الفهرس | Only 14 pages are availabe for public view |
Abstract Subclinical thyroid disorders are clinically inapparent disorders that are diagnosed by laboratory methods. Recent TSH assays helped greatly in diagnosing such disorders. Subclinical hypothyroidism (SCH) is defined as a persistently elevated serum TSH levels with normal or low normal levels of free T3 and T4 in the presence or absence of hypothyroid symptoms. The high TSH levels in this condition reflects the sensitivity of hypothalamo-pituitary axis to the small changes of circulating thyroxine levels which may be at the low end of normal. The prevalence of SCH is about 4.3 to 9 % of general population with much higher prevalence in women than men especially older women. In addition there is a strong association between positive thyroid peroxidase antibodies and elevated TSH levels. Screening of SCH should be performed among high risk groups including women older than 60 years, persons with previous radiation treatment of the thyroid gland, those with previous thyroid surgery or thyroid dysfunction, a family history of thyroid disease, or AF and those who have type 1 diabetes mellitus or a personal history of autoimmune disease. The importance of SCH emerges from its clinical implications. Some patients with SCH may have symptoms of the overt disease such as dry skin, cold intolerance and easy fatigability. These symptoms improve after treatment with thyroid hormones. |