The thyroid is an important gland located in the front part of the neck, which produces hormones that regulate metabolism throughout your body. Thyroid hormone (TH) plays a number of important roles in the body, including regulating the breakdown of fats, proteins, and carbohydrates, regulating heat production, maintaining healthy bones and muscle tone, promoting growth, and maintaining normal lung and heart function. Illnesses that disrupt the amount of TH being released by the thyroid gland can be classified into two categories: hyperthyroidism, which is the production of too much TH, and hypothyroidism, which is the production of too little TH. Both are serious conditions that require medical treatment and routine monitoring.
Thyroid Hormone
The amount of TH that the thyroid gland produces is dependent on other areas of the body, including the hypothalamus (which is in the brain) and the pituitary gland. When TH is low, the hypothalamus releases a chemical that tells the pituitary to then release Thyroid Stimulating Hormone (TSH). TSH lets the thyroid gland know it is time to release more TH. When the TH level rises, the pituitary slows down the release of TSH. This process is known as negative feedback.
There are a number of other things that influence the amount of TH released. Increased metabolic demands, as a result of things like illness or physical activity, can cause an increase in TH, as will exposure to extreme cold. Your nutritional state can also affect the production of TH. Iodine is a necessary component of the hormone, so iodine deficiency will decrease production. Other things that may influence TH levels include one’s sex, pregnancy, and stress.
Once released, TH exerts a great deal of influence on a number of bodily functions. It regulates the breakdown of nutrients and the metabolic rate of your cells. It also regulates body heat production, heart rate and efficiency, rate of respiration, and plays a role in regulating your blood sugar and red blood cell production. Sufficient levels are necessary for adequate muscle tone, and for normal brain development during pregnancy.
Hyperthyroidism
When the thyroid produces and releases too much TH, it is called hyperthyroidism. This illness affects women more than men, most frequently between 20 and 40 years old. The most common cause of spontaneous hyperthyroidism is Graves’ disease—an autoimmune disease in which a person’s immune system attacks the thyroid gland and causes it to make too much TH. Other causes of hyperthyroidism include goiter (overgrowth of the thyroid gland), tumors, inflammation of the thyroid, overuse of thyroid hormone, and some medications.
The symptoms of hyperthyroidism are caused by the effects of high amounts of TH on the body’s tissues, and can sometimes be mistaken for psychiatric illnesses. The most common symptoms include nervousness, anxiety, increased sweating, fatigue, erratic mood changes, tremors, increased appetite, diarrhea, weight loss, skin and hair changes, double vision, bulging eyes, menstrual changes, a rapid heart rate, and heat intolerance. If you are experiencing any of these symptoms, you should seek medical attention. Typical lab values will include a low TSH and high free T4. Your doctor may run other tests to determine why you are secreting high levels of TH.
Treatment may include medications to relieve symptoms, such as beta-blockers or other medications to suppress the secretion of TH. Additional treatments include the ingestion of radioactive iodine, which destroys thyroid cells, and surgical removal of the thyroid gland. If left untreated, hyperthyroidism can result in heart disease, osteoporosis, mental illness, infertility and even death.
Hypothyroidism
When the thyroid is producing less than adequate amounts of TH, it is known as hypothyroidism. This is a common, treatable, and usually slowly progressive illness. In fact, symptoms often go unnoticed until routine screening tests have been done. Because TH is so important in growth and development, there are serious consequences for newborns and children who go undiagnosed and untreated. This is why all newborns are tested.
In adults, women—especially older women—are more likely to experience hypothyroidism than men. The most common cause in the U.S. is the autoimmune illness called Hashimoto’s thyroiditis, which often runs in families. Other causes include iodine deficiency, treatment for hyperthyroidism, surgical removal of the thyroid gland, or failure of the pituitary or hypothalamus to stimulate the thyroid to produce TH.
Because TH is essential for all the metabolic processes in the body, growth and development, and tissue health, low levels result in a variety of symptoms. People with hypothyroidism often experience extreme weakness and muscle fatigue, aches and pains, cramps, cold intolerance, constipation, weight gain, dry skin, hair loss, brittle nails, puffy eyes, swelling of the hands and face, and a slow heart rate. If you are experiencing any of these symptoms, you should consult your primary care physician for evaluation.
In contrast to the lab results found in hyperthyroidism, people with hypothyroidism have a high TSH and low free T4. They may also have low sodium levels and a low blood sugar.
The treatment for hypothyroidism is hormone replacement, and the usual medication used is levothyroxine, which is a synthetic preparation of the hormone. A number of factors, including severe illness, major surgery, pregnancy, and certain medications can affect TH levels. If hypothyroidism is not controlled, the result can be breathing problems, mental illness, heart problems, inability to control the body’s temperature, and even coma. This is why ongoing monitoring is necessary, so that dosages can be adjusted to ensure your levels are within a normal range.
Normal TH levels are essential to support your body’s metabolic needs. Both hyperthyroidism and hypothyroidism are treatable illnesses that require medical attention. If you are experiencing any of the aforementioned symptoms, or if you have any more questions regarding thyroid function, call Rockville Concierge Doctors at (301) 545-1811 to request an appointment, or request an appointment online.
