED, it is important to understand that treatment for both conditions is different. Graves’ and TED can occur together or separately, but neither causes the other.9
The goals for Graves’ disease treatment include:6
- Stopping the production and release of excess thyroid hormones
- Blocking the negative effects of thyroid hormones
Radioactive iodine therapy
With this therapy, radioactive iodine is given by pill. Once swallowed, the iodine deposits in the thyroid. The radiation destroys the overactive thyroid cells. This therapy is also known as radioiodine therapy.6
Radioiodine therapy can increase the risk of new or worsened symptoms of TED. Talk to your doctor about this treatment, including the risks and benefits.6
Anti-thyroid drugs interfere with the thyroid’s ability to use iodine in order to make hormones. These drugs include:6
- TapazoleⓇ (methimazole)
These drugs block the effect of hormones on the body. These drugs treat other conditions like high blood pressure. If you have other conditions, such as asthma, your doctor might make certain adjustments with the type of beta blocker prescribed.6
Some people with Graves’ disease need surgery to remove part or all of their thyroid gland. This is called subtotal thyroidectomy or total thyroidectomy. After surgery, replacement of thyroid hormones is usually needed.6
Because Graves’ disease is common in those with thyroid eye disease, understanding Graves’ disease might help you better understand TED. Keep in mind, both TED and Graves’ are different diseases. Talk to your doctor about your condition, symptoms, and best treatments available to you.