Hypothyroidism is a condition in which the thyroid gland does not make enough thyroid hormone. Too little hormone slows down chemical reactions in the body. This slowdown causes mental and physical changes.
The thyroid gland is located in the lower front of the neck. This gland takes iodine from the food you eat to make hormones called thyroxine (T4) and triiodothyronine (T3). The hormones control your metabolism (the chemical processes your body uses to turn the food you eat into energy). You need thyroid hormones to control body temperature, heart rate, appetite, and digestion. If you have too little hormone, you may gain weight, your body temperature may get lower, and you may feel tired or sluggish.
Some of the more common causes of hypothyroidism are:
Anyone can have hypothyroidism, but it happens most often in women over age 40. Some thyroid problems are inherited. Some are present at birth.
The slowing of your body's processes can take months or even years. This can make it hard to know that this disease is causing your problems.
Symptoms of hypothyroidism include:
A condition that develops after several years of untreated hypothyroidism is called myxedema. Myxedema can cause you to feel cold, be slow to talk and move, be less mentally alert, and possibly feel drowsy much of the time. You can even fall into a coma.
Your healthcare provider will ask about your symptoms and examine you. Blood tests can measure the levels of thyroid hormone. They can also measure thyroid-stimulating hormone (TSH) made by your pituitary gland. TSH causes your thyroid gland to make thyroid hormone.
Your healthcare provider will prescribe synthetic thyroid hormone medicine. You will most likely need to take the medicine every day for the rest of your life.
Most people need only small doses of the thyroid medicine. After starting treatment, you will have more blood tests to be sure you are taking the right amount of thyroid hormone. It may take several weeks to find the right dosage for you. Once the correct dosage is found, your thyroid hormone level will need to be checked every few months.
If you have coronary artery disease or are at risk for it, your provider will prescribe a smaller dose of hormone at first. Replacing thyroid hormone too quickly can be hard on your heart. In some cases it can trigger a heart attack. Taking too much thyroid hormone can also cause osteoporosis.
For all of these reasons your thyroid hormone blood level will be checked for the rest of your life to make sure it is in the correct, normal range.
Usually hypothyroidism starts getting better within a week after you start hormone therapy. All symptoms go away in a few weeks. In most cases, however, you must continue this treatment for the rest of your life.
Mild hypothyroidism may cause no symptoms. Without treatment, however, the disease can become disabling over time. Untreated hypothyroidism may cause the following problems:
If the cause of hypothyroidism is thyroiditis and it is not treated, your thyroid gland may swell. This swelling, called a goiter, may cause a big bulge in your neck.
If you are an older adult with hypothyroidism, you may not get medical treatment because you don't know you have a problem that can be treated. You may think your symptoms are just part of aging. If you have symptoms such as tiredness, muscle weakness, dry skin, depression, feeling cold, and constipation, see your healthcare provider.
When you have hypothyroidism, be sure to:
In most cases hypothyroidism cannot be prevented.