Massachusetts General Hospital

Hyperthyroidism

What is hyperthyroidism?

Hyperthyroidism means overactivity of the thyroid gland, resulting in too much thyroid hormone in the bloodstream. The oversecretion of thyroid hormones leads to overactivity of the body's metabolism.

Thyroid Gland - Click to Enlarge

What are the symptoms of hyperthyroidism?

The following are the most common symptoms of hyperthyroidism. However, each individual may experience symptoms differently. Symptoms may include:

• Nervousness

• Irritability

• Increased perspiration

• Thinning of the skin

• Fine, brittle hair

• Weak muscles, especially in the upper arms and thighs

• Shaky hands

• Fast heartbeat

• High blood pressure

• Increased bowel movements

• Weight loss

• Sleeping difficulty

• Prominent eyes

• Sensitivity to bright light

• Confusion

• Irregular menstrual cycle

The symptoms of hyperthyroidism may resemble other conditions or medical problems. Always consult your doctor for a diagnosis.

Types of hyperthyroidism

There are several forms of hyperthyroidism, including:

• Graves' disease (diffuse toxic goiter). Graves' disease is most often associated with hyperthyroidism. Researchers believe Graves' disease is caused by an antibody which stimulates the thyroid too much. This overstimulation causes the excess production of thyroid hormone. Graves' disease is categorized as an autoimmune disorder (a dysfunction of the body's immune system). The disease is most common in young to middle-aged women and tends to run in families.
  
  Symptoms of Graves' disease are identical to hyperthyroidism, with the addition of three other symptoms. However, each individual may experience symptoms differently. The three additional symptoms include:

  • Goiter (enlarged thyroid which may cause a bulge in the neck)

  • Bulging eyes (exophthalmos)

  • Thickened skin over the shin area

• Toxic nodular goiter (also called multinodular goiter). Hyperthyroidism caused by toxic nodular goiter is a condition in which one or more nodules of the thyroid becomes overactive. The overactive nodules actually act as benign thyroid tumors. Symptoms of toxic nodular goiter do not include bulging eyes or skin problems, as in Graves' disease. The cause of toxic nodular goiter is not known.

• Thyroiditis. Thyroiditis causes temporary hyperthyroidism, usually followed with hypothyroidism (an underactive thyroid). Thyroiditis is an inflammation of the thyroid gland. There are three types of thyroiditis:

  • Hashimoto's thyroiditis

  • Subacute granulomatous thyroiditis

  • Silent lymphocytic thyroiditis

  In addition, if a person takes too many thyroid hormone tablets, hyperthyroidism may occur.

How is hyperthyroidism diagnosed?

In addition to a complete medical history and medical examination, diagnostic procedures for hyperthyroidism may include:

• Measurement of thyroid hormone in the bloodstream

• Thyroid ultrasound.  A test to evaluate the thyroid gland for evidence of any nodules. 

• Thyroid scan. A test that uses a radioactive substance to create an image of the thyroid.

Treatment for hyperthyroidism

Treatment for hyperthyroidism is very specific for each patient. The goal of treatment is to restore the thyroid gland to normal function, producing normal levels of thyroid hormone. Specific treatment for hyperthyroidism will be determined by your doctor based on:

• Your age, overall health, and medical history

• Type of hyperthyroidism

• Extent of the disease

• Your tolerance for specific medications, procedures, or therapies

• Expectations for the course of the disease

• Your opinion or preference

Treatment may include:

• Use of antithyroid drugs that help lower the level of thyroid hormones in the blood.

• Use of radioactive iodine, in the form of a pill or liquid, which damages thyroid cells so that production of thyroid hormones is slowed down.

• Surgery to remove part of the thyroid (the overactive nodule).

• Use of beta-blocking agents, which block the action of thyroid hormone on the body; (These drugs do not change the levels of thyroid hormone in the blood, but may make the patient feel better.)