The thyroid is a butterfly-shaped gland that sits low on the front of the neck. Your thyroid lies below your Adam’s apple, along the front of the windpipe. The thyroid has two side lobes, connected by a bridge (isthmus) in the middle. When the thyroid is its normal size, you can’t feel it. The thyroid secretes several hormones, collectively called thyroid hormones. The main hormone is thyroxine, also called T4. Thyroid hormones act throughout the body, influencing metabolism, growth and development, and body temperature. During infancy and childhood, adequate thyroid hormone is crucial for brain development.
The statistics on thyroid problems in the U.S. are daunting. Consider that:
- More than 12 percent of the U.S. population will develop a thyroid condition during their lifetime.
- An estimated 20 million Americans have some form of thyroid disease.
- Up to 60 percent of those with thyroid disease are unaware of their condition.
- Women are five to eight times more likely than men to have thyroid problems.
- One woman in eight will develop a thyroid disorder during her lifetime.
Undiagnosed thyroid disease may put patients at risk for certain serious conditions, such as cardiovascular diseases, osteoporosis and infertility. Pregnant women with undiagnosed or inadequately treated hypothyroidism have an increased risk of miscarriage, preterm delivery, and severe developmental problems in their children. Though most thyroid diseases are life-long conditions, these can be managed with medical attention.
The symptoms of hyperthyroidism, in which the body produces too many thyroid hormones, may include:
- Weight loss, despite increased appetite
- Increased heart rate, heart palpitations, higher blood pressure, nervousness, and excessive perspiration
- More frequent bowel movements, sometimes with diarrhea
- Muscle weakness, trembling hands
- Development of a goiter (an enlargement in your neck)
- Lighter or shorter menstrual periods
The symptoms of hypothyroidism, in which the body doesn’t produce enough thyroid hormones, may include:
- Lethargy, slower mental processes or depression
- Reduced heart rate
- Increased sensitivity to cold
- Tingling or numbness in the hands
- Development of a goiter (an enlargement in your neck)
- Constipation, heavy menstrual periods, or dry skin and hair
There are number of methods physicians use to test for thyroid imbalance. These include:
- Anti-TPO antibodies: In autoimmune thyroid disease, proteins mistakenly attack the thyroid peroxidase enzyme, which is used by the thyroid to make thyroid hormones.
- Thyroid ultrasound: A probe is placed on the skin of the neck, and reflected sound waves can detect abnormal areas of thyroid tissue.
- Thyroid scan: A small amount of radioactive iodine is given by mouth to get images of the thyroid gland. Radioactive iodine is concentrated within the thyroid gland.
- Thyroid biopsy: A small amount of thyroid tissue is removed, usually to look for thyroid cancer. Thyroid biopsy is typically done with a needle.
- Thyroid stimulating hormone (TSH): Secreted by the brain, TSH regulates thyroid hormone release. A blood test with high TSH indicates low levels of thyroid hormone (hypothyroidism), and low TSH suggests hyperthyroidism.
- T3 and T4 (thyroxine): The primary forms of thyroid hormone, checked with a blood test.
- Thyroglobulins: A substance secreted by the thyroid that can be used as a marker of thyroid cancer. It is often measured during follow-up in patients with thyroid cancer. High levels indicate recurrence of the cancer.
- Other imaging tests: If thyroid cancer has spread (metastasized), tests such as CT scans, MRI scans, or PET scans can help identify the extent of spread.
If you are experiencing symptoms of thyroid imbalance, it is important to contact your physician and arrange for an exam and thyroid hormone test.