Hypothyroidism, or low thyroid activity, means your thyroid gland is not making enough hormones. The thyroid gland is located in the front of your neck, just below your Adam’s apple. It makes hormones that control metabolism. Metabolism is the pace of your body’s processes and includes things like your heart rate and how quickly you burn calories. Women, especially those older than 50 years of age, are more likely to have hypothyroidism than men are. If left untreated, hypothyroidism can cause obesity, joint pain, infertility and heart disease.
The symptoms of hypothyroidism tend to develop slowly. They can be different from case to case. Initial symptoms include slight fatigue and sluggishness. As your metabolism slows, you may develop other symptoms:
Anyone can develop the condition, including infants and teenagers.
Babies born without a thyroid gland or with a thyroid that doesn’t work properly don’t have many symptoms at first. They may have yellowing of the skin and the whites of their eyes (jaundice), a puffy face, frequent choking and a large tongue that sticks out slightly. As the disease progresses, infants may have trouble feeding and may not grow and develop normally. They may also be constipated, have poor muscle tone or be very sleepy. If it is not treated, hypothyroidism in infants can lead to physical and mental retardation. In the United States, newborn infants are screened for hypothyroidism before leaving the hospital.
Children and teens who develop hypothyroidism have the same symptoms as adults, but they may also experience:
The most common cause of hypothyroidism is an autoimmune disease called Hashimoto’s thyroiditis. Normally, antibodies produced by the immune system help protect the body against viruses, bacteria and other foreign substances. An autoimmune disease is when your immune system produces antibodies that attack your body's tissues and/or organs. With Hashimoto’s thyroiditis, antibodies attack the thyroid and keep it from producing enough hormones.
Other common causes of hypothyroidism include:
Some less common causes of hypothyroidism include:
You have an increased risk of developing hypothyroidism if you:
If you have symptoms of an underactive thyroid, your doctor will do tests to measure the levels of thyroid hormone and thyroid-stimulating hormone in your blood.
Some doctors recommend screening older women for hypothyroidism during routine physical examinations. Some also recommend screening pregnant women and women who are thinking about becoming pregnant.
Treatment for hypothyroidism is a synthetic thyroid hormone taken daily in pill form. This medicine will regulate hormone levels and shift your metabolism back to normal. It will also lower your LDL cholesterol and may help reverse weight gain. It may take a few tries to get the right dose of synthetic thyroid hormone. If you are not taking enough, you may continue to experience symptoms of hypothyroidism. If you are taking too much, you may have symptoms similar to those of hyperthyroidism (overactive thyroid disease). Your doctor can tell if you are taking the right dose of thyroid hormone based on how you feel, by examination and by blood testing.
Some medicines, supplements and foods may affect your body’s ability to absorb the synthetic thyroid hormone. Tell your doctor if you eat large amounts of soy products, are on a high-fiber diet or take other medicines such as iron supplements, calcium supplements, cholestyramine or aluminum hydroxide (found in some antacids).
If it is not treated, hypothyroidism can lead to other health problems. These include:
Written by familydoctor.org editorial staff