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 50, 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 the proper dosage is established.
The signs and symptoms of hypothyroidism vary widely, depending on the severity of the hormone deficiency. But in general, any problems you do 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 sluggishness, 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 symptoms may include:
- Increased sensitivity to cold
- Pale, dry skin, puffy face
- Hoarse voice
- An elevated blood cholesterol level
- Unexplained weight gain
- Muscle aches, tenderness and stiffness
- Pain, stiffness or swelling in your joints
- Muscle weakness
- Heavier than normal menstrual periods
- Brittle fingernail and hair
When hypothyroidism isn’t treated, signs and symptoms can gradually become more severe. Constant stimulation of your thyroid 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.
help control your body temperature, influence your heart rate, and help regulate the production of protein. Your thyroid gland also produces calcitonin, a hormone that regulates the amount of calcium in your blood.
The rate at which T-4 and T-3 are released is controlled by your pituitary gland and your hypothalamusan area at the base of your brain that acts as a thermostat for your whole system. The hypothalamus signals your pituitary gland to make a hormone called thyroid-stimulating hormone (TSH). Your pituitary gland then releases TSH—the amount depends on how much T-4 and T-3 are in your blood. Finally, your thyroid gland regulates its production of hormones based on the amount of TSH it receives.
Although this process usually works well, the thyroid sometimes fails to produce enough hormones.
Although anyone can develop hypothyroidism, you’re at an increased risk if you:
- Are a woman older than age 50
- Have an autoimmune disease
- Have a close relative, such as a parent or grandparent,with an autoimmune disease
- Have been treated with radioactive iodine or anti-thyroid medications
- Received radiation to your neck or upper chest
- Have had thyroid surgery (partial thyroidectomy)
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.
When your thyroid doesn’t produce enough hormones, the balance of chemical reactions in your body can be upset. There can be a number of causes, including autoimmune disease, treatment for hyperthyroidism, radiation therapy, thyroid surgery and certain medications.
Your thyroid is a small, butterfly-shaped gland located at the base of the front of your neck, just below your Adam’s apple. Hormones produced by the thyroid gland have an enormous impact on your health, affecting all aspects of your metabolism.
Your thyroid gland produces two main hormones, thyroxine (T-4) and triiodothyronine (T-3). They maintain the rate at which your body uses fats and carbohydrates,
ism, 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.