Thyroid Disease Diagnosis, Treatment and Health Prevention: an Overview
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THYROID DISEASE DIAGNOSIS, TREATMENT AND HEALTH PREVENTION: AN OVERVIEW Jassin M. Jouria, MD Dr. Jassin M. Jouria is a medical doctor, professor of academic medicine, and medical author. He graduated from Ross University School of Medicine and has completed his clinical clerkship training in various teaching hospitals throughout New York, including King’s County Hospital Center and Brookdale Medical Center, among others. Dr. Jouria has passed all USMLE medical board exams, and has served as a test prep tutor and instructor for Kaplan. He has developed several medical courses and curricula for a variety of educational institutions. Dr. Jouria has also served on multiple levels in the academic field including faculty member and Department Chair. Dr. Jouria continues to serves as a Subject Matter Expert for several continuing education organizations covering multiple basic medical sciences. He has also developed several continuing medical education courses covering various topics in clinical medicine. Recently, Dr. Jouria has been contracted by the University of Miami/Jackson Memorial Hospital’s Department of Surgery to develop an e-module training series for trauma patient management. Dr. Jouria is currently authoring an academic textbook on Human Anatomy & Physiology. Abstract Management of the common forms of thyroid disease has undergone significant study and development, as evidenced by the latest guidelines to diagnose and treat the thyroid. Because the thyroid gland’s role is so pervasive in the body, it is important for clinicians to understand the common symptoms of various thyroid diseases, including those not so commonly known. The diagnosis, treatment and prevention of thyroid conditions are discussed. nursece4less.com nursece4lesscom nursece4less.com nursece4less.com 1 Policy Statement This activity has been planned and implemented in accordance with the policies of NurseCe4Less.com and the continuing nursing education requirements of the American Nurses Credentialing Center's Commission on Accreditation for registered nurses. It is the policy of NurseCe4Less.com to ensure objectivity, transparency, and best practice in clinical education for all continuing nursing education (CNE) activities. Continuing Education Credit Designation This educational activity is credited for 4 hours. Nurses may only claim credit commensurate with the credit awarded for completion of this course activity. Statement of Learning Need The thyroid gland is active in virtually every cell of the body, regulating cellular respiration, energy expenditure, overall metabolism, growth and development of cells and tissues. It is important to understand the symptoms of thyroid diseases, and to know the management and treatment of these conditions. Course Purpose To provide advanced learning for clinicians interested in the diagnosis, treatment and prevention of thyroid disease. nursece4less.com nursece4lesscom nursece4less.com nursece4less.com 2 Target Audience Advanced Practice Registered Nurses and Registered Nurses (Interdisciplinary Health Team Members, including Vocational Nurses and Medical Assistants may obtain a Certificate of Completion) Course Author & Planning Team Conflict of Interest Disclosures Jassin M. Jouria, MD, William S. Cook, PhD, Douglas Lawrence, MA, Susan DePasquale, MSN, FPMHNP-BC – all have no disclosures Acknowledgement of Commercial Support There is no commercial support for this course. Please take time to complete a self-assessment of knowledge, on page 4, sample questions before reading the article. Opportunity to complete a self-assessment of knowledge learned will be provided at the end of the course. nursece4less.com nursece4lesscom nursece4less.com nursece4less.com 3 1. The thyroid gland has been called the “Master Gland” because it a. produces parathormone. b. is a member of the hormone-responsive nuclear transcription factors superfamily. c. is active in virtually every cell of the body. d. plays a vital role in controlling calcium and phosphate levels. 2. True or False: Embryologically, the developing thyroid forms the floor of the pharynx, around the base of the tongue, descending the neck to its adult location. a. True b. False 3. The thyroid is supplied by the superior and inferior thyroid arteries, and on rare occasions, there is an additional artery known as the a. innominate artery. b. subclavian artery. c. deep artery. d. thyroidea ima. 4. Thyroid hormone is a. required for normal human growth and development. b. required for the regulation of metabolism in infants and adolescents. c. mostly active during the neonatal and pre-adolescent periods. d. primarily used for the production of iodine. 5. Thyroid hormone ____________ begins with the organification of iodide to iodine and then condensed onto tyrosine residues found on thyroglobulin protein. a. absorption b. secretion c. synthesis d. conversion nursece4less.com nursece4lesscom nursece4less.com nursece4less.com 4 Introduction The thyroid gland has been called the Master Gland because it is active in virtually every cell of the body, regulating cellular respiration, energy expenditure, overall metabolism, growth and development of cells and tissues. Because the thyroid gland’s role is so pervasive in the body, it is important to understand the symptoms of the types of thyroid disease such as hypothyroidism and hyperthyroidism, and to know the management and treatment of these conditions. Anatomy Of The Thyroid The anatomy of the thyroid gland is reviewed in this first section of this course to provide a basic understanding of thyroid structures, hormones, and the blood and nerve supply. There are various ways to evaluate the thyroid gland to rule out pathology, which is covered in later course sections and as well as in subsequent course series on thyroid disease, diagnostic testing, pathology and treatment.1-6 The thyroid gland consisting of two lobes and connected by an isthmus, is located at the anterior neck, just below the cricoid cartilage, roughly at the level of C5 to T1 and overlaying the second to the fourth tracheal rings. The parathyroid glands are four small glands usually located at the posterior portions of the thyroid and which produce parathyroid hormone (PTH) and play a vital role in controlling calcium and phosphate levels. The parathyroid glands share blood supply, lymphatic drainage and venous supply with the thyroid. Embryologically, the developing thyroid forms the floor of the pharynx, around the base of the tongue, descending the neck in the adult. As it descends during the 4th to 8th week of gestation, the thyroglossal duct, nursece4less.com nursece4lesscom nursece4less.com nursece4less.com 5 a duct that has regressed in the adult, guides the thyroid gland. In about half of individuals, however, the distal portion of the thyroglossal duct remains, essentially as an extra lobe of thyroid tissue with no apparent clinical significance. Thyroglossal cysts, resulting from persistent sections of the thyroglossal duct, occur relatively commonly. These can be diagnosed with ultrasonography. The most common complications of a thyroglossal cyst are infection and malignancy, occurring in 1 to 4% of individuals. The mass and dimensions of the thyroid can vary, but tends to be slightly heavier in females, enlarging during monthly cycles and in pregnancy. In both males and females, the mass is 25 – 30 gm with each lobe 50 – 60 mm. The thyroid gland is principally enervated by the autonomic nervous system with parasympathetic fibers from the vagus, and sympathetic enervation is derived from the superior, middle and inferior ganglia of the sympathetic trunk. The fibers enter the gland alongside the vasculature and appear to primarily regulate perfusion rates. The basic structural unit of the thyroid are the follicles, formed by multiple septae, dividing the gland into lobes and lobules, with the follicles consisting of a layer of epithelial cells surrounding a colloid- nursece4less.com nursece4lesscom nursece4less.com nursece4less.com 6 filled center surrounded by fenestrated capillaries, lymphatic vessels and sympathetic nerves. Within the colloid, iodothyroglobulin (the precursor of the thyroid hormones) can be found. The principle or follicular cells secrete the colloid. The parafollicular cells, embedded within the basal laminae and adjacent to the follicles secrete calcitonin (a hormone that regulates calcium in the blood). Vascular and Lymphatic Anatomy of the Thyroid The superior and inferior thyroid arteries supply the thyroid. Relatively rarely, there is an additional artery, the thyroidea ima that originates from the aortic arch or the innominate artery, entering the gland at the inferior border of the isthmus. The arterial supply has numerous anastomoses that are present both ipsilaterally and contralaterally. The superior thyroid artery is the first branch (anterior) off the external carotid. After branching, it descends laterally to the larynx, posterior to the omohyoid and sternohyoid muscles. It then runs superficially along the anterior border, delivering a deep branch before curving towards the isthmus. The superior thyroid artery then anastomoses with the contralateral artery. The inferior thyroid artery branches off from the thyrocervical trunk (a branch of the subclavian artery). After branching off, the inferior thyroid artery ascends superiorly and then laterally, entering the tracheoesophageal groove posterior to the carotid sheath. Sub-branches then enter along the posterior portion of the lobes. The recurrent