What is hypothyroidism?

Hypothyroidism is the most common type of thyroid disorder. It means your thyroid gland is not active enough. This tiny gland is found in your neck. If the gland is underactive, it may not make enough thyroid hormone.

What causes hypothyroidism?

The most common cause of hypothyroidism is an autoimmune disorder. This means your immune system starts to attack itself. It makes antibodies against the thyroid gland. Another cause may be treatment for an overactive thyroid gland. That may include radioactive iodine therapy or surgery.

A condition called secondary hypothyroidism can also sometimes happen. It’s when your pituitary gland stops working. The pituitary gland then no longer tells the thyroid gland to make thyroid hormones.

Who is at risk for hypothyroidism?

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

  • Gender. Women are more likely than men to develop it.
  • Age. Most people with the condition are older than 60.
  • Thyroid problems or thyroid surgery in the past
  • Family history of thyroid problems
  • Certain conditions, such as type 1 diabetes and rheumatoid arthritis
  • Turner syndrome, a genetic condition that affects females
  • Pregnancy. Women who are pregnant or who have delivered a baby within the previous 6 months are more likely to get it.

What are the symptoms of hypothyroidism?

Symptoms are different for each person. They are usually hard to notice and start slowly. They may be mistaken for symptoms of depression. Here are the most common symptoms and signs:

  • Dull facial expressions
  • Tiredness (fatigue)
  • Being cold bothers you
  • Hoarse voice
  • Slow speech
  • Droopy eyelids
  • Puffy and swollen face
  • Weight gain
  • Constipation
  • Sparse, coarse, and dry hair
  • Coarse, dry, and thickened skin
  • Hand tingling or pain (carpal tunnel syndrome)
  • Slow pulse
  • Muscle cramps
  • Sides of eyebrows thin or fall out
  • Confusion
  • Increased or irregular menstrual flow in women

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

How is hypothyroidism diagnosed?

Your health care provider will ask about your past health. You will also need an exam. Blood tests can also help diagnose hypothyroidism. They can measure the amount of thyroid hormone and thyroid-stimulating hormones in your blood.

How is hypothyroidism treated?

Your health care provider will figure out the best treatment for you based on:

  • How old you are
  • Your overall health and past health
  • How sick you are
  • How well you can handle specific medicines, procedures, or therapies
  • How long the condition is expected to last
  • Your opinion or preference

The goal of treatment is to return your level of thyroid hormone back to normal. You may need to take medicine that gives you a dose of thyroid hormones. Your provider may need to change the dose over time. You will need blood tests to make sure you are taking the correct dose of thyroid hormone replacement. You will probably need to take this medicine for the rest of your life.

What are the complications of hypothyroidism?

If your hypothyroidism is not treated, these complications may happen:

  • Anemia
  • Low body temperature
  • Heart failure

When should I call my health care provider?

Tell your health care provider if your symptoms get worse or you have new symptoms. If you are a woman of childbearing age who wants to become pregnant, talk with your health care provider first.

Key points about hypothyroidism

  • Hypothyroidism means your thyroid gland is underactive. It isn’t making enough thyroid hormone. The most common cause is when your immune system starts to attack itself. It makes antibodies against the thyroid gland.
  • Symptoms include dull facial expressions, tiredness, and weight gain.
  • Blood tests can help diagnose this condition. They can measure the amount of thyroid hormone and thyroid-stimulating hormones in the blood.
  • The goal of treatment is to return your levels of thyroid hormone back to normal.
  • Untreated hypothyroidism may lead to anemia, low body temperature, and heart failure.
  • Treatment may include medicine that replaces lost thyroid hormones. You usually will need to take thyroid hormones for the rest of your life.

Next steps

Tips to help you get the most from a visit to your health care provider:
  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your provider tells you.
  • At the visit, write down the names of new medicines, treatments, or tests, and any new instructions your provider gives you.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your provider if you have questions.

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