By Mayo Clinic staff
Hypothyroidism (underactive thyroid) is a condition in which your thyroid gland doesn't produce enough of certain important hormones.
Women, especially those older than age 60, are more likely to have hypothyroidism. Hypothyroidism upsets the normal balance of chemical reactions in your body. It seldom causes symptoms in the early stages, but, over time, untreated hypothyroidism can cause a number of health problems, such as obesity, joint pain, infertility and heart disease.
The good news is that accurate thyroid function tests are available to diagnose hypothyroidism, and treatment of hypothyroidism with synthetic thyroid hormone is usually simple, safe and effective once you and your doctor find the right dose for you.
By Mayo Clinic staff
The signs and symptoms of hypothyroidism vary, depending on the severity of the hormone deficiency. But in general, any problems you have tend to develop slowly, often over a number of years.
At first, you may barely notice the symptoms of hypothyroidism, such as fatigue and weight gain, or you may simply attribute them to getting older. But as your metabolism continues to slow, you may develop more obvious signs and symptoms. Hypothyroidism signs and symptom may include:
- Increased sensitivity to cold
- Dry skin
- Unexplained weight gain
- Puffy face
- Muscle weakness
- Elevated blood cholesterol level
- Muscle aches, tenderness and stiffness
- Pain, stiffness or swelling in your joints
- Heavier than normal or irregular menstrual periods
- Thinning hair
- Slowed heart rate
- Impaired memory
When hypothyroidism isn't treated, signs and symptoms can gradually become more severe. Constant stimulation of your thyroid gland to release more hormones may lead to an enlarged thyroid (goiter). In addition, you may become more forgetful, your thought processes may slow, or you may feel depressed.
Advanced hypothyroidism, known as myxedema, is rare, but when it occurs it can be life-threatening. Signs and symptoms include low blood pressure, decreased breathing, decreased body temperature, unresponsiveness and even coma. In extreme cases, myxedema can be fatal.
Hypothyroidism in infants
Although hypothyroidism most often affects middle-aged and older women, anyone can develop the condition, including infants. Initially, babies born without a thyroid gland or with a gland that doesn't work properly may have few signs and symptoms. When newborns do have problems with hypothyroidism, they may include:
- Yellowing of the skin and whites of the eyes (jaundice). In most cases, this occurs when a baby's liver can't metabolize a substance called bilirubin, which normally forms when the body recycles old or damaged red blood cells.
- Frequent choking.
- A large, protruding tongue.
- A puffy appearance to the face.
As the disease progresses, infants are likely to have trouble feeding and may fail to grow and develop normally. They may also have:
- Poor muscle tone
- Excessive sleepiness
When hypothyroidism in infants isn't treated, even mild cases can lead to severe physical and mental retardation.
Hypothyroidism in children and teens
In general, children and teens who develop hypothyroidism have the same signs and symptoms as adults do, but they may also experience:
- Poor growth, resulting in short stature
- Delayed development of permanent teeth
- Delayed puberty
- Poor mental development
When to see a doctor
See your doctor if you're feeling tired for no reason or have any of the other signs or symptoms of hypothyroidism, such as dry skin, a pale, puffy face, constipation or a hoarse voice.
You'll also need to see your doctor for periodic testing of your thyroid function if you've had previous thyroid surgery; treatment with radioactive iodine or anti-thyroid medications; or radiation therapy to your head, neck or upper chest. However, it may take years or even decades before any of these therapies or procedures result in hypothyroidism.
If you have high blood cholesterol, talk to your doctor about whether hypothyroidism may be a cause. And if you're receiving hormone therapy for hypothyroidism, schedule follow-up visits as often as your doctor recommends. Initially, it's important to make sure you're receiving the correct dose of medicine. And over time, the dose you need may change.