Hypothyroidism is a condition where the thyroid gland is under active and does not make suffice amount of thyroid hormones in the bloodstream. Hashimoto’s disease is the most common form of hypothyroidism; it is an autoimmune condition where the immune system attacks the thyroid. In the United States about 20 million people are diagnosed with thyroid issues, 60% are undiagnosed and unaware they have it.
The human body relies on thyroid hormones to ensure the proper functioning of cells, such as regeneration, proteins production, glucose storage, creation of new enzymes, and synthesizing DNA (Haran, 2005). If the thyroid produces in excess or in deficit, these essential processes will not continue to work properly; most tissues in the body are affected and influenced by the thyroid gland and thyroid hormones. The thyroid runs our metabolism, heart rate, blood pressure, body temperature, mood, menstrual cycle, etc. It pretty much it controls every cell in our body. It’s important gland for our overall health.
The thyroid gland is a very small and butterfly-shape located in front of the neck below the Adam’s apple or laryngeal prominence, the gland wraps partly around the trachea or windpipe. It is composed of units called follicles, and in the center of these follicles is colloid filled with storage protein called thyroglobulin, which is a huge glycoprotein. The follicles secrete colloid and the thyroid hormones are made within the follicles (Germann & Stanfield, 2005). There are many glands that regulate the activity of thyroid hormones. It starts with the hypothalamus and the pituitary gland. The hypothalamus and pituitary gland are connected to each other at the base of the brain. In the brain, the hypothalamus secretes its hormone thyrotropin-releasing hormone (TRH),then the pituitary gland produces a hormone called thyroid stimulating hormone (TSH), which is usually the first lab and sometimes the only lab that gets tested. The TSH is released into the bloodstream to activate the thyroid cells, which then secretes T3 and T4 into the peripheral tissues (Hershman, 2002). TSH is made when TSH and TRH are to ensure that hormone availability remains constant in the internal body environment, maintaining the body’s homeostatic levels of T3 and T4. When the pituitary produces enough TSH this causes negative feedback, signaling the cells of hypothalamus to turn off TRH. Without TRH, or no or little TSH is produced. The pituitary gland also shuts down when there are signs that there is too much T3 or T4 hormone production and negative feedback. Conversely, when there is not enough T3 or T4 being produced and circulating throughout the body then hypothalamus increases TRH, which increases TSH. The thyroid depends on two hormones that are secreted from the thyroid gland: the main hormone is thyroxine (T4) and triiodothyronine (T3). A large amount about 60% of T4 gets converted into T3 once these hormones get released from the thyroid gland into the blood. T3 is the most biological activity, being more active than T4 in affecting the metabolism of cells; it represents 99.9% of thyroid hormones activity (Mathur, 2006).
There are glands that regulate the activity of thyroid hormones, such as the pituitary gland and the hypothalamus. The hypothalamus and pituitary gland are connected to each other at the base of the brain. In the brain, the pituitary gland produces a hormone called thyroid stimulating hormone (TSH), which tells the thyroid gland to produce the right amount of hormones. The TSH is released into the bloodstream to activate the thyroid cells, which then secretes T3 and T4 into the peripheral tissues (Hershman, 2002). TSH is made when the hypothalamus secretes its hormone thyrotropin-releasing hormone (TRH). TSH and TRH are to ensure that hormone availability remains constant in the internal body environment, maintaining the body’s homeostatic levels of T3 and T4. When the pituitary produces enough TSH this causes negative feedback, signaling the cells of hypothalamus to turn off TRH. Without TRH, or no or little TSH is produced. The pituitary gland also shuts down when there are signs that there is too much T3 or T4 hormone production and negative feedback. Conversely, when there is not enough T3 or T4 being produced and circulating throughout the body then hypothalamus increases TRH, which increases TSH.
Iodine is essential for the thyroid gland; it is required for the cells to produce T3 and T4 since each of these hormones contain T3 and T4 iodine, the thyroid gland removes iodine from the blood, which then enables the production of the two hormones. The iodine goes into the thyroid cells and it will combine with amino acids called tyrosine to form a large thyroglobulin molecule, which is found in the center of the follicles. Iodine mostly comes from our diet, such as seafood, bread, salt, or other iodine-rich food.. If the thyroid gland does not have a sufficient amount of iodine it is unable to produce an adequate amount of the thyroid hormones, which can have serious health consequences. Iodine deficiency is mostly found in inland areas where people do not have access to iodine-rich soils both of which are readily available in coastal areas. Iodine deficiency initially results in hyperthyroidism, which can lead to things such as anxiety, heart palpitations, insomnia, hair loss, and weight loss (Brown, 2003).
Thyroid hormones have a major role in brain development. Thyroid hormone are also very crucial for normal body growth. The importance of thyroid hormones for healthy growth begins even before birth, being critical to the fetal development. During pregnancy, the fetal thyroid begins to grow around the first trimester. However, it is the second trimester where the developing fetus start making its own T4 and T3, but still relies on the maternal hormones throughout pregnancy. During this vital brain development stage, thyroid hormones play an important role. Crucial brain development begins before the fetus’s thyroid system is properly working, so maternal thyroid has to be available until birth before when the baby’s thyroid should begin to function appropriately (Brown, 2003). According to Valerie Brown, a writer for the Environmental Health Perspectives, an exogenous chemical such as an uptake in iodine may disrupt that delicate balance and have environmental effects on thyroid gland hormones and the effects in normal body growth. Brown also states that in fetal and childhood development environmental factors may have their greatest impact. If the thyroid role has a complication during development, neurodevelopmental problems may result, such as mental retardation. This could be prevented or likelihood reduced by administering postnatal thyroid hormones (Brown, 2003). There are other neurodevelopmental problems, such as synapse development (the communication between two neurons to transmit a message), formation of myelin (a tissue that conducts a message faster), and migration of neurons that lead to the accurate locations in the brain. These factors demonstrate how critical thyroid hormones are to the brain development (Brown, 2003).
Hypothyroidism is highly more common in women than in men. This could be due to the fact that some thyroid diseases are autoimmune diseases, and more women have autoimmone conditions than men (Katz, 2006). People affected most by hyperthyroidism are women in their twenties and thirties, and it especially common immediately after pregnancy. (Katz, 2006). According to the Thyroid Foundation of America, “about 13 million Americans have thyroid disorders, and which 11 million are women, and more than half are undiagnosed” (Brown, 2003). Besides the most common hyperthyroidism, condition known as Graves’ disease, there is also Hashimoto’s disease is an autoimmune thyroiditis. Thyroiditis is an inflammation of the thyroid gland. It is associated to a temporary hyperthyroidism that is followed by hypothyroidism, (an underactive thyroid) which does not produce enough thyroid hormones. Hashimoto’s disease is most common in women, and after initial inflammation, it causes an enlarged thyroid gland or goiter as the remaining tissue ties to make more T3 and T4. Dr. Jerome Hershman and other researchers have found an antibody measurement called thyroid peroxidase antibody some women; this can show up after pregnancy. Approximately, 20% of Hashimoto’s patients have this antibody in their blood (Hershman, 2002).
There are many signs and symptoms to hyperthyroidism, such as rapid heartbeat, tremor of the hands, inability to concentrate, anxiety, increased appetite, increased perspiration, insomnia, prominent eyes that protrude from the socket (exophthalmos), edema (lower leg swelling), enlarged thyroid gland, and feeling fatigue throughout the day. It can lead to menstrual irregularities that could decrease a woman’s chances of being able to get pregnant. Too much thyroid can also cause muscles weakness, which in turn can affect the bones and increase the chances of developing osteoporosis. Since some of the signs and symptoms for hyperthyroidism are are somewhat obscure and can be overlooked, a blood test is needed before you are able to diagnose this disease. The TSH blood test is the best way to check if there are abnormal levels of the thyroid hormones of T3 and T4. If there is too much thyroid hormone then the TSH will be low due to negative feedback.
Hyperthyroidism may be treated of radioactive iodine or antithyroid drugs, such such as Propylthiouracil (PTU) and Methimazole (tapazole) (Katz, 2006). The use of radioactive iodine in a pill or liquid form will shrink the thyroid gland cells; the cellular damage of the thyroid causes slowing down of thyroid hormones production. enabling the thyroid gland to function properly and produce normal levels of thyroid hormone. The antithyroid drugs can be taken orally and will block the effect of thyroid hormones and they will also help lower the level of thyroid hormones in the blood and bring them back to normal. Surgery is usually not necessary to treat hypothyroidism. However, if a person has a condition such as an overactive nodule(lump on the thyroid), which may act as benign tumor, the patient would undergo surgery and have most of the thyroid gland removed.
Given how crucial the thyroid gland and thyroid hormones are to healthy functioning body, hypothyrodism should be treated immediately. If it is undiagnosed for too long, it can cause serious damage to organ systems of the body, such as bones, muscle, metabolism, and growth.