The thyroid gland is a butterfly-shaped gland in the front of the neck. It produces hormones that control metabolism. Hyperthyroidism occurs when the thyroid gland becomes overactive and produces too much thyroid hormone.
The Thyroid Gland
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Causes
Hyperthyroidism may be caused by:
Graves disease—an autoimmune disorder that occurs when the immune system produces antibodies that attack cells of the thyroid gland
Thyroid nodules:
Toxic uninodular goiter—a single area/nodule in the thyroid gland is overactive
Toxic multinodular goiter—multiple nodules in the thyroid gland which overproduce thyroid hormone
Thyroiditis—inflammation of the thyroid that may later lead to hypothyroidism
Taking too much thyroid hormone—very rarely from meat sources contaminated by animal thyroid glands
Risk Factors
Factors that may increase your chance of hyperthyroidism include:
Pregnancy—postpartum thyroiditis (hyperthyroidism followed by hypothyroidism)
Family history of Graves disease
Certain viral infections
Smoking
Symptoms
Symptoms come on slowly. As the thyroid becomes more overactive, symptoms may appear.
Hyperthyroidism may cause:
Heart palpitations—more common in people over 50 years old
Rapid or irregular pulse
Shortness of breath
Fatigue
Heat intolerance
Itchiness
Nervousness, restlessness, or irritability
Difficulty sleeping
Increased number of bowel movements/diarrhea
Irregular or no menstrual periods
Unexplained weight loss despite an increased appetite
Increased sweating
Tremors
Double vision
Lumpy, red thickening of the skin in front of the shins
Diagnosis
You will be asked about your symptoms and medical history. A physical exam will be done.
Tests may include:
Blood tests to measure level of thyroid hormones and look for thyroid antibodies
Radioactive iodine uptake test to measure how much iodine the thyroid gland absorbs over the course of several hours
Treatment
Treatment will depend what is causing the hyperthyroidism. It will also be adjusted if you are pregnant. Talk to your doctor about the best treatment options for you.
Options include:
Antithyroid Drugs
Antithyroid medications work best for Graves disease. They will reduce thyroid activity. Smoking can interfere with some of the medications. If you smoke, talk to your doctor about how you can successfully quit.
All theses medications can cause a rash, fever and painful joints. Serious adverse reactions include increased risk of infection and liver damage.
If the disease goes into remission, you may no longer need medication.
Beta-Blockers
This type of medication can relieve rapid heart rate and nervousness.
Radioactive Iodine
Radioactive iodine is taken orally. It is then absorbed by the thyroid gland. Once there, it damages most of the thyroid cells. These cells can no longer produce thyroid hormones. Within days, the excess iodine passes out of the body in the urine or changes into a nonradioactive state. This treatment reduces the activity of the thyroid. Sometimes the treatment can decrease the thyroid levels too much. In this case, you will need to take a daily thyroid hormone replacement.
Surgery
Thyroidectomy is uncommon for the treatment of hyperthyroidism. It will remove part or all of the thyroid. It may be an option when medical therapy fails.
After a thyroidectomy, you may need to take daily thyroid, calcium, or vitamin D supplements.
Eye Protection
If there are eye symptoms like dry red eyes or double vision, your doctor may prescribe:
Eye protection before sleep
Artificial tears
Sunglasses
You may be referred to an eye specialist.
Prevention
There are no current guidelines to prevent hyperthyroidism.