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Subclinical Hypothyroidism - Should we treat? (CQC)

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Subclinical Hypothyroidism - Should we treat? (CQC)

  1. 1. Should We Treat Subclinical Hypothyroidism? CQC Alap Shah Med/Peds PGY-1
  2. 2. History / Physical <ul><li>41 y/o Male with PMHx DM II, HTN, ED presents for f/u </li></ul><ul><ul><li>Has continued problems with glycemic control with sugars 140-160s, problems with ED despite meds </li></ul></ul><ul><ul><li>Had lost 10-15 lbs in 3 months – diet, exercise, but still felt it was “difficult to lose weight” </li></ul></ul><ul><li>FHx: “two sisters, one hypothyroid, one hyperthyroid” </li></ul><ul><li>Meds: Glipizide, Sildenafil, Metformin </li></ul><ul><li>PE: normal – no edema, no thyromegaly/nodularity, no arrhythmia, no obesity </li></ul>
  3. 3. Labs <ul><li>A1c – 14.5 (11/4/07), 9.6 (8/7/08) </li></ul><ul><li>TSH – 10.29 (8/7/08) (nml 0.4 - 4.4) </li></ul><ul><li>Anti TPO Ab – 1673.7 (nml < 9) </li></ul><ul><li>Free T4 – 1.1 (nml 0.8 – 1.7) </li></ul><ul><li>Testosterone – normal </li></ul><ul><li>Lipids – Low HDL, High LDL, Normal TG </li></ul>
  4. 4. Next Step <ul><li>Would you… </li></ul><ul><ul><li>A. Start Levothyroxine therapy </li></ul></ul><ul><ul><li>B. Monitor with TSH every 6 – 12 months </li></ul></ul><ul><ul><li>C. Follow clinically </li></ul></ul><ul><ul><li>D. Order additional tests </li></ul></ul>
  5. 5. Subclinical Hypothyroidism <ul><li>State in which TSH is mildly elevated, indicating mild thyroid failure, but normal serum levels of T3 and T4 </li></ul><ul><li>Most commonly caused by autoimmune thyroiditis, as in this patient </li></ul><ul><li>By most studies, ~ 4 – 18% of patients with SH per year develop overt hypothyroidism </li></ul><ul><ul><li>Increased likelihood if Ab+, TSH>20, Hx radiation, chronic Li therapy </li></ul></ul><ul><li>Small amount of patients (not quantified) do recover normal thyroid function </li></ul>
  6. 6. Etiologies of (Non-Central) Hypothyroidism <ul><li>Chronic Autoimmune Thyroiditis </li></ul><ul><li>Subacute Postpartum Thyroiditis </li></ul><ul><li>Iodine Deficiency, Excess </li></ul><ul><li>Thyroid surgery, I-131 exposure </li></ul><ul><li>External Irradiation </li></ul><ul><li>Infiltrative Disorders </li></ul><ul><ul><li>Sarcoid, Hemochromatosis, Leukemia, Lymphoma, Amyloid, TB, P jiroveci </li></ul></ul><ul><li>Drugs </li></ul><ul><ul><li>Lithium, Amiodarone, IFN-alpha, IL-2 </li></ul></ul>
  7. 7. When to Suspect SH <ul><li>Symptoms </li></ul><ul><ul><li>May be asymptomatic </li></ul></ul><ul><ul><li>Can have vague complaints including fatigue, depression, weakness, sleep disturbance, memory problems, constipation, menstrual irregularities </li></ul></ul><ul><li>Signs </li></ul><ul><ul><li>May have no physical abnormalities </li></ul></ul><ul><ul><li>Skin/hair changes, reflex delay, ataxia, hyperlipidemia, nonpitting edema, hoarseness, bradycardia, hypothermia </li></ul></ul>
  8. 8. Initial Lab Evaluation <ul><li>What labs to order for workup and followup for subclinical hypothyroidism? </li></ul><ul><ul><li>TSH if any of the previously mentioned symptoms, or high suspicion with strong family history </li></ul></ul><ul><ul><ul><li>TSH is 98% sensitive and 92% specific for thyroid disease </li></ul></ul></ul><ul><ul><ul><li>TSH is the definitive screening and monitoring lab for (non-central) thyroid disease </li></ul></ul></ul><ul><ul><li>If abnormal, repeat in 1 month and check Free T4 </li></ul></ul>
  9. 9. Initial Lab Evaluation <ul><li>Annals of Clinical Biochem (2006) </li></ul><ul><ul><li>Indications for Anti TPO Ab: </li></ul></ul><ul><ul><ul><li>Patients with subclinical hypothyroidism </li></ul></ul></ul><ul><ul><ul><ul><li>TSH from 4 - 10, normal Free T4 </li></ul></ul></ul></ul><ul><ul><ul><li>Goiter, regardless of TSH or Free T4 </li></ul></ul></ul><ul><ul><ul><li>New onset thyrotoxicosis </li></ul></ul></ul><ul><ul><li>No indication to follow Ab once positive </li></ul></ul>
  10. 10. Treatment <ul><li>Recommendations vary: </li></ul><ul><ul><li>USPSTF (2004) </li></ul></ul><ul><ul><li>Consensus Conference Panel on Subclinical Thyroid Disease (2004) </li></ul></ul><ul><ul><li>Endocrinology Clinics (2004) </li></ul></ul><ul><ul><li>American Association of Clinical Endocrinologists Thyroid Task Force </li></ul></ul><ul><ul><li>Various other groups, studies </li></ul></ul>
  11. 11. Treatment <ul><li>USPSTF (2004) </li></ul><ul><ul><li>Treatment for subclinical hypothyroidism reduces symptoms of patients with history of Graves’ and TSH > 10 </li></ul></ul><ul><ul><li>Insufficient evidence for recommendations from other trials </li></ul></ul><ul><ul><li>Most trials found there was no effect on lipid levels </li></ul></ul>
  12. 12. Treatment <ul><li>Consensus Conference Panel on Subclinical Thyroid Disease (2004) </li></ul><ul><ul><li>For TSH between 4.5 and 10, no treatment </li></ul></ul><ul><ul><ul><li>Repeat TSH at 6 – 12 month intervals for change </li></ul></ul></ul><ul><ul><ul><li>For TSH > 10, evidence inconclusive – agreement with USPSTF </li></ul></ul></ul>
  13. 13. Treatment <ul><li>Endocrinology Clinics (2004) </li></ul><ul><ul><li>Good evidence that treatment prevents overt hypothyroidism, but no convincing evidence that early treatment beneficial </li></ul></ul><ul><ul><li>Improvement in lipid panel, but no hard studies on mortality benefits </li></ul></ul>
  14. 14. Treatment <ul><li>National Guideline Clearinghouse (JAMA 2004) </li></ul><ul><ul><li>For TSH between 4.5 and 10, no treatment </li></ul></ul><ul><ul><ul><li>Follow up with TSH every 6 – 12 months </li></ul></ul></ul><ul><ul><ul><li>Based on no clear cut benefit to these patients </li></ul></ul></ul><ul><ul><ul><li>However, report stated that treatment may prevent signs and symptoms in those that do progress </li></ul></ul></ul>
  15. 15. Treatment ... And Followup <ul><li>AACE Thyroid Task Force (2006) – Treatment Guidelines </li></ul><ul><ul><li>Start at 25 – 50 micrograms / day </li></ul></ul><ul><ul><li>Repeat TSH 6 – 8 weeks after starting treatment </li></ul></ul><ul><ul><li>Titrate dose to keep TSH between 0.3 – 3 </li></ul></ul><ul><ul><li>Once TSH stable, check levels and examine patient annually </li></ul></ul>
  16. 16. Next Step <ul><li>Would you… </li></ul><ul><ul><li>A. Start Levothyroxine at 25-50 mcg/day </li></ul></ul><ul><ul><li>B. Monitor with TSH every 6 – 12 months </li></ul></ul><ul><ul><li>C. Follow clinically </li></ul></ul><ul><ul><li>D. Order additional tests </li></ul></ul><ul><ul><li>No definitive answer. Most importantly, remember to treat patient and not just the lab values. </li></ul></ul>
  17. 17. When to Consult Endocrinology <ul><li>AACE recommends endocrine consult if: </li></ul><ul><ul><li>< 18 yrs </li></ul></ul><ul><ul><li>Unresponsive to therapy </li></ul></ul><ul><ul><li>Pregnant </li></ul></ul><ul><ul><li>Cardiac history </li></ul></ul><ul><ul><li>Presence of goiter or nodules </li></ul></ul><ul><ul><li>Concurrent endocrine disease </li></ul></ul>
  18. 18. Patient <ul><li>Due to initial SH, started Synthroid 25mcg daily x 2 wks, then 50mcg daily until follow up </li></ul><ul><li>After TPO was +, called and instructed to continue regimen </li></ul><ul><li>Follow up scheduled, pending… </li></ul>
  19. 19. References <ul><li>Devdhar et al. Hypothyroidism. Endocrinol Metab Clin N Am. 2007; 36:595-615. </li></ul><ul><li>AACE Thyroid Task Force. Medical Guidelines For Clinical Practice For The Evaluation And Treatment Of Hyperthyroidism And Hypothyroidism. Endocrine Practice. 2006; 8:6. </li></ul><ul><li>Herrick. Subclinical Hypothyroidism. American Family Physician. 2008; 77:7. </li></ul><ul><li>Surks et al. Subclinical thyroid disease: scientific review and guidelines for diagnosis and management. JAMA.  2004; 291(2). </li></ul>
  20. 20. References <ul><li>Miller and Rogers. Which Lab Tests Are Best When You Suspect Hypothyroidism? Clinical Inquiries, Family Physicians Inquiries Network. 2008; 57:9. </li></ul><ul><li>Downs and Meyer. How Useful Are Autoantibodies When Diagnosing Thyroid Disorders? Clinical Inquiries, Family Physicians Inquiries Network. 2008; 57:9. </li></ul><ul><li>Sinclair. Clinical And Laboratory Aspects Of Thyroid Antibodies. Ann Clin Biochem. 2006; 43: 173-183. </li></ul><ul><li>USPSTF. Screening For Thyroid Disease: Systematic Evidence Review. 2004. </li></ul>

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