Endocrinology and Diabetes
Hyperthyroidism (Overactive Thyroid)
We help you manage an overactive thyroid at any age so you can get back to feeling like yourself.
Medically reviewed by Jose Joaquin Lado Abeal, M.D. on Nov. 19, 2024.
What Is Hyperthyroidism?
Hyperthyroidism is an overactive thyroid gland. The thyroid is a butterfly-shaped gland in your neck. It creates hormones that you need for important bodily functions.
With hyperthyroidism, the thyroid makes and releases too much thyroid hormone. The condition causes things such as your breathing, heart rate and metabolism to get faster.
In most cases, hyperthyroidism is a lifelong condition. Our endocrinologists (hormone specialists) at UC Davis Health can help you identify and control an overactive thyroid. You can find expert thyroid care in our Division of Endocrinology, Diabetes and Metabolism.
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Symptoms of a Hyperactive Thyroid
A hyperactive thyroid affects everyone differently and can cause a range of symptoms. Young adults tend to experience slightly different symptoms than older adults.
Symptoms in Children and Younger Adults
Younger people with an overactive thyroid may experience:
- Changes in your menstrual cycle
- Diarrhea
- Extreme tiredness
- Feeling nervous, anxious or shaky
- Hair loss
- Heart palpitations (a racing or skipping heart)
- Increased appetite
- Muscle weakness
- Shortness of breath
- Sweating a lot or sensitivity to heat
- Swelling in your neck
- Trouble sleeping
- Weight loss
Symptoms in Older Adults
Hyperthyroidism more commonly affects people older than 60. Older adults may experience:
- Extreme tiredness
- Feeling depressed or withdrawing from others
- Loss of appetite
- Mood changes, such as feeling agitated or having flat emotions
- Muscle weakness
- Trouble thinking or memory loss
- Weight loss
Causes of an Overactive Thyroid
Hyperthyroidism can develop at any age. Causes of an overactive thyroid range from an autoimmune disease to abnormal growths that cause too much thyroid hormone.
Graves’ Disease
Graves’ disease is an autoimmune condition. It causes your immune system to attack your thyroid, which leads to an overactive thyroid gland.
Excess Iodine
Too much iodine in your body can affect how your thyroid creates thyroid hormone.
Pituitary Tumor
The pituitary gland influences how your thyroid creates thyroid hormones. Noncancerous pituitary tumors (growths) can impact how your pituitary gland works and cause hyperthyroidism.
Pregnancy
Some people develop an overactive thyroid after pregnancy and giving birth. Postpartum hyperthyroidism usually goes away with treatment and time.
Thyroid Hormone Medication
Sometimes, medication taken to increase your thyroid hormone can raise levels too high. You may take thyroid hormone replacement medication for hypothyroidism (an underactive thyroid) or goiter (an enlarged thyroid). Your provider can adjust your medications as needed.
Thyroiditis
Thyroiditis, or inflammation (swelling) of your thyroid, can change how the gland works. It can lead to your thyroid creating too much thyroid hormone.
Thyroid Nodules
Nodules (noncancerous growths) on your thyroid can produce too much thyroid hormone.
Risk Factors for an Overactive Thyroid
Certain things increase your risk of developing an overactive thyroid, including:
Age
People older than 60 face a higher risk.
Biological Sex
Women are more likely than men to develop hyperthyroidism.
Certain Existing Conditions
Hyperthyroidism develops more often in people with diabetes, autoimmune disorders such as pernicious anemia or adrenal disorders such as Addison’s disease.
Family History
Hyperthyroidism can run in families. Having a family member with the condition can increase your risk.
High Iodine Intake
Eating large amounts of foods containing iodine can increase your risk if you have an existing thyroid issue. Foods high in iodine include seaweed, seafood, eggs, dairy products and iodized salt. Some medications also contain iodine.
Smoking
The nicotine in cigarettes can affect how your body produces thyroid hormone.
Pregnancy
Pregnancy can place you at a higher risk for hyperthyroidism that develops after pregnancy.
Diagnosis and Testing for High Thyroid Hormone
Hyperthyroidism can seriously impact your health if left undiagnosed or untreated. We work to identify the condition early and get your thyroid hormone levels under control.
Our endocrinologists do a complete evaluation to understand your symptoms and thyroid health. Your provider will do a physical exam to check for signs of an overactive thyroid and an enlarged thyroid gland. They will also review your medical history to learn about any existing conditions and medications you take.
You will likely get several blood tests. These tests are key in helping your provider diagnose hyperthyroidism, including:
- Thyroid-stimulating hormone (TSH) test: TSH is a hormone that your pituitary gland makes. It signals to your thyroid to produce thyroid hormone. A TSH test shows the amount of TSH in your blood. Low TSH suggests that your body makes too much thyroid hormone.
- Thyroxine (T4) test: This test measures the amount of a thyroid hormone called T4 in your blood.
- Triiodothyronine (T3) test: This test measures the amount of a thyroid hormone called T3 in your blood.
- Thyroid antibody test: An antibody test can help your provider check for any autoimmune diseases that may cause hyperthyroidism.
You may also get thyroid imaging and function tests, including:
- Thyroid scan and uptake: These tests check the health and function of your thyroid gland by using radioactive iodine. They can help your provider understand the cause of high thyroid hormone, such as Graves’ disease or thyroid nodules.
- Ultrasound: Your provider may use ultrasound imaging to look at thyroid nodules.
Hyperthyroidism Treatments at UC Davis Health
At UC Davis Health, you can rely on our endocrinologists for expert thyroid care. Our team prioritizes relieving your symptoms, restoring your thyroid health and helping you feel like yourself again.
We use medication, minimally invasive procedures or surgery to treat hyperthyroidism. We work with you to control your thyroid hormone and manage any side effects from treatment. Providing long-term care, we test your blood regularly for TSH or thyroid hormone to ensure treatment is working.
Our endocrinologists develop a personalized treatment plan based on the cause of an overactive thyroid and your preferences. Your provider may recommend:
Medication
Medication, including antithyroid drugs and beta blockers, can reduce your thyroid hormone levels and improve your symptoms. Typically, medication is a temporary solution for hyperthyroidism.
Radioactive Iodine (Radioiodine) Therapy
Radioiodine therapy involves swallowing small doses of radioactive iodine, which the thyroid absorbs. The radioactive iodine destroys overactive thyroid cells.
Thyroid Surgery
In some cases, your provider may recommend surgery to remove an overactive thyroid or destroy harmful cells. We offer minimally invasive thyroid procedures, including thyroid ablation, that leave minimal scars and help you recover faster. After surgery, you may need to take thyroid hormone replacement medication.
Who does it affect?
1 in 100People in the United States older than 11
Source: National Institute of Diabetes and Digestive and Kidney Diseases: Hyperthyroidism (Overactive Thyroid)
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