Postpartum Thyroiditis : The Thyroid Gland

of Thyroxine to T3 in the tissues). After 2 months of treatment, her TSH levels increased by 371.15% and her Thyroxine levels

In order to evaluate thyroid function and diagnose thyroid diseases such as hyperthyroidism or hypothyroidism, the free thyroxine (free T4) lab test is performed usually after discovering that the thyroid stimulating hormone (TSH) level is abnormal (Porth C 2014 p.1288)

Most T3 and T4 released into the bloodstream are bound to proteins. Only the "free" component is biologically active and it is this component which decides the manifestations of thyrotoxicosis. The hormones exert their effects mainly by binding to nuclear receptors in cells to affect expression of genes.

Incidentally, there are actually two compounds made in the thyroid that are called thyroid hormone. The most abundant is T4, also known as thyroxine, which is then converted to T3, or triiodothyronine. T3 is the active form that produces the effects on metabolism.

Karen Holt describes in her 2010 article Graves’ Disease: Clinical Pathophysiology, Presentation and Treatment Options of certain genetic markers that cause the blood vessels surrounding the thyroid gland to dilate, most often occurring in the second to third decade of life. The dilation of these vessels causes an increase in blood flow and thyroid-stimulating antibodies excite thyrotropin receptors on the gland itself in the same manner that TSH usually works. These antibodies, known as TSAb, bypass the negative feedback loop that TSH works under causing the follicles to produce thyroid hormones in copious amounts without the ability to turn themselves “off”. This in turn causes the thyroid gland to hypertrophy and grow as much as 2 to 3 times its normal size (p. 13-14). In an effort to stop the overproduction of thyroid hormones the pituitary gland will stop making TSH and this becomes part of the diagnosing for Graves’ disease when assessing hyperthyroidism. Increased levels of free T3 and T4 along with an almost non-detectable level of TSH in a blood screen are very indicative of Graves’ disease (Holt, 2010, p. 14). There is no cure for Graves’ disease, but it is treatable with lifestyle adjustments as well as drug therapy it can be managed to a point (p 46).

Hypothyroidism is caused by the thyroid’s gland inability to produce thyroid hormone as required by the body. The diagnosis of hypothyroidism requires the laboratory testing of the thyroid stimulating hormone known as TSH. When the TSH is found to be elevated, a clinician should repeat the test along with a free thyroxine (T4) measurement. If the TSH is found to be elevated, while the T4 is normal, the patient is said to suffer from subclinical hypothyroidism. However, if the TSH is elevated and the T4 is low, the diagnosis is primary hypothyroidism (Gaitonde et al., 2012).

The thyroid is a small gland that rests in the lower neck. It is in charge of controlling the body’s metabolism by producing hormones (such as T3 and T4) that tell the body’s cells how much energy to use (2). The pituitary gland is in charge of monitoring the quantity of thyroid hormones in the bloodstream (2).

Thyrotoxicosis is a clinical condition caused by excess circulating serum thyroxine (T4), triiodothyronine (T3), or both with suppression of thyroid-stimulating hormone (TSH). A negative feedback loop involving the hypothalamus, pituitary, and thyroid gland regulates the production and release of thyroid hormones. (Fig. 1) The hypothalamus releases thyroid-releasing hormone (TRH), stimulating the pituitary gland to release TSH, in turn stimulating the thyroid gland to release T4 and T3. Enhanced production of T4 and T3

The thyroid gland is the gland that makes and stores hormones that help regulate the heart rate, blood pressure, body temperature, and metabolism. Thyroid hormones are essential for the function of every cell in the body. They help regulate growth and the rate of chemical reactions in the body. Thyroid hormones also help children grow and develop. The thyroid gland is located in the lower part of the neck, below the Adam's apple, wrapped around the trachea. It has the shape of a butterfly with two lobes attached to one another by a middle part called the isthmus. The thyroid uses iodine, a mineral found in some foods and in iodized salt, to make its hormones. The two most important thyroid hormones are thyroxine (T4) and triiodothyronine

This process originates in the hypothalamus when thyrotropin, otherwise known as TRH, is secreted and passes through the hypothalamic vein (Kapustin, 2010). Once the thyrotropin reaches the TRH receptors, they bind and make genes synthesize a thyroid stimulating hormone, otherwise known as TSH (Kapustin, 2010). When the pituitary makes mature TSH, thyroxin and triiodothyronine hormones are produced and secreted and implements a complicated negative feedback process that low levels of thyroxine and triiodothyronine cause TSH levels to rise and high levels of thyroxine and triiodothyronine cause levels of TSH to decrease (Huether & McCance, 2012). Not enough credit is given to this little thyroid gland on the front of the neck. The thyroid helps regulates powerful hormones that are required for growth and development as well as maintaining homeostasis. If we don’t have enough of the thyroid hormone, myxedema can occur. Myxedema can cause multiple organ complications that lead to serious illnesses. For example, with myxedema affecting the heart, complications such as pericardial effusion and bradycardia can occur and with myxedema affecting the reproductive organs, infertility can occur (Kapustin,

The thyroid gland is found in the front of the neck and produces two main hormones. The hormones are called thuroxine (T4) and Triiodothyronine (T3). Together these hormones regulate the body’s metabolism by increasing energy use in cells, regulate growth and development, help to maintain body temperature and aid in oxygen consumption. These two hormones are regulated by hormones produced by the hypothalamus and pituitary gland. The hypothalamus senses changes in body’s metabolic rate and releases a hormone known as thyropin-releasing hormone (TRH). This hormone then flows through connecting vessels to the pituitary gland which signals it to release another hormone. This hormone is known as thyroid-stimulating hormone (TSH). TSH then makes

Thyroxine (T4) is the key hormone produced in the thyroid gland. Low levels of T4 produce hypothyroidism, and high levels produce hyperthyroidism. Thyroxine converts to triiodothyronine (T3), which is a more biologically active hormone. Only about 20% of triiodothyronine is actually formed in the thyroid gland. The rest is manufactured from circulating thyroxine in tissues outside the thyroid, such as those in the liver and kidney. Once Thyroxine (T4) and Triiodothyronine are in circulation, they typically bind to substances called thyroid hormone transport proteins, after which they become inactive. The follicular cells of the thyroid gland perform all the necessary functions required to make and secrete the thyroid hormones.

These hormones have a critical role in cell differentiation during development and help maintain thermogenic and metabolic homeostasis in the adults.12 Thyroid disorders are highly prevalent in the population and mostly affect women in childbearing age.13 In pregnancy, thyroid gland displays mild to moderate enlargement because of increased physiological demands. Thyroid function is altered by 4 factors in pregnancy: i) the transient increase in human chorionic gonadotropin (hCG) during the first trimester, which cross-reacts with thyroid-stimulating hormone (TSH) receptor; ii) the estrogen-induced rise in thyroxine-binding globulin (TBG) which is the major transport protein for thyroid hormone; iii) increased autoimmunity; and iv) increased urinary iodide clearance, which can cause impaired thyroid hormone production in areas of low iodine supply.12,14-17 Consequently, the levels of both T3 and T4, the major hormones released by the thyroid, increase by ~50% and serum TSH levels decrease in the first trimester and increase in the second and third

The thyroid gland is located in the neck. This gland produces the hormones that help control the metabolism. With age, said gland can become protruding (nodular). The metabolism decreases with time, beginning around 20 years of age. Because thyroid hormones are produced and broken down (metabolized) at the same rate, tests of thyroid function are usually still normal. In some people thyroid hormone levels may rise, leading to an increased risk of dying from cardiovascular disease.

We agree that the answer to this question is A: increased TSH. In most patients, hypothyroidism is a result of abnormal development of the thyroid gland (Congenital Hypothyroidism, 2015). This abnormal development poses the largest threat when T4 levels are decreased. Decreased T4 values trigger the pituitary gland to respond by producing thyroid stimulating hormone (TSH). Because the thyroid gland is malformed, the low T4 levels cause the pituitary gland to continually receive signals from the hypothalamus that more TSH needs to be produced. In conclusion, when lab results display a low T4 level and an elevated TSH level, the suspicion of hypothyroidism is confirmed.