Hyperthyroidism

The thyroid gland finely regulates the body's metabolism. When the thyroid is overactive, too much thyroid hormone can cause fatigue, sleep problems, weight loss and digestive problems, among others.

Hyperthyroidism Overview

Reviewed: July 22, 2014
Updated: 

Hyperthyroidism is a disorder that happens when the thyroid gland makes more thyroid hormone than the body needs.

Symptoms of hyperthyroid activity can vary from person to person. Some common symptoms of hyperthyroidism are nervousness or irritability, fatigue or muscle weakness, weight loss, a fast or irregular heartbeat, and frequent bowel movements or diarrhea, among others.

Hyperthyroidism has several causes, including Graves’ disease, thyroid nodules, and thyroiditis (inflammation of the thyroid) among others. An uncommon cause is a pituitary adenoma, which is a noncancerous tumor of the pituitary gland. Graves’ disease is the most common cause of hyperthyroidism in the United States.

Treatment depends on the cause of hyperthyroidism and how severe it is. Health care providers treat hyperthyroidism with medications, radioiodine therapy, or thyroid surgery. The aim of treatment is to normalize thyroid hormone levels in order to prevent long-term complications and to resolve uncomfortable
symptoms. Medications may include beta blockers, antithyroid therapy with methimazole and propylthiouracil , and radioiodine therapy.Thyroid surgery is the least used treatment and consists the removal of part or most of the thyroid gland. 

Hyperthyroidism Symptoms

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Hyperthyroidism has many symptoms that can vary from person to person. Some common symptoms of hyperthyroidism are:
  • nervousness or irritability
  • fatigue or muscle weakness
  • heat intolerance
  • difficulty sleeping
  • hand tremors
  • fast and irregular heartbeat
  • frequent bowel movements or diarrhea
  • weight loss
  • mood swings
  • trouble concentrating
  • Increased sweating
  • Irregular menstrual periods in women
  • goiter, which is an enlarged thyroid that may cause the neck to look swollen

Eye changes. For some people with Graves' disease, the tissue behind the eyes becomes inflamed and swollen, which can cause bulging or discomfort in one or both eyes. Sometimes these eye changes may affect your vision. Eye symptoms can happen before, at the same time, or after other symptoms of Graves' disease begin. Eye problems are more common in people who smoke, and smoking may worsen eye symptoms. Eye problems often become better without treatment.

Hyperthyroidism Causes

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Hyperthyroidism has several causes, including:
  • Graves’ disease
  • Thyroid nodules
  • Thyroiditis (inflammation of the thyroid)
  • Consuming too much iodine
  • Taking large amounts of thyroid hormone
  • Some tumors of the testes or ovaries
  • Getting medical imaging tests with contrast dye that has iodine
 
It is uncommon for hyperthyroidism to be caused by a pituitary adenoma, which is a noncancerous tumor of the pituitary gland. In this case, hyperthyroidism is due to too much TSH.
 
Graves’ disease is the most common cause of hyperthyroidism in the United States. Graves' disease is an autoimmune disease that affects the thyroid. With Graves' disease, the immune system makes antibodies that act like TSH. As a result, the thyroid makes more thyroid hormone than your body needs.
 
Women are 2 to 10 times more likely than men to develop hyperthyroidism.
 
Other risk factors include:
  • previous thyroid problem, such as goiter or thyroid surgery
  • a family history of thyroid disease
  • have pernicious anemia (vitamin B12 deficiency)
  • have type 1 diabetes
  • have primary adrenal insufficiency
  • eat large amounts of food containing iodine, such as kelp
  • using iodine-containing medications such as amiodarone
  • are older than age 60
  • were pregnant or delivered a baby within the past 6 months

 

Hyperthyroidism Diagnosis

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The health care provider will take a medical history and do a physical exam.

Health care providers may use several blood tests, such as the following, to confirm a diagnosis of hyperthyroidism and to determine its cause:

  • TSH test
  • T3 and T4 test
  • Thyroid-stimulating immunoglobulin (TSI) test
  • Radioactive iodine uptake test
  • Thyroid scan

Living With Hyperthyroidism

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If you have hyperthyroidism, eat a balanced diet to obtain the necessary nutrients.

Iodine is an essential mineral for the thyroid. People with autoimmune thyroid disease may be sensitive to the harmful side
effects from iodine. Taking iodine drops or eating foods containing large amounts of iodine, such as seaweed, dulse, or kelp,
may cause or worsen hyperthyroidism.

Hyperthyroidism Treatments

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Treatment depends on the cause of hyperthyroidism and how severe it is.
 
Health care providers treat hyperthyroidism with medications, radioiodine therapy, or thyroid surgery. The aim of treatment is to normalize thyroid hormone levels in order to prevent long-term complications and to resolve uncomfortable
symptoms. A single treatment does not work for everyone and will be individualized per person.
 
Treatment will be based on your age, possible allergies or side effects of the medications, conditions such as pregnancy or heart disease, and the availability of an experienced thyroid surgeon.
 
Medications:
Beta blockers. Your doctor may prescribe a medication called a beta blocker to reduce symptoms such as tremors, rapid
heartbeat, and nervousness. Most people feel better within hours of taking these medications. These medications do not stop thyroid hormone production. Beta blockers will be given until the hyperthyroidism can be controlled.
 
Antithyroid medications. Antithyroid therapy is the easiest way to treat hyperthyroidism. Antithyroid medications include methimazole (Tapazole, Northyx) and propylthiouracil (PTU) and work by interfering with thyroid hormone production. Antithyroid medications are not used to treat thyroiditis. It may take several weeks or months for thyroid hormone levels to move into a normal range after starting these medications. You will probably be on antithyroid therapy for an average of 1 to 2 years, but treatment can continue for many years.
 

Radioiodine Therapy:

Radioactive iodine-131 is a common treatment for hyperthyroidism and has shown to be effective. Patients may need more than one round of radioiodine therapy to normalize thyroid hormone production. Majority of patients who receives radioactive iodine treatment will eventually develop hypothyroidism. However, doctors prefer this outcome, because hypothyroidism is easier to treat and has fewer long-term complications than hyperthyroidism. Those who develop hypothyroidism will then have to take synthetic thyroid hormone.
 
Thyroid Surgery:
Thyroid surgery is the least used treatment and consists the removal of part or most of the thyroid gland. Sometimes surgery may be used to treat those
•pregnant women who cannot tolerate antithyroid medications
•people with large goiters
•people who have cancerous thyroid nodules
 

Hyperthyroidism Other Treatments

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Researchers are working to better understand, prevent, and treat this disease.

National Institutes of Health (NIH) is investigating the development, signs and symptoms, and genetics of thyroid function disorders in order to further understand thyroid diseases.

Hyperthyroidism Prognosis

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If your thyroid is removed with surgery or destroyed with radiation, you will need to take thyroid hormone replacement pills for the rest of your life.

Hyperthyroidism is a treatable condition. Some causes of hyperthyroidism may even go away without treatment.

Hyperthyroidism caused by Graves disease typically may become worse over time. Hyperthyroidism caused by Graves disease is associated with several complications, some of which are severe and may affect one's quality of life.

Thyroid crisis (storm), otherwise known as thyrotoxicosis, is a sudden worsening of hyperthyroidism symptoms that may happen with infection or stress. Patients will need to be treated in the hospital.

Call your doctor if you have symptoms of hyperthyroidism. Go to an emergency room or call 911, if you notice:

  • Change in consciousness
  • Dizziness
  • Fast and/or irregular heartbeat

Call your doctor if you are being treated for hyperthyroidism and you develop symptoms of underactive thyroid, such as:

  • Depression
  • Mental and physical sluggishness
  • Weight gain
Medications:
TapazoleCytomelIopanoic AcidLiothyronineMethimazoleNorthyxFelimazolePropylthiouracil