Ana Maria Kausel, MD, is a double board-certified endocrinologist affiliated with Mount Sinai St. Luke's/Mount Sinai West in New York City.
Hypothyroidism occurs when your thyroid gland does not produce enough thyroid hormone. Since thyroid hormones regulate your body's metabolism and temperature, when a deficiency occurs, your body has trouble using energy and staying warm. Common symptoms include fatigue, feeling cold, constipation, and slight weight gain.
The main blood test used to diagnose hypothyroidism is the thyroid-stimulating hormone (TSH) test. TSH, which is produced and released by the pituitary gland, rises when it detects low levels of thyroid hormone.
The treatment of hypothyroidism involves taking a daily medication that replaces the missing thyroid hormone in the body. Levothyroxine is the most commonly prescribed thyroid hormone replacement drug.
While there are many causes of hypothyroidism, the main cause in the U.S. is an autoimmune disease called Hashimoto's thyroiditis. With this disease, a person’s own immune system misguidedly attacks their thyroid gland. Other causes of hypothyroidism include the use of certain medications, surgical removal of the thyroid gland, and radiation therapy, to name a few.
Not necessarily. Hypothyroidism describes a thyroid gland that produces too little or no thyroid hormone. While the primary cause of hypothyroidism in the United States is an autoimmune disease called Hashimoto's thyroiditis, there are other causes of hypothyroidism that are not autoimmune related.
Losing weight with hypothyroidism can be tricky. Research suggests that even if your TSH level is within the "normal" range, slight variations may contribute to weight gain. After partnering with a doctor who understands your situation, some key approaches to bolstering your metabolism include adjusting your eating and sleeping patterns and improving your digestion with high-fiber foods.
The treatment of hypothyroidism involves taking a drug to bring your thyroid-stimulating hormone (TSH) level back to normal. Doctors usually prescribe levothyroxine, which is the synthetic form of the thyroid hormone T4 (thyroxine). Levothyroxine is an oral drug taken once daily that is available in both generic and brand-name formulations.
Hypothyroidism has many causes and is not by itself a genetic disease. That said, mutations in genes involved in the immune system likely play a role in the development of Hashimoto’s thyroiditis. This autoimmune disease is the leading cause of hypothyroidism in the United States.
The term "goiter" describes an abnormal growth of the thyroid gland. A goiter can occur for many reasons, including when thyroid hormone production is decreased (hypothyroidism), increased (hyperthyroidism), or normal (euthyroidism). Some people have no symptoms with a goiter. Others may experience discomfort, swelling, coughing, and/or difficulties swallowing.
Hashimoto's disease is an autoimmune disease in which a person's immune system attacks their own thyroid gland, impairing its ability to make thyroid hormone. This results in the slow onset of symptoms of hypothyroidism, such as mild weight gain and fatigue. Treatment is often lifelong with the thyroid hormone replacement drug, levothyroxine.
There are different types of thyroid diseases. Most commonly, thyroid disease results from an autoimmune or inflammatory process in which the gland underproduces or overproduces thyroid hormone. Thyroid surgery, trauma, and nodular growth may also result in thyroid disease. Cancer can also occur in the thyroid; although, it does not usually cause changes in thyroid hormone levels.
Thyroiditis means “inflammation of the thyroid gland.” The term encompasses several conditions that cause thyroid inflammation, such as Hashimoto’s thyroiditis, subacute thyroiditis, postpartum thyroiditis, silent (painless) thyroiditis, and drug-induced thyroiditis.
A TSH test measures the amount of thyroid-stimulating hormone in a patient’s bloodstream. TSH is produced and released by a person’s pituitary gland, which is located at the base of the brain. When the thyroid gland starts to malfunction and hormone levels drop too low, TSH levels rise in an effort to stimulate the thyroid gland into making more hormones.
T4 (thyroxine) is the main hormone released by the thyroid gland. There are two types of T4 tests, a total T4 test and a free T4 test. A free T4 test is used more commonly to diagnose hypothyroidism. A low free T4, along with a high TSH, is indicative of hypothyroidism.
American Thyroid Association. Hypothyroidism (underactive).
Jonklaas J, Bianco AC, Bauer AJ, et al. Guidelines for the treatment of hypothyroidism: prepared by the american thyroid association task force on thyroid hormone replacement. Thyroid. 2014;24(12):1670–1751. doi:10.1089/thy.2014.0028
Sanyal D, Raychaudhuri M. Hypothyroidism and obesity: An intriguing link. Indian J Endocrinol Metab. 2016;20(4):554–557. doi:10.4103/2230-8210.183454
Panicker V. Genetics of thyroid function and disease. Clin Biochem Rev. 2011;32(4):165-75.