There are more than 20 million Americans with thyroid disease and most are unaware they have the disease. Your thyroid gland is a tiny, butterfly-shaped gland that’s located in front of your windpipe. While it weighs only an ounce, this gland is the command center for many organs in your body, including your heart, brain and liver. As such, the thyroid gland is responsible for regulating metabolism and cell growth. The symptoms of thyroid disorders are often difficult to read, for both the woman affected and her physician. In fact, many women don’t even know they have a thyroid problem. If left untreated, thyroid disease can cause serious health problems.
Thyroid disease affects the production of thyroid hormones. Hypothyroidism results from an underactive gland that produces insufficient thyroid hormones. In hyperthyroidism, the opposite is true. As you will read below, each disorder has unique causes, symptoms and treatments.
Hypothyroidism Causes Symptoms and Treatments Photo Gallery
Hypothyroidism develops when your thyroid gland does not produce enough thyroid hormones to meet your body’s needs. An underactive thyroid gland will cause your metabolic rate to slow down, making you feel slow, sluggish and constantly tired. Thyroid deficiencies have also been known to cause infertility or miscarriages in early pregnancy.
Hypothyroidism affects ten times more women than men. It usually strikes after age 40 and is common in elderly women. Hypothyroidism usually develops when your body’s immune system malfunctions, causing damage to the thyroid gland. It can also occur after treatment for hyperthyroidism, an overactive thyroid. In most cases, hypothyroidism is a permanent condition that requires lifelong treatment with thyroid hormone drugs.
WHAT CAUSES HYPOTHYROIDISM?
The thyroid gland is a small organ with a big job. Located in your neck, just below your Adam’s apple, the thyroid controls and coordinates your body’s main body functions, or metabolism. It produces two thyroid hormones, thyroxine (T4) and triiodothyronine (T3), which circulate through your bloodstream and act on almost every organ in your body. These hormones maintain a healthy metabolic rate by controlling the speed at which your body burns calories to use energy.
A well-functioning thyroid gland is essential to normal growth and development. If your thyroid does not produce enough thyroid hormones, all your bodily functions will slow down. You will begin to feel sluggish and tired and may develop a variety of other uncomfortable symptoms. As the condition becomes more advanced, you could experience serious health problems.
The most common type of hypothyroidism is known as Hashimoto’s thyroiditis or chronic thyroiditis. It is an auto-immune disease, caused by a malfunction of your immune system. In this case, the immune system begins to produce anti-thyroid antibodies that attack your thyroid gland. The damage caused by these antibodies prevents the thyroid from producing adequate levels of thyroid hormones. People with Hashimoto’s thyroiditis often develop a painless thyroid lump or goiter that can be seen at the lower front of their throat.
Hypothyroidism can also be caused by
• surgery to remove the thyroid gland (usually a treatment for thyroid cancer, in some cases for overactive thyroid)
• radioactive iodine therapy (usually used to treat overactive thyroid conditions)
• x-rays, especially of the head and neck
• treatment with certain medications, such as lithium
• pregnancy and postpartum conditions
• iodine deficiencies
• absence of a thyroid gland at birth (all babies in the United States are screened for hypothyroidism to detect this condition)
• having a genetic predisposition
Another version of the disorder, known as secondary hypothyroidism, may develop if you have an abnormality in an area of your brain called the hypothalamic-pituitary axis. The pituitary gland helps the thyroid gland regulate the production of T3 and T4 by releasing thyroid-stimulating hormone (TSH). The hypothalamus gland performs a similar function by producing thyrotropin-releasing hormone (TRH). If these two glands do not secrete enough hormones to trigger your thyroid gland to function, you may experience the hormonal deficiencies that lead to hypothyroidism.
The symptoms of hypothyroidism vary in severity, depending on the decrease in thyroid hormone levels and the length of time that a deficiency has been present. Most of the time, the symptoms are fairly mild. In the early stages of the disorder, symptoms may not be noticeable at all and you may still feel quite well. However, research indicates that people with mild hypothyroidism go on to develop more severe thyroid problems in later years.
When you have more severe hypothyroidism, you may begin to feel slow, sluggish, tired and run down. You may also feel depressed and lose interest in your normal activities. Additional hypothyroid symptoms include
• increased sensitivity to cold
• muscle swelling or cramps, especially in your arms and legs
• weight gain
• dry, itchy skin
• increased menstrual flow
• tingling or numbness in your hands and feet
• coarseness or loss of hair
• memory loss and mental impairment
• infertility or miscarriages
• a slow heart rate
• dull facial expression, droopy eyelids and hoarse voice
• high blood pressure
Naturally, you won’t develop all of these symptoms, but you can certainly expect to experience some of them. Because hypothyroidism progresses gradually, worsening over a period of months or years, you may not even realize how unwell you feel until your thyroid condition is corrected with hormone medication.
WHO’S AT RISK?
Hypothyroidism is a fairly common condition that affects almost 5 percent of the population. More than 5 million Americans have an underactive thyroid gland. Although thyroid disease can affect anyone, statistics indicate that hypothyroidism is 10 times more common in women than in men. This comes as no surprise, since research has shown that 75 percent of all auto-immune diseases occur in women. To underline the high prevalence of this disease in women, consider the fact that Hashimoto’s thyroiditis, the most common form of hypothyroidism, strikes women as much as 50 times more often than men.
The risk of hypothyroidism increases considerably as you age. The condition is so common in postmenopausal women that up to 10 percent of women over the age of 65 show evidence of hypothyroidism.
It also seems that auto-immune diseases, such as Hashimoto’s thyroiditis, have been associated with a genetic component. Research indicates that this particular type of hypothyroidism clusters in families, so your risk may be greater if you have a close female relative with a related auto-immune disease.
Some women also develop thyroid conditions during or immediately after pregnancy. Some type of thyroid dysfunction complicates approximately 5 to 9 percent of all pregnancies. Thyroiditis is especially common during the period of time following the birth of the baby, when the condition can often be confused with postpartum depression.
For reasons that are still unknown, one out of every 4000 infants is born without a working thyroid gland, a condition known as congenital hypothyroidism. If undetected, this disorder can cause mental retardation and serious growth defects. Fortunately, it has been virtually eliminated in North America, where all babies are tested for the condition at birth.
If you have had surgery or received radioactive iodine therapy to treat thyroid conditions such as hyperthyroidism, Graves’ disease or thyroid cancer, then you may be predisposed to hypothyroidism. Irradiation of the head and neck through x-rays or cancer treatment may also predispose you to thyroid problems.
In countries outside of North America, one of the most common causes of hypothyroidism is iodine deficiency. Tiny amounts of this mineral are essential components of the thyroid hormones, and the thyroid gland cannot function properly without them. People who do not have access to natural sources of iodine in their diet, such as fish and other seafood, are at high risk of developing thyroid disorders. In North America, the problem has been virtually eliminated because iodine has been added to our table salt. However, other countries have not yet addressed this issue and iodine deficiency continues to be one of the world’s most pressing health problems.
Current tests for thyroid disorders are quite sensitive and precise, making it possible to get a very accurate diagnosis of hypothyroidism. If your doctor suspects that your symptoms are caused by an underactive thyroid gland, he or she will order blood tests to confirm the diagnosis. One test will measure the level of T4 in your blood; if you have hypothyroidism, the T4 levels will be low. When your condition is mild, however, it’s possible that your blood levels of both T4 and T3 could measure in the normal range. In that case, you may be tested for the level of TSH in your blood—a high TSH level will confirm the diagnosis of thyroid failure.
Sometimes, an additional test may be necessary to detect the presence of antithyroid antibodies in your blood. This will help your doctor determine if your hypothyroidism is caused by the immune condition Hashimoto’s thyroiditis. Elderly people may also undergo further laboratory testing to find out if the thyroid condition is putting extra stress on the heart or raising blood pressure or cholesterol levels.