Thyroid Diagnostic Procedures, Treatment and Prevention
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THYROID DIAGNOSTIC PROCEDURES, TREATMENT AND PREVENTION 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 symptoms of various thyroid diseases. The diagnosis and treatment of thyroid conditions are discussed. 1 nursece4less.com nursece4less.com nursece4less.com nursece4less.com 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 3.5 hours. Nurses may only claim credit commensurate with the credit awarded for completion of this course activity. Pharmacology content is 0.5 hours (30 minutes). 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, management and treatment of thyroid diseases. 2 nursece4less.com nursece4less.com nursece4less.com nursece4less.com 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 3 nursece4less.com nursece4less.com nursece4less.com nursece4less.com 1. ______________ or T4 (containing four iodine atoms) is the primary thyroid hormone secreted by the thyroid gland. a. Thyroid stimulating hormone b. Thyroxine c. Triiodothyronine d. Thyroglobulin 2. True or False: The thyroid stimulating hormone (TSH) test is often the only test ordered by clinicians when thyroid disease is suspected, and this can lead to misdiagnosis. a. True b. False 3. Thyroid stimulating hormone (TSH) is released by the a. parathyroid. b. thymus. c. pituitary gland. d. thyroidea ima. 4. What is the consensus regarding the diagnostic limits for thyroid stimulating hormone (TSH) that would indicate thyroid failure and hypothyroidism? a. TSH >10 mIU/L b. TSH ≥ 4 mIU/L c. TSH ≥ 3 mIU/L d. None of the above 5. Decreased thyroid stimulating hormone (TSH) levels are seen in a. primary hypothyroidism. b. TSH-producing tumors. c. Hashimoto’s thyroiditis. d. primary hyperthyroidism. 4 nursece4less.com nursece4less.com nursece4less.com nursece4less.com Introduction Laboratory testing to diagnose thyroid disease makes use of a number of blood test and imaging procedures to hopefully early identify and manage medical treatment. Many tests utilize direct measurement of specific analytes while others are calculated values. Thyroxine or T4 (containing four iodine atoms) is the primary thyroid hormone secreted by the thyroid gland. Thyroid stimulating hormone (TSH) is released by the pituitary gland depending on the level of T4 recognized by the pituitary; the more T4 the less the TSH level and the less the T4 the higher the TSH level. While the TSH level has been the gold standard to diagnose and treat thyroid disease, there are other diagnostic tests that help guide treatment. Often clinicians will rely solely on the TSH, which can lead to misdiagnosis. The varied tests for thyroid disease and treatment recommendations are emphasized in the initial sections of this course. Thyroid Hormones And Testing: A Review The major thyroid hormone secreted by the thyroid gland is thyroxine. Thyroxine is called T4 because it contains four iodine atoms. Thyroxine converts to triiodothyronine (T3) by the removal of one iodine atom. It is this conversion process (T4 to T3) that makes thyroxine effective. Thyroxine (T4) circulates in the blood in two forms: bound or free. When T4 is bound to proteins, i.e., thyroglobulin, it cannot enter the various tissues that need thyroid hormone. Free T4 (fT4), on the other hand, does enter the various target tissues to exert its effects. This section identifies and explains the role of varied thyroid hormones and known disease, drug and other chemical interactions affecting thyroid processes and health.1-3,42-47,106,107 5 nursece4less.com nursece4less.com nursece4less.com nursece4less.com Thyroid Stimulating Hormone The thyroid-stimulating hormone (TSH) is commonly the first — and often only — test ordered when thyroid disease is suspected. In most labs, normal adult values range from 0.4-5mIU/L. By day 3, neonatal ranges are 3-20µIU/L. TSH (thyrotropin) is secreted diurnally. In addition, TSH secretion can be affected by age, gender, ethnic background and overall health. Third generation TSH assays can detect TSH with a coefficient of variation of 20% down to a level of approximately 0.01 mIU/L. It should be noted that TSH levels will begin to increase before fT4 levels begin to decrease.2 There is some disagreement regarding diagnostic limits for TSH. For many years and for many clinicians, TSH >10 mIU/L was indicative of thyroid failure and hypothyroidism. The National Academy of Clinical Biochemistry has, however, recommended 4 mIU/L as an upper limit, while the American Association of Clinical Endocrinologists has set the upper limit at 3 mIU/L. Other professional groups have suggested even lower values such as 2.5 mIU/L. There is a growing consensus that ‘one size does not fit all’ and that individual patient responses must be taken into account during treatment. In addition, there is currently no accepted reference measurement procedure (RMP) for the TSH assay, meaning there are significant variations from lab to lab and between different assay manufacturers. Increased TSH levels are seen in the table below. 6 nursece4less.com nursece4less.com nursece4less.com nursece4less.com Various Upper Levels of Normal for TSH Upper Level of Normal National Academy of Clinical 2.5 mIU/L with no evidence of thyroid Biochemists (NACB) disease National Health and Nutrition 4.5 mIU/L with no evidence of thyroid Examination Survey III, NHANES disease (self-reported) (Disease Free) National Health and Nutrition 4.12 mIU/L with no evidence of thyroid Examination Survey III, NHANES disease (self-reported), negative for anti- (Reference Population) thyroid antibodies, not pregnant or using estrogen contraceptives, androgens or lithium Hanford Thyroid Disease Study 4.10 mIU/L with no evidence of thyroid disease, negative for anti-thyroid antibodies, normal US (no nodules or evidence of thyroiditis) Pregnancy, 1st trimester 2.0-2.5 mIU/L Pregnancy, 2nd trimester 3.0 mIU/L Pregnancy, 3rd trimester 3.5 mIU/L Increased TSH levels may be found in the following conditions: • Adults, children and neonates with primary hypothyroidism • TSH-producing tumors • Hashimoto’s thyroiditis • Thyrotoxicosis due to a pituitary tumor • TSH antibodies • Hypothyroid patients receiving insufficient replacement hormone or hyperthyroid patients receiving excessive replacement hormone • Hypothermia in infants and children 7 nursece4less.com nursece4less.com nursece4less.com nursece4less.com Decreased TSH levels are seen in: • Primary hyperthyroidism • Secondary, tertiary hypothyroidism • Euthyroid Sick Syndrome • Hypothyroid patients receiving excessive replacement hormone or insufficient replacement hormone in those treated for hyperthyroidism Drugs, pregnancy, estrogen