Disorders and Diseases of the Thyroid - Research Paper Example

Disorders and Diseases of the Thyroid The thyroid is a gland inside of the human throat which is located on the trachea just below the larynx. It is responsible for maintaining the rate of chemical reactions in the cells of the body, otherwise known as the body's metabolism, through the secretion of various hormones. Proper function of the thyroid gland is then vital for the body to function within normal parameters, and especially for the body to grow and develop during the formative years of childhood and early adulthood. Unfortunately, however, disorders and diseases of the thyroid are not uncommon; these illnesses can have varying levels and types of detrimental effects on thyroid function (Mulryan, 2010). Introduction In evidence-based practice, only after the problem is understood and researched can medical professionals state a current best method of treatment. In this type of medical practice, medical professionals rely on cutting-edge research results to make treatment decisions, rather than on the older method of assuming that tradition and authority always held the right answers for a patient. The best patient care is recognized to be a combination of the current valid medical research, a practitioner's own experience and education, and the situation of an individual patient (Fineout-Overholt, Stillwell, Williamson, Cox, & Robbins, 2010). Applied to the area of thyroid dysfunction, evidence-based and best practice guidelines could mean recognizing the effect of a specific patient's lifestyle on their body's health in order to tell the difference between simple obesity and a depressed thyroid, for example, and keeping up with the most current literature on which types of thyroid hormones are considered to be most effective (Maas, 2007). Since by some estimates, as much as five percent of the general female population and more than twenty-five percent of the entire population over the age of seventy-five suffers from some form of thyroid disease, it is vitally important that the medical community understand these issues as they relate to thyroid dysfunction (Maas, 2007; Mulryan, 2010). Some types of thyroid dysfunction result in the over-production of metabolic hormones. This over-production results in a condition known as hyperthyroidism (Mulryan, 2010). Hyperthyroidism is most commonly seen in women until the age of sixty-five or seventy-five, at which point, as in seen in thyroid disease across the board, the incidence greatly increases and becomes equally likely between the sexes (Gutierrez, 2008). As would be expected from a gland whose purpose is to regulate the body's metabolism, hyperthyroidism leads to a severely increased basal metabolic rate. The overactive thyroid can produce as much as five to fifteen times the normal amount of thyroid hormones and can result in a myriad of detrimental effects on the rest of the body. This increase in secretion is achieved through an increase in the size and available cellular matrix of the thyroid gland, so that many more cells can live within the gland, as well as through an increase in the secretion of hormone by the individual thyroid cells (Hall, 2011). Generally, this condition is induced by a direct infection within or damage to the thyroid gland itself, though it can also occur rarely as a secondary disorder when there is a dysfunction in the pituitary or hypothalamus glands (McCance, Huether, Brashers, & Rore, 2010). The most common diseases that lead to either the primary or secondary dysfunction of the glands are auto-immune diseases, while some causes of reversible primary damage to the thyroid itself are an iodine deficiency in the diet or viral infection of the thyroid (Mulryan, 2010). Long-term hyperthyroidism is connected with an increase in patient morbidity and mortality, especially that related to cardiac disease and stroke (Biondi & Kahaly, 2010). Signs and Symptoms Despite the varying causes of hyperthyroidism, there exist a fairly distinct set of signs and symptoms that result from the condition regardless of the underlying disease (Mulryan, 2010). Unsurprisingly, these generally are the direct opposite of the fatigue and weight gain seen in patients with an under-active thyroid (Maas, 2007). Instead, hyperthyroidism generally results in anxiety, increased heart rate, and weight loss (Mulryan, 2010). A medical practitioner will generally be able to detect the tachycardia, as well as an irregular pulse rate. The enlargement of the hyperactive gland almost always results in a visible swelling in the patient's neck, as well as an audible blood noise over the location of the thyroid. Also nearly universal is unintentional weight loss and changes in appetite usually resulting in an increased caloric intake but sometimes involving a loss of interest in food (McCance et al., 2010). The increased metabolic rate results in extremely low heat tolerance, as well as increased sweating, hand tremors, and difficulty sleeping (Mulryan, 2010). Unexpectedly, sub-clinical or mild hyperthyroidism is can also manifest with symptoms of fatigue and apathy (American Academy of Family Physicians, 2011). This is likely due to the loss of muscle tissue in the patient, since the weight loss is non-specific and includes both lean and fat body mass (Brent, 2008). The significant majority of hyperthyroid cases are due to Grave's disease, an auto-immune condition that is five to ten times more likely in women than in men (Brent, 2008). While the cause of Graves' disease is not empirically known, research suggests that it results from a combination of genetic factors and environmental triggers (Hegedüs, 2009). Patients who suffer from Graves' disease produce immune system antibodies that directly attack the thyroid gland. The attacking antibodies bind to the receptors on the thyroid gland that would normally be used by thyroid stimulating hormone, resulting in the stimulation and over-production of thyroid hormones (Mulryan, 2010). Once activated in this way, the thyroid responds with the typical enlargement seen in hyperthyroidism. The T3 type of thyroid hormone is produced in a larger proportion when compared to T4 than during normal thyroid function (Brent, 2008). T3 is the portion of thyroid hormone that is fast-acting and quickly absorbed by the body, meaning it has a greater effect on such body functions as heart rate than the T4 portion (Maas, 2007). The symptoms of Graves' disease are similar to those for other forms of hyperthyroidism but also include eyelid lag and and elevated upper eyelid, making the patient blink less frequently and appear to be staring with wide eyes (Hall, 2011; McCance et al., 2010). Pathophysiology As is commonly true with endocrine disorders, the increased levels of thyroid hormone result in detrimental effects on nearly all of the body's systems. The presence of high amounts of thyroid hormone in the body affects the ability of the cells to metabolize carbohydrates, proteins, and fats. Glucose absorption is increased, while sensitivity to insulin is decreased. The loss of lean body mass commonly seen in hyperthyroid patients is due to the rate of protein breakdown exceeding the rate of protein synthesis, while the loss of fat body mass is due to the increased rates of movement and breakdown of fats. The rate of excretion for cholesterol especially is increased. The combination of these factors can leave the patient malnourished and underweight, no matter the patient's caloric intake (Gutierrez, 2008). The increased amounts of thyroid hormone in the bloodstream have a significant effect on the heart and the cardiovascular system. The receptors on the heart muscle responsible for heart rate appear in increased numbers, and also become more sensitive, resulting in an elevated heart rate. The volume of blood moved by the heart per beat is increased, leading to a greater volume of blood in the peripheral cardiovascular system and a higher systolic blood pressure (Gutierrez, 2008). These changes can result in an enlargement of the heart, fibrillation, and heart failure, and are often correlated to an increased risk of stroke in elderly patients. Thankfully, this type of co-morbidity is less commonly seen with Graves' disease than with other causes of hyperthyroidism, and so affect a smaller portion of patients with the condition than would otherwise be expected (Biondi & Kahaly, 2010). Hyperthyroidism in Graves' disease specifically has ramifications for the sensory and peripheral organs, most notably the eyes and skin. Not all patients with Graves' disease report symptoms of the eyes, but imaging shows that nearly all hyperthyroid patients have some level of sub-clinical optical symptoms. Also, patients that show the ocular symptoms of Graves' disease generally turn out to suffer from a sub-clinical level of thyroid dysfunction. The same results occur for skin symptoms with further studies showing sub-clinical changes in many patients who are not noted to have that type of disease progression. The eye symptoms, especially the highly noticeable protrusion of the eyeball, are due to increases in the fat and muscle tissue surrounding the eye and the swelling of those tissues within the eye socket. This can eventually lead to neuropathy in the optic nerve and damage to the surrounding tissue The dermatological symptoms of Graves' disease are much less commonly seen at a clinical level, but generally also involve tissue swelling, as well as keratinosis (Bahn, 2003). Hyperthyroidism obviously also has deleterious effects on the thyroid gland itself, due to the increasing size and cell count. Depending on the ultimate cause of the thyroid dysfunction, various mechanisms will lead to folding of the cell matrix and an expansion in size of the gland. The stress that this puts on the cells within the gland, as well as the stress of significant over-production can eventually even lead to hypothyroidism, as the cells of the thyroid shut down and stop producing thyroid hormone entirely (McCance et al., 2010). Best Practice Treatment Guidelines Best practice for hyperthyroidism involves initially confirming the diagnosis of hyperthyroidism, as it can sometimes mimic the symptoms of other conditions, then determining the ultimate cause of the condition as this will affect prognosis and course of treatment. Due to the dangerous nature of many of the treatments and tests for hyperthyroidism, even the initial diagnosis process should use care. For example, one test for hyperthyroidism is a test of iodine uptake by the thyroid through the use of a radioactive iodine scan. However, there are obvious repercussions to the use of radioactive medications, and so this test does not need to be used if a patient presents with hyperthyroidism and symptoms consistent with Graves' disease. Instead, the medical professional in this case should simply begin treatment for Graves' disease and monitor the patient for their response to the treatment (Bahn et al., 2010). Since the test is useful for evaluating between several other types of hyperthyroidism, though, radioactive iodine scans are generally otherwise appropriate. In order to best protect patient safety, any co-morbid conditions or illnesses should be treated before the evaluation test, as the effect of hyperthyroidism for a brief period longer is less dangerous than the possible side effects of the radioactive iodine with a co-morbidity. Additionally, there should be absolute certainty that the patient is not pregnant, for obvious reasons (Bahn et al., 2010). The treatments for hyperthyroidism include continued dosage with radioactive iodine, the use of antithyroid medications, or the surgical removal of the thyroid (Bahn et al., 2010). All of these treatment options have serious side effects for the patient, and so the patient's desires and medical history as well as the current literature on the topic should be carefully considered before deciding on a specific mode of treatment. All three methods are well-researched, as they have been used for between fifty and one hundred years, and so there is plenty of data to analyze for these considerations (Hegedüs, 2009). Summary Diseases of the thyroid are not uncommon, especially among women and the elderly. One category of thyroid disorder is those diseases that result in over-production of thyroid hormones by the gland, known as hyperthyroidism. Hyperthyroidism results in a production rate of thyroid hormones that is five to fifteen times higher than normal, and greatly increases the basal metabolic rate of the patient. This can be caused by disease of the thyroid itself, a systemic auto-immune disease, or as a secondary result of a different endocrine disorder; the most common cause of hyperthyroidism is Graves' disease. Symptoms of the overactive thyroid include unintentional weight loss of both lean and fat mass, anxiety, increased and irregular heart rate, low heat tolerance, appetite changes, and fatigue. Graves' disease presents with these symptoms as well as eyelid lag and protrusion of the eyeball. Hyperthyroidism affects the endocrine system, resulting in changes in metabolic rate and nutritional uptake, the cardiovascular system, the eyes, the skin, and the thyroid gland itself. Evidence-based practice, when applied to the treatment of hyperthyroidism to help with these issues, means taking the dangers of the available treatments into careful consideration when deciding a treatment modality. References American Academy of Family Physicians. (2011). Subclinical hyperthyroidism: What it means to you. American Academy of Family Physicians. Retrieved from http://familydoctor.org Bahn, R. S. (2003). Pathophysiology of Graves’ Ophthalmopathy: The Cycle of Disease. Journal of Clinical Endocrinology & Metabolism, 88(5), 1939 -1946. doi:10.1210/jc.2002- 030010 Bahn, R. S., Burch, H. B., Cooper, D. S., Garber, J. R., Greenlee, M. C., Klein, I., Laurberg, P., et al. (2010). Hyperthyroidism: Management Guidelines of the American Thyroid Association and American Association of Clinical Endocrinologists. American Thyroid Association and American Association of Clinical Endocrinologists. Retrieved from http://www.eurospe.org/clinical/Docs/ATA- AACEHyperthyroidismManagementGuidelines2010.pdf Biondi, B., & Kahaly, G. J. (2010). Cardiovascular involvement in patients with different causes of hyperthyroidism. Nat Rev Endocrinol, 6(8), 431-443. doi:10.1038/nrendo.2010.105 Brent, G. A. (2008). Graves’ Disease. New England Journal of Medicine, 358(24), 2594-2605. Retrieved from nejm.org Fineout-Overholt, E., Stillwell, S. B., Williamson, K. M., Cox, J. F., & Robbins, B. W. (2010). Teaching evidence-based practice in academic settings. Evidence-Based Practice in Nursing & Healthcare: A Guide to Best Practice. Lippincott Williams & Wilkins. Gutierrez, K. (2008). Pharmacotherapeutics: Clinical reasoning in primary care (2nd ed.). St. Louis, Missouri: Saunders/Elsevier. Hall, J. E. (2011). Guyton and Hall Textbook of Medical Physiology (12th ed.). Philadelphia  PA: Saunders/Elsevier. Hegedüs, L. (2009). Treatment of Graves’ Hyperthyroidism: Evidence-Based and Emerging Modalities. Endocrinology & Metabolism Clinics of North America, 38(2), 355-371. doi:10.1016/j.ecl.2009.01.009 Maas, D. (2007, April). Thyroid Disease Can Cause Fatigue, Weight Gain and More. Retrieved from http://www.froedtert.com/HealthResources/ReadingRoom/EveryDay/Jan- April2007Issue/ThyroidDisease.htm McCance, K. L., Huether, S. E., Brashers, V. L., & Rore, N. S. (2010). Pathophysiology: The biologic basis for disease in adults and children (6th ed.). Maryland Heights, MS: Mosby/Elsevier. Mulryan, C. (2010). Disorders of the thyroid function. British Journal of Healthcare Assistants, 04(05), 218-222. Read More