Thyroid & Parathyroid Disorders

What is the thyroid gland?

The thyroid is a 2-inch-long, butterfly-shaped gland weighing less than an ounce. Located in the front of the neck below the larynx, or voice box, it is composed of two lobes, one on each side of the windpipe. The thyroid is one of the glands that make up the endocrine system. The endocrine glands produce, store, and release hormones into the bloodstream that travel through the body and direct the activity of the body’s cells. Thyroid hormones regulate metabolism—the way the body uses energy—and affect nearly every organ in the body.

The thyroid gland makes two thyroid hormones, triiodothyronine (T3) and thyroxine (T4). Thyroid hormones affect metabolism, brain development, breathing, heart and nervous system functions, body temperature, muscle strength, skin dryness, menstrual cycles, weight, and cholesterol levels.

A third hormone produced by the thyroid gland, calcitonin, is not considered a thyroid hormone as such, but affects calcium levels in the blood and controls the buildup of calcium in the bones.

Thyroid hormone production is regulated by thyroid-stimulating hormone (TSH), which is made by another gland in the endocrine system called the pituitary, located in the brain.

Thyroid Disorders

What is Graves’ disease?

Graves’ disease, also known as toxic diffuse goiter, is the most common cause of hyperthyroidism in the United States. Hyperthyroidism is a disorder that occurs when the thyroid gland makes more thyroid hormone than the body needs.

The thyroid is a small, butterfly-shaped gland in the front of the neck below the larynx, or voice box. The thyroid gland makes two thyroid hormones, triiodothyronine (T3) and thyroxine (T4). Thyroid hormones affect metabolism, brain development, breathing, heart and nervous system functions, body temperature, muscle strength, skin dryness, menstrual cycles, weight, and cholesterol levels.

Thyroid hormone production is regulated by another hormone called thyroid-stimulating hormone (TSH), which is made by the pituitary gland located in the brain.

Graves’ disease is an autoimmune disorder, meaning the body’s immune system acts against its own healthy cells and tissues. In Graves’ disease, the immune system makes antibodies called thyroid-stimulating immunoglobulin (TSI) that attach to thyroid cells. TSI mimics the action of TSH and stimulates the thyroid to make too much thyroid hormone. Sometimes the antibodies can instead block thyroid hormone production, leading to a confusing clinical picture. The diagnosis and treatment of Graves’ disease is often performed by an endocrinologist—a doctor who specializes in the body’s hormone-secreting glands.

What is Hashimoto’s disease?

Hashimoto’s disease, also called chronic lymphocytic thyroiditis or autoimmune thyroiditis, is a form of chronic inflammation of the thyroid gland. The inflammation results in damage to the thyroid gland and reduced thyroid function or “hypothyroidism,” meaning the gland doesn’t make enough thyroid hormone for the needs of the body. Hashimoto’s disease is the most common cause of hypothyroidism in the United States.

The thyroid is a small, butterfly-shaped gland in the front of the neck below the larynx, or voice box. The thyroid gland makes two thyroid hormones, triiodothyronine (T3) and thyroxine (T4). Thyroid hormones circulate throughout the body in the bloodstream and act on virtually every tissue and cell in the body. These hormones affect metabolism, brain development, breathing, heart rate, nervous system functions, body temperature, muscle strength, skin moisture levels, menstrual cycles, weight, cholesterol levels, and more.

Thyroid hormone production is regulated by another hormone called thyroid-stimulating hormone (TSH). TSH is made by the pituitary gland, a pea-sized gland located in the brain. When thyroid hormone levels in the blood are low, the pituitary releases more TSH. When thyroid hormone levels are high, the pituitary responds by dropping TSH production.

Hashimoto’s disease is an autoimmune disorder, meaning the body’s immune system attacks its own healthy cells and tissues. In Hashimoto’s disease, the immune system makes antibodies that attack cells in the thyroid and interfere with their ability to produce thyroid hormone. Large numbers of white blood cells called lymphocytes accumulate in the thyroid. Lymphocytes make the antibodies that drive the autoimmune process.

What is hyperthyroidism?

Hyperthyroidism is a disorder that occurs when the thyroid gland makes more thyroid hormone than the body needs. It is sometimes called thyrotoxicosis, the technical term for too much thyroid hormone in the blood. About 1 percent of the U.S. population has hyperthyroidism.1 Women are much more likely to develop hyperthyroidism than men.

What is hypothyroidism?

Hypothyroidism occurs when the thyroid gland does not produce enough thyroid hormone to meet the body’s needs. Without enough thyroid hormone, many of the body’s functions slow down. About 5 percent of the U.S. population has hypothyroidism. 1 Women are much more likely than men to develop hypothyroidism.

Parathyroid Disorders

Most people have four pea-sized glands, called parathyroid glands, on the thyroid gland in the neck. Though their names are similar, the thyroid and parathyroid glands are completely different. The parathyroid glands make parathyroid hormone (PTH), which helps your body keep the right balance of calcium and phosphorous.

If your parathyroid glands make too much or too little hormone, it disrupts this balance. If they secrete extra PTH, you have hyperparathyroidism, and your blood calcium rises. In many cases, a benign tumor on a parathyroid gland makes it overactive. Or, the extra hormones can come from enlarged parathyroid glands. Very rarely, the cause is cancer.

If you do not have enough PTH, you have hypoparathyroidism. Your blood will have too little calcium and too much phosphorous. Causes include injury to the glands, endocrine disorders or genetic conditions. Treatment is aimed at restoring the balance of calcium and phosphorous.