Thyroid & Adrenal
A 25 year old female with features of thyro-toxicosis T4 -140 IU, TSH - 0.04 IU, 2 x 2 cm thyroid nodule is found, what is the next investigation
a. Single Thyroid Nodule with features of thyrotoxicosis indicates SNG Hyperfunctioning Adenoma Hyperfunctioning adenomas become independent of thyroid stimulating hormone (TSH) control and secrete thyroid hormone autonomously, which results in clinical hyperthyroidism.
b. The elevated thyroid hormone levels ultimately diminish TSH levels severely and thus depress function of the remaining normal thyroid gland.
c. An isolated focus of increased uptake on a thyroid scan is virtually diagnostic of a hyperfunctioning adenoma.
d. Carcinomas usually display diminished uptake and are called "cold" nodules. Graves' disease would probably manifest as a diffusely hyperactive gland without nodularity.
Multinodular goiter would display many nodules with varying activity.
a. Solitary nodules in a patient with hyperthyroidism are an indication for RAI scan, which generally distinguishes toxic adenoma from graves disease.
b. However, graves disease may occasionally be unilateral owing to agenesis of the contralateral lobe, SO additional studies with antithyroid antibodies may be helpul.
c. A hot nodule is usually benign, but is resected to cure the hyperthyroidism.