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Graves Disease Karan J. Walston Biology 003: Dr. Zigmond March 21, 2002 1 thyroid gland controls metabolism through the secretion of T4 and T3 hormones one of the largest glands in the endocrine system 2 T3 & T4 Function: secretion of t3 & t4 by thyroid is controlled by endocrine feedback system involving pituitary gland & the hypothalamus in the brain 3 Epidemiology discovered in Bath, England 1835 by Robert Graves affects approximately 3 out of 1000 people more prevalent in women & in families with a history of the disorder 4 graves’ disease can occur at any age, but is unusual before puberty most common in older adults 7:1 ratio predominance in women 5 What is Graves’ Disease ? autoimmune disease and the leading cause of hyperthyroidism mainly affects the thyroid gland can also affect the eyes and skin 6 What is an autoimmune disease? What initiates these autoimmune reactions? 7 autoimmune response occurs when the immune system incorrectly identifies parts of healthy cells in the body as “invaders” and produces antibodies to attack the cells 8 autoimmune disease with hyperthyroidism is when the goiter or thyroid gland are immunologically mediated results from the production of autoantibodies directed against the TSH (thyroid stimulating hormone) receptors on the thyroid follicular cells or thyroid gland antibodies attack these cells 9 2 types of auto-antibodies: TSI (thyroid simulating immunoglobins or TSH –receptor antibodies (TRAb) mimic the action of TSH, thereby inducing the hypersecretion of the thyroid hormone TGI (thyroid growth stimulating immunoglobulins) initiates the growth of thyroid cells or the thyroid gland 10 Autoimmune Reactions Triggered by: viruses or bacteria in genetically predisposed individuals certain strains of E.coli or Yersina entercolitica possess cell membrane TSH receptors emotional stress plays a big factor 11 Other Names for the Disease are: most common is Hyperthyroidism, not to be confused with Hypothyroidism toxic goiter parry disease basedow’s disease 12 Graves’ Disease Symptoms: nervousness irritability unexplained weight loss increased appetite diarrhea excessive sweating heat intolerance thyroid enlargement rapid pulse 13 Other Symptoms: about 50 % of patients have exophthalmos raised plaque like itchy skin on the legs rapid pulse is can result in cardiac failure=thyroid storm 14 Diagnosis: physical exam thyroid scan showing diffusely increase uptake of radioactive isotope (131I) to test thyroid function blood test for T4 & T3 – abnormally high 15 Treatments: radioactive iodine since 1939 treatment for hyperthyroidism has been radioactive iodine isotope (131I) antithyroid drugs thyroidectomy 16 Problems with Treatments: with radioactive iodine correct dosage underactive thyroid hormone pill radioactive materials 17 Anti-thyroid Drugs: 2 types: Propylthiouracil Thyroxine low success rate can cause leukemia high relapse rate 18 Surgery-Thyroidectomy removal of thyroid gland possible complications of voice box replacement hormone pill 19 Genetic Factors: genetics may play a role but inconclusive there is an association between the disease and the genes HLA or (human leucocyte antigen) B8, -DRw3, -Bw36 50% concordance found between identical twins 20 Hypothyroidism: underactivity of thyroid gland risk factors symptoms treatment 21 Recap: symptoms endocrinologist blood test radioactive iodine uptake treatment follow-up look for reoccurring symptoms hypothyroidism research www.thyroid.org 22 Questions: Can you have children with graves’ disease? How dangerous is radioactive iodine and can it be past to fetus? Does radioactive iodine isotope cause cancer? What are some other manifestations related to this disease? 23 References: Klein, I,Becker DV, Levey Gs. Treatment of Hyperthyroid Disease: Ann Intern Med. 1994 Aug 15; 121 14:28-18 Merck Medical Manual of Diagnosis and Therapy: Whitehouse Station, N.J. Merck & Co., inc 2000 http://www.nlm.nih.gov/medlineplus/ency http:/www.thyroid.org/publications http://www.sci.lib.uci.edu/hsg/Medical.html 24