The thyroid is a small, butterfly-shaped gland at the base of the neck, above the collarbones. The thyroid makes hormones that regulate your body’s metabolism—the way your body uses energy. If your thyroid doesn't work properly, critical body functions, such as heart rate and energy, can be affected. Javaid Wani, MD, an endocrinologist in Myrtle Beach, South Carolina, shares insights on what you need to know about thyroid disorders.
Thyroid hormones
The thyroid produces two main hormones—T4 (thyroxine) and T3 (triiodothyronine). These hormones travel through your bloodstream and impact the function of almost every cell, tissue, and organ in your body. Thyroid-stimulating hormone (TSH), which is made in the pituitary gland, controls the release of thyroid hormones.
When everything is working normally, the pituitary gland releases more TSH when thyroid hormone levels are low and less TSH when thyroid hormone levels are high. But sometimes things can go wrong, causing the release of too little or too much thyroid hormones.
According to the American Thyroid Association, an estimated 20 million Americans have some form of thyroid disease. If left untreated, thyroid disorders can cause serious problems including cardiovascular disease, osteoporosis, and infertility.
Types of thyroid disorders
Thyroid disorders are typically understood as either being hypothyroidism or hyperthyroidism.
Hypothyroidism
“Hypothyroidism is a condition in which your thyroid gland doesn’t produce any or enough thyroid hormones needed by your body to function normally,” says Dr. Wani. Your metabolism slows as a result.
It is the most common type of thyroid disorder. Symptoms of hypothyroidism develop slowly over time and can be subtle. They may include:
- Feeling extremely tired, sluggish, and weak
- Weight gain
- Depression
- Constipation
- Difficulty concentrating or feeling “out of it”
- Pale, dry skin and thinning hair
- Frequent, heavier periods
Hyperthyroidism
Hyperthyroidism, or an overactive thyroid, occurs when your thyroid gland makes too much thyroid hormone. High levels of thyroid hormones speed up every function in the body. Symptoms of hyperthyroidism may include:
- Feeling nervous, irritable, and anxious
- Weight loss
- Trouble concentrating
- Excessive sweating and sensitivity to heat
- Difficulty sleeping
- Muscle weakness
- Diarrhea
- Vision problems and eye irritation
- Missed or light periods
- Heart racing or pounding
“In severe cases, particularly in advanced age, it usually causes irregular heartbeat causing various rhythm disorders, like atrial fibrillation,” says Wani. “If left untreated, it can cause severe damage to the heart muscle to the point that the heart doesn’t pump out blood.” This can result in congestive heart failure and may not be reversible, Wani says. In addition, hyperthyroidism can cause severe bone loss if left untreated.
Causes of thyroid disorders
Thyroid disorders are often caused by autoimmune disorders—conditions in which the immune system mistakenly attacks its own cells. For example, Graves’ disease can cause hyperthyroidism and Hashimoto’s disease can cause thyroiditis. Other causes of thyroid disorders include:
- A malfunctioning pituitary gland
- Iodine deficiency: The body uses iodine from food to make T3 and T4. Iodine deficiency is a major cause of goiter (an enlarged thyroid) in underdeveloped countries, but rare in the United States.
- Bacteria or viruses that cause inflammation of the thyroid (thyroiditis)
- Nutritional supplements that claim to benefit the thyroid: Many such supplements contain dangerously high levels of iodine that can lead to hyperthyroidism.
- Obesity: Being significantly overweight may indirectly cause hypothyroidism.
Who’s at risk of thyroid issues?
While anyone can develop a thyroid disorder, people assigned female at birth (AFAB) are more likely to be affected. In fact, one in eight people AFAB will develop thyroid problems during their lifetime. In many cases, thyroid disorders develop during or soon after pregnancy or menopause.
People over the age of 60 and those with a family history of a thyroid problem are also more likely to develop a thyroid disorder.
Diagnosing thyroid issues
Thyroid disorders can be diagnosed with blood tests that measure TSH and thyroid hormone levels and by detecting certain autoantibodies present in autoimmune-related thyroid disease.
If your healthcare provider (HCP) is concerned about your thyroid, they will do a TSH test. The TSH test is the most accurate test for diagnosing both hyper- and hypothyroidism. If the results are atypical, other tests will be performed, including free T4, TPO (thyroid peroxidase antibody), and TgAb (thyroglobulin antibody), says Wani. If hyperthyroidism is suspected, TSI (thyroid stimulating immunoglobulin) will be checked.
Imaging tests like ultrasound or nuclear medicine tests are used to determine if there is an anatomical or structural abnormality affecting the thyroid, such as a nodule, says Wani. Nuclear medicine tests use small amounts of radioactive material to create a picture of the thyroid and provide information about its structure and function. If thyroid cancer is suspected, your HCP will perform a biopsy.
Treatment for thyroid issues
If you find a lump or growth on your thyroid or notice any unusual symptoms, see your HCP. Hypothyroidism can be treated with synthetic thyroid hormones (usually levothyroxine).
Hyperthyroidism can be more difficult to treat. Treatment may include antithyroid medicine to block thyroid hormone production, beta-blockers to reduce elevated heart rate in certain patients, radioactive iodine treatment to destroy the thyroid, or thyroid surgery to remove part or all of the thyroid gland. The most common treatment is radioactive iodine. This treatment often causes hypothyroidism, requiring life-long treatment with synthetic thyroid hormone.
Unless it’s cancer or causing bothersome symptoms, most nodules or thyroid goiters can be watched with follow-up ultrasounds every 9 to 24 months, says Wani. Surgery is done if the biopsy shows cancer or if the nodule continues to grow and causes dangerous symptoms like breathing or swallowing problems, he says. Following surgery for thyroid cancer, oral radioactive iodine treatment may be given to kill any residual thyroid tissue.
Although thyroid disorders usually require a lifetime of treatment with hormones to maintain normal thyroid function, most people go on to live healthy, productive lives.
