Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone. This condition is often called underactive thyroid.
Myxedema; Adult hypothyroidism
The thyroid gland is an important organ of the
Hypothyroidism is more common in women and people over age 50.
The most common cause of hypothyroidism is thyroiditis. Swelling and inflammation damage the thyroid gland’s cells.
Causes of this problem include:
The immune system attacking the thyroid gland
Viral infections (common cold) or other respiratory infections
Pregnancy (often called postpartum thyroiditis)
Other causes of hypothyroidism include:
- Certain medicines, such as lithium and amiodarone
- Congenital (birth) defects
- Radiation treatments to the neck or brain to treat different cancers
- Radioactive iodine used to treat an overactive thyroid gland
- Surgical removal of part or all of the thyroid gland
Sheehan syndrome, a condition that may occur in a woman who bleeds severely during pregnancy or childbirth and causes the destruction of the pituitary gland Pituitary tumoror pituitary surgery
Hard stools or constipation
Increased sensitivity to cold temperature
Fatigue or feeling slowed down
Heavier and irregular menstrual periods
Joint or muscle pain
Paleness or dry skin
Sadness or depression
Thin, brittle hair or fingernails Weakness Weight gain
Late symptoms, if untreated:
- Decreased taste and smell
- Puffy face, hands, and feet
- Slow speech
- Thickening of the skin
- Thinning of eyebrows
Exams and Tests
The health care provider will do a
Coarse features of the face
Pale or dry skin, which may be cool to the touch
Swelling of the arms and legs
Thin and brittle hair
Blood tests are also ordered to measure your thyroid hormones
You may also have tests to check:
- Cholesterol levels
- Complete blood count (
- Liver enzymes
Treatment is aimed at replacing the thyroid hormone that you are lacking.
Levothyroxine is the most commonly used medicine:
- You will be prescribed the lowest dose possible that relieves your symptoms and brings your blood hormone levels back to normal.
- If you have heart disease or you are older, your doctor may start you on a very small dose.
- Most people with an underactive thyroid will need to take this medicine for life.
When starting your medicine, your doctor may check your hormone levels every 2 to 3 months. After that, your thyroid hormone levels should be monitored at least once every year.
When you are taking thyroid medicine, be aware of the following:
Do not stop taking the medicine when you feel better. Continue taking it exactly as your doctor prescribed.
If you change brands of thyroid medicine, let your doctor know. Your levels may need to be checked.
What you eat can change the way your body absorbs thyroid medicine. Talk with your doctor if you are eating a lot of soy products or are on a high-fiber diet.
Thyroid medicine works best on an empty stomach and when taken 1 hour before any other medications. Ask your doctor if you should take your medicine at bedtime. Studies have found that taking it at bedtime may allow your body to absorb the medicine better than taking it in the daytime.
Wait at least 4 hours after taking thyroid hormone before you take fiber supplements, calcium, iron, multivitamins, aluminum hydroxide antacids, colestipol, or medicines that bind bile acids.
While you are taking thyroid replacement therapy, tell your doctor if you have any symptoms that suggest your dose is too high, such as:
Rapid weight loss
Restlessness or shakiness
In most cases, thyroid hormone levels return to normal with proper treatment. You will likely take a thyroid hormone medicine for the rest of your life.
Myxedema coma, the most severe form of hypothyroidism, is rare. It occurs when thyroid hormone levels get very low. It can be caused by an infection, illness, exposure to cold, or certain medicines in people with untreated hypothyroidism.
Myxedema coma is a medical emergency that must be treated in the hospital. Some patients may need oxygen, breathing assistance (ventilator), fluid replacement and intensive-care nursing.
Symptoms and signs of myxedema coma include:
Below normal temperature
Low blood pressure
Low blood sugar
- Inappropriate or uncharacteristic moods
People with untreated hypothyroidism are at increased risk of:
Infertility, miscarriage, giving birth to a baby with birth defects
- Heart disease because of higher levels of LDL (“bad”) cholesterol
- Heart failure
When to Contact a Medical Professional
Call your health care provider if you have symptoms of hypothyroidism (or myxedema).
If you are being treated for hypothyroidism, call your doctor if:
chest painor rapid heartbeat
You have an infection
Your symptoms get worse or do not improve with treatment
You develop new symptoms
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