A clinical reasoning group is reviewing the diagnostic utility of radioactive iodine uptake (RAIU) scanning for differentiating the etiologies of thyrotoxicosis. Match each thyroid disorder with its classic radioactive iodine uptake scan pattern.
- Graves diseaseDiffusely increased and homogeneous uptake
- Toxic multinodular goiterHeterogeneous pattern with multiple focal areas of increased uptake
- Subacute granulomatous thyroiditisDiffusely decreased (less than 5 percent) uptake
- Toxic adenomaSingle area of intense uptake with suppression of the surrounding tissue
Answer
Graves disease matches with diffusely increased uptake. Toxic multinodular goiter matches with multiple focal areas of increased uptake. Subacute granulomatous thyroiditis matches with diffusely decreased uptake. Toxic adenoma matches with a single area of intense uptake.
The correct matches represent the classic physiological behavior of the thyroid gland under different disease states. Graves disease uniformly activates the gland. Toxic multinodular goiter has multiple active nodules. Subacute thyroiditis involves cellular destruction, leaking hormone without new synthesis. A toxic adenoma has one active nodule that suppresses the rest of the healthy gland.
Step-by-Step Solution
Key Concept
Radioactive iodine uptake (RAIU) scan patterns in thyrotoxicosis