What is hyperthyroidism?

Hyperthyroidism means your thyroid gland is too active. This tiny gland is found in your neck. An overactive thyroid gland makes too much thyroid hormone. This makes your metabolism work at a faster rate.

What causes hyperthyroidism?

Hyperthyroidism has several causes.
These may include:

  • Graves’ disease. This is an autoimmune disorder. It is the most common cause of hyperthyroidism. It happens when an antibody overstimulates the thyroid. This condition is most often found in young to middle-aged women. It also tends to run in families.
  • Toxic nodular goiter. This condition
    happens when one or more lumps (nodules) of the thyroid gland become too active.
    Health experts don’t know what causes this to happen. In most cases, the nodules are
    not cancer (benign). But in rare cases the overactive thyroid tissue is cancer.
  • Thyroiditis. This occurs when the
    thyroid becomes irritated. It temporarily causes the thyroid to be overactive. The
    thyroid then often becomes underactive.

Hyperthyroidism may occur for other reasons. These include:

  • Taking too much thyroid hormone medicine to treat an underactive thyroid
  • Having too much iodine in your diet or
    in medicines, such as amiodarone
  • Having a noncancer tumor in the
    pituitary gland that makes your thyroid overactive

Who is at risk for hyperthyroidism?

These things may make it more likely for you to have hyperthyroidism:

  • You are a woman
  • You are older than age 60
  • You have had thyroid problems in the past
  • Your family has a history of thyroid problems
  • You have certain conditions, such as type 1 diabetes
  • You consume too much iodine. This can happen if you eat a lot of iodine-rich foods or take too much medicine that has this chemical.
  • You are pregnant or have had a baby in the last 6 months

What are the symptoms of hyperthyroidism?

Symptoms are different for each
person. Here are the most common ones:

  • Nervousness
  • Irritability
  • Sweating more than normal
  • Thinning of the skin
  • Fine, brittle hair
  • Weak muscles, especially in the upper
    arms and thighs
  • Shaky hands
  • Fast heartbeat (palpitations)
  • High blood pressure
  • More bowel movements than normal,
  • Weight loss
  • Trouble dealing with the heat
  • Problems sleeping
  • Prominent eyes
  • Sensitivity to bright light
  • Confusion
  • Irregular menstrual cycle in
  • Tiredness and lack of energy
  • Larger than normal thyroid gland

These symptoms may look like other health problems. Always see your healthcare provider for a diagnosis.

How is hyperthyroidism diagnosed?

Your healthcare provider will ask
about your health history. You will also need a physical exam. Other tests that can help
diagnose hyperthyroidism include:

  • Blood tests. They can measure the amount of thyroid hormone and thyroid stimulating hormone in your blood.
  • Thyroid ultrasound. This test can see if your thyroid gland has any nodules. 
  • Thyroid scan. This test uses a radioactive substance to make an image of the thyroid.