It's estimated that about 3 million people in the U.S. suffer from hyperthyroidism. The vast majority of sufferers are women.
Causes of HyperthyroidismThe most common cause of hyperthyroidism is Graves' disease. In Graves' disease, antibodies target the thyroid gland, causing it to overproduce thyroid hormone.
While Graves' disease is by far the most common cause for hyperthyroidism, some other causes of an overactive thyroid include nodules, various forms of thyroiditis, the autoimmune condition Hashimoto's disease, a temporary hyperthyroidism that affects women with severe morning sickness, iodine exposure, and other factors.
Risks and Symptoms of Graves' Disease/HyperthyroidismThe risk factors for development of hyperthyroidism or Graves' disease include personal or family history of thyroid or autoimmune disease, recent pregnancy, and exposure to iodine, among other factors.
Some of the key risk factors and triggers for Graves' disease and hyperthyroidism include:
- Female gender
- Personal and family history of thyroid problems, autoimmune disease, or endocrine disease
- Age 20 and 40
- Pregnancy -- During pregnancy and the year after childbirth
- Current or former smoker
- Excessive intake of thyroid hormone
- Exposure to or excess of iodine/iodine drugs
- Certain medical treatments
- Trauma to the thyroid
- Recently experienced major life stress
- Holistic and nutritional factors
- Goiter, thyroid enlargement, neck sensations
- Weight and appetite changes
- Pregnancy-related problems
- Feeling warm all the time, sweating, thirst, fever
- Heart and blood pressure changes, fast heart rate, abnormal heart rhythms
- Bowel problems, diarrhea
- Fatigue, exhaustion
- Muscle and join pain and fatigue
- Skin changes, blister-like bumps on the forehead and face, hives, itching, vitiligo.
- Skin patches on the shins and legs (Graves' dermopathy/ pretibial myxedema)
- Hair loss and other hair changes
- Finger/nail changes, including swollen, wider fingertips and separation of nail bed from skin
- Eye problems, including bulging, dryness, pain, redness, puffiness
- Thinking/cognition problems, including difficult concentrating or making decisions, memory problems, and racing thoughts.
- Changes to mood and feelings, including depression, mood swings, uncontrollable anger, irrational anger
- Panic and anxiety, panic attacks
- Fast reflexes, startling, tremors
Risks and symptoms of are all discussed at length in the article on the Symptoms of Graves' Disease/Hyperthyroidism.
In addition, a checklist of symptoms and risks is featured in the Hyperthyroidism Risks/Symptoms Checklist. To pinpoint symptoms of an overactive thyroid, you may also want to take this interactive online quiz: Could You Be Hyperthyroid?
Diagnosing Graves' Disease and HyperthyroidismDiagnosing hyperthyroidism requires a complete clinical evaluation, during which the doctor examines the patient and the thyroid.
The clinical exam includes the doctor feeling and listening to the neck, evaluating reflexes, heart rate, heart rhythm, blood pressure, weight, body temperature, and looking for possible clinical signs of hyperthyroidism, including flushing, blister-like bumps of the forehead and face, vitiligo (loss of skin pigmentation), unusually smooth skin, hives, acne, hair loss, tremors, swollen fingertips separation of fingernail from the underlying nail bed, lesions on the shins, and eye problems such as bulging or lid lag.
Hyperthyroidism can usually be confirmed by use of the TSH, T4 (or Free T4), T3 (or Free T3) and Radioactive Iodine Update (RAI-U) tests. In hyperthyroidism, test results that confirm hyperthyroidism include:
- TSH Test -- usually below normal, to undetectable
- T4/Free T4 Test -- Normal to High
- T3/Free T3 Test -- Normal to High
The Radioactive Iodine Update (RAI-U) test, which visualizes the thyroid and its ability to absorb iodine, is also used to diagnose hyperthyroidism, and help determine whether the hyperthyroidism was caused by Graves' disease.
Read more about Thyroid Imaging Tests.
Diagnosing Graves' disease also frequently involves evidence of elevated Thyroid Receptor Antibodies (TRAb) / Thyroid-Stimulating Immunoglobulins (TSI).
A comprehensive overview of how Graves' disease and hyperthyroidism is diagnosed is featured in this article: Diagnosis of Graves' Disease/Hyperthyroidism.