What is hypothyroidism?
Hypothyroidism is known as underactive thyroid. It occurs when your thyroid gland does not make enough thyroid hormone. It means you have low thyroid activity. The thyroid gland is shaped like a butterfly. It is located in the front of your neck, below your Adam’s apple. The thyroid controls your metabolism. It makes hormones that control how well you burn calories, your heart rate, your muscles, bones, and other organs.
Symptoms of hypothyroidism
Hypothyroidism often begins slowly. Symptoms can be mistaken for stress, depression, or other health problems. Common symptoms include:
- Unplanned weight gain.
- Muscle weakness.
- Muscle aches, cramps, tenderness, or stiffness.
- Increased sensitivity to cold.
- Pale, dry skin.
- Puffy face.
- Hoarse voice.
- Joint pain, stiffness, or swelling.
- Changes in menstrual patterns, such as heavier flow.
- An enlarged thyroid gland (called a goiter), which can appear as swelling at the base of the neck.
- Brittle hair and fingernails.
- Forgetfulness or confusion.
Anyone can have an underactive thyroid. This includes infants and teenagers. Babies who are born without a thyroid gland or with a thyroid that doesn’t work may not have many symptoms at first. They may have yellowing of the skin and yellowing of the whites of their eyes (jaundice). Their face could be puffy and their tongue may be enlarged causing choking. As the disease progresses, infants can have trouble feeding and may not grow and develop normally. They also may be constipated, sleepy, and have poor muscle tone. If it is not treated, hypothyroidism in infants can lead to physical and an intellectual disability. In the United States, newborn infants are screened for hypothyroidism before leaving the hospital.
Kids and teens who have hypothyroidism have the same symptoms as adults. In addition, they could have:
- Slow growth.
- Slow mental development.
- Delayed permanent teeth.
- Delayed puberty.
What causes hypothyroidism?
The most common cause of hypothyroidism is an autoimmune disorder called Hashimoto’s disease. Normally, the immune system helps protect the body against viruses, bacteria, and other substances. An autoimmune disease causes it to attack your body’s tissues and/or organs. With Hashimoto’s, the immune system attacks the thyroid and keeps it from producing enough hormones.
Other common causes of hypothyroidism include:
- Certain medicines.
- Radiation therapy.
- Thyroid surgery.
- Treatment for hyperthyroidism (overactive thyroid).
Some less common causes of hypothyroidism include:
- Congenital disease. About 1 in 3,000 infants in the United States are born with a defective thyroid or no thyroid at all.
- Pituitary disorder. The pituitary gland produces a thyroid-stimulating hormone (TSH). This tells the thyroid gland how much thyroid hormone to produce. A pituitary disorder may keep the pituitary gland from producing the right amount of TSH to manage thyroid hormones.
- Some women have hypothyroidism during or after pregnancy. This is because their bodies produce antibodies that attack the thyroid gland. If not treated, hypothyroidism can be harmful to both mother and baby.
- Iodine deficiency. Iodine is a mineral used by the body to make thyroid hormones. A lack of iodine can keep your thyroid from producing enough hormones. In the United States, table salt has iodine added to it to make sure everyone gets enough.
How is hypothyroidism diagnosed?
Contact your doctor if you have symptoms of an underactive thyroid. He or she will do a blood test to measure the amount of thyroid hormone and TSH in your blood. This confirms the diagnosis.
Some doctors recommend screening older women for hypothyroidism during routine physical exams. Some also recommend screening women who are pregnant or trying to become pregnant. This is because low amounts of the thyroid hormone can play a role in infertility.
Can hypothyroidism be prevented or avoided?
There is no known way to prevent hypothyroidism. It is more common in women than men, especially those older than 60 years of age. You also are at greater risk if you:
- Have a family history of thyroid disease.
- Have been treated with radioactive iodine or anti-thyroid medicines.
- Have received radiation therapy to your neck or upper chest.
- Have had thyroid surgery.
Treatment for hypothyroidism is a replacement thyroid hormone. You take the supplement daily in pill form. This medicine regulates your hormone levels and helps relieve symptoms. Over time, your metabolism goes back to normal. The medicine helps to lower your LDL cholesterol and may reverse some weight gain.
The correct medicine dose varies for each person. It may take a few tries to get the right dose. If you don’t take enough, you may continue to have symptoms of hypothyroidism. If you take too much, you may have symptoms similar to those of hyperthyroidism. Your doctor can tell how much to give based on your symptoms, blood test results, and the cause.
Some medicines and foods affect your body’s ability to absorb the replacement thyroid hormone. Examples of medicine are iron supplements, calcium supplements, cholestyramine, and aluminum hydroxide (found in some antacids). Tell your doctor if you eat large amounts of soy products or are on a high-fiber diet.
Living with hypothyroidism
If it is not treated, hypothyroidism can lead to other health problems. These include:
- A goiter. It is common to have an enlarged thyroid. This can cause a swollen lump on your neck called a goiter. A goiter can affect your appearance and can even make it hard for you to swallow or eat.
- Obesity. Weight gain is common in people who have underactive thyroid. This is because your hormone levels affect your metabolism. Diet and exercise can help manage your weight.
- Heart disease. An underactive thyroid causes high levels of “bad” (LDL) cholesterol.
- Mental health issues. Depression that occurs with hypothyroidism can worsen over time.
- Myxedema. This is a rare, life-threatening condition. Symptoms are intense sensitivity to cold and drowsiness or severe lethargy. This can lead to unconsciousness and a coma. See a doctor right away if you notice these warning signs.
- Birth defects. Babies who are born to women who have untreated hypothyroidism can have birth defects.
- Infertility. Not enough thyroid hormone can make it hard for some women to get pregnant. An underactive thyroid also can be harmful to the mother and baby during pregnancy. Most doctors test women’s thyroid hormone levels at this stage.
Questions to ask your doctor
- What is the cause of my hypothyroidism?
- Do I have Hashimoto’s disease?
- What are the results of my blood test and what do the results mean?
- How long will I need to take medicine? What are the side effects?
- Are there any lifestyle changes I can make to relieve my symptoms?
- Am I at risk for related health problems?
Copyright © American Academy of Family Physicians
This information provides a general overview and may not apply to everyone. Talk to your family doctor to find out if this information applies to you and to get more information on this subject.