May 2008 - bcps

Approach to Subclinical Thyroid DiseaseSR SutradharEvaluation of Subclinical Hypothyroidism :thyroid disease should be considered, specially forsymptomatic hypothyroidism. 15 if there is clear symptomatic benefit.those older than 60 years or with risk factors such aswomen with a family history of thyroid disease, priorthyroid dysfunction, symptoms suggestive ofThe TSH measurement should be repeated along withan FT 4measurement at a minimum of 2 weeks, but nolonger than 3 months, after the initial assessment.hyperthyroidism or hypothyroidism, abnormalIf a high serum TSH concentration is confirmed onthyroid gland on examination, type 1 diabetes, or arepeat testing and serum FTpersonal history of autoimmune disorder. 34is within the referencerange, the patient should be evaluated for signs andThe panel found insufficient evidence to recommendfor or against screening pregnant women or womenplanning a pregnancy. 3symptoms of hypothyroidism, previous treatment forhypothyroidism, thyroid gland enlargement, or familyhistory of thyroid disease. Lipid profiles should beThe American College of Physicians (1998),reviewed. Women who are pregnant or hope to becomerecommends screening for women older than 50pregnant in the near future deserve special consideration.years who have symptoms consistent with thyroiddisease. 8Subclinical Hypothyroidism:EtiologyAnti-thyroid peroxidase(Anti-TPO) antibodies are tobe measured because the presence of anti-TPOantibodies predicts a higher risk of developing overthypothyroidism (4.3% per year vs 2.6% per year inantibody-negative individuals). 16Hashimoto’s thyroiditis , protracted recovery fromacute thyroiditis, early hypothalamic disorder,inadequate levothyroxine replacement therapy in apatient with known hypothyroidism.‘ 3Risks of Treating Subclinical Hypothyroidism:The potential risks of therapy are limited to thedevelopment of subclinical hyperthyroidism, whichConsequences of Untreated Subclinicalmay occur in 14% to 21% of individuals treated withlevothyroxine. 17Hypothyroidism:Treatment:Serum lipid levels in subclinical hypothyroidism(SCH) have been reported as either normal 9 or Subclinical Hypothyroidism With Serum TSH of 4.5elevated 10 . In the Tromso study, low densityto 10 mIU/L.lipoprotein – cholesterol (LDL-C) levels were ● Routine levothyroxine treatment is notsignificantly higher. 10 In Suita study, no significantassociation was observed between sub clinicalthyroid dysfunction and lipid metabolism. The suitastudy reported that SCH was associated with lowerrecommended for patients with TSH levelsbetween 4.5 and 10 mIU/L, but thyroid functiontests should be repeated at 6- to 12-monthintervals to monitor for improvement orfasting blood glucose ( FBG). 11worsening in TSH level. 3 Very recently a studyshowed that patient with subclinicalSCH patients have impaired endothelial function,hypothyroidism with TSH > 4 mIU and FTnormal / depressed systolic function, left ventricular4innormal range obtained improvement in theirdiastolic dysfunction at rest, and systolic and diastolicdysfunction on effort. 12cardiovascular rick factor profile and reducedIn two studies, positivetiredness after treatment with Levothyroxine. 18association between arterial stiffness & SCH has beenThyroxin therapy for TSH level between 4.5- 10reported. 12, 13 But no significant association betweenmIU/L should be reserved for patients who haveSCH and intima-media thickness( IMT) was observed goitre, women that are anticipating pregnancy orin Suita study 11 , which suggests that SCH might notbe related to an increased risk of atherosclerosis.Patient may exhibit the feature of systemicare pregnant, patient with depression or dipolardisorder or TPO antibody positive. Thyroxinetherapy may be considered in patients withhypothyroid symptoms 6,14 , neuropsychiatric symptoms of hypothyroidism who have TSHsymptoms 6,14 and may progress to overt, level between 4.5-10 mIU/L and continued only92