273 SUPPRESSION TEST (WERNER): This test differentiates thyrotoxicosis from other ses of raised uptakes, e.g., iodine deficiency and the autonomous thyroid nodules. This test dangerous in elderly patients and those with heart failure as there always remains a potential of inducing transient hyperthyroidism. test available at pre HORMONE (TSH) The The initial uptake is measured. 40 µg of tri-iodothyronin is given 8 hourly by mouth for Sdays after which the uptake is repeated. T3 is used because of its more rapid effect and its borter half-life. Considerable suppression in thyroid uptake is noted in the range of 50-80% by this amount of exogenous hormone. Slight suppression in the range of 10-20% is noted in mal level is absturotoxicosis, The TRH test gives similar information and has replaced the T3 suppression ein hyperthyroidiohithroid drug treatment for thyrotoxicosis, this test may be used as an indicator of remission nyperthy of the disease. A return to normal suppressibility in treated patients usually indicates remission abtotal thyroidectomy AXIS When est in centers where a radioimmunoassay of serum TSH is available. In patients who are on 1. THYROID SCAN: Scanning with a tracer dose will show which part of the gland is functioning wwwhich part is not functioning (hot or cold). Both "I and "mTc can be used. I scan can be abtained at 24 hours whereas "mTc scan is obtained at about 1/2 hour. It is not useful to scan roidism there isoroid nodule is an indication for surgery. Only histological examination can reveal whether hypothyroidism in case of suspected retrosternal goiter or (iii) ectopic thyroid tissue. A single non-functioning Many dresdenoma or a focal area of autoimmune thyroiditis If a nodule is autonomous most of the levodona. These motopes will accumulate in the nodule and the rest of the gland will show little activity. But if all enlarged glands, but it is helpful to scan the thyroid when (i) a solitary nodule is palpated, it is a carcinoma or one of other causes of nonfunctioning nodules such as a cyst, colloid-filled the nodules are functioning but not autonomous, both the nodules and the rest of the gland individual, the level of ick concentration of the 13. and ent in the diagnosis of cases of mild hyperby ic Graves' disease diagnosis of hypothymid he assessment of hacini inly used and "mir ( gy and short hall often Moreover Technet is not bound to se ni will take up the isotopes. Metastasis can be demonstrated by scanning the whole body of the patient but there should be no functional thyroid tissue as the thyroid cancer cannot compete with the normal thyroid tissue in the uptake of iodine. . Miscellaneous tests: These comprise the BMR, serum cholesterol, serum creatine, measurement of tendon reflexes, ECG, etc. Of these BMR and measurement of tendon reflexes may help in the diagnosis of hypothyroidism. Other tests are of little value. Radiography: This is helpful to diagnose the position of the trachea-whether displaced or narrowed. Straight X-ray is also helpful in diagnosing retrosternal goiter. In case of malignant thyroid, the bones (especially the if suspected to be secondary for evidence of metastasis. X-ray after barium swallow may indicate whether there is any pressure effect on the esophagus or not. goiter. Selective angiography can also differentiate between a functioning and nonfunctioning thyroid nodule. Moreover it may indicate presence of retrosternal Bone scan may be done to exclude early bony metastasis. Fine needle aspiration cytology (FNAC): This is an excellent, simple and quick test for thyroid cysts which can be performed as outpatient method. Thyroid conditions which may be diagnosed by this technique are thyroiditis, colloid nodule (quite common), benign tumors like follicular adenoma, follicular carcinoma, papillary carcinoma, anaplastic carcinoma, medullary carcinoma and lymphoma. Ultrasound: It has a value to differentiate between solid and cystic swellings. It also demonstrates impalpable nodules. But its value to diagnose malignancy is limited. CT and MRI: These newer methods have not yet proved themselves very helpful in detecting day-to-day thyroid disorders. These are still in the experimental stage. Simplified