Graves’ Disease on Thyroid Scan
Provided clinical image
Question
This thyroid scan shows a diffusely enlarged gland with homogeneously increased radiotracer uptake and no discrete nodules. A thyroid uptake measurement in this patient would most likely be elevated (>35% at 24 hours). This pattern is most consistent with:
- AMultinodular goiter
- BHashimoto's thyroiditis (early phase)
- CGraves' disease (diffuse toxic goiter)
- DSubacute thyroiditis
Show the answer and explanation
C. Graves' disease (diffuse toxic goiter)
Graves' disease produces diffuse, homogeneous thyroid enlargement with markedly increased radiotracer uptake and elevated 24-hour radioiodine uptake (typically >35%). It results from TSH receptor antibodies that chronically stimulate the gland. A multinodular goiter shows heterogeneous uptake with hot and cold areas. Hashimoto's thyroiditis usually has normal or decreased uptake with patchy distribution. Subacute thyroiditis shows very LOW uptake (damaged follicles release preformed hormone, suppressing TSH).
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