Endocrinology: low radioiodine uptake thyrotoxicosis: practice question

A General Medicine question in the style of the NEET PG paper. Answer it first, then read why the right option is right and why each of the others is wrong.

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General Medicine · Endocrinology: low radioiodine uptake thyrotoxicosis

Sample item

A woman has thyrotoxic symptoms, suppressed TSH and a 24-hour radioiodine uptake of 1 percent. Thyroglobulin is undetectable. What is the likely cause?

Original practice item, not a recalled exam question. Nothing here is recorded.

The answer and the reasoning

B. Factitious thyrotoxicosis from exogenous thyroid hormone

Low radioiodine uptake with thyrotoxicosis occurs with thyroiditis, exogenous hormone intake and struma ovarii. A low thyroglobulin points to exogenous hormone because the gland is not releasing stored hormone. Graves disease and toxic nodular disease show high or normal uptake.

Option by option

  • A. Toxic adenoma

    Toxic adenoma shows a hot nodule.

  • B. Factitious thyrotoxicosis from exogenous thyroid hormone (correct)

    Correct. Low uptake with low thyroglobulin points to exogenous hormone.

  • C. Graves disease

    Graves disease shows diffusely high uptake.

  • D. Toxic multinodular goitre

    Toxic multinodular goitre shows patchy high uptake.

Source note: Original NextPrep sample item — pending expert review. This item is original practice material awaiting independent expert review, so confirm important facts in a standard textbook.

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Questions about this General Medicine question

What is the answer to this General Medicine question?

The best answer is B, Factitious thyrotoxicosis from exogenous thyroid hormone. Low radioiodine uptake with thyrotoxicosis occurs with thyroiditis, exogenous hormone intake and struma ovarii.

Why is "Toxic adenoma" not the answer?

Toxic adenoma shows a hot nodule.

Why is "Graves disease" not the answer?

Graves disease shows diffusely high uptake.

Why is "Toxic multinodular goitre" not the answer?

Toxic multinodular goitre shows patchy high uptake.

What concept does this question test?

It tests Endocrinology: low radioiodine uptake thyrotoxicosis in General Medicine. A low thyroglobulin points to exogenous hormone because the gland is not releasing stored hormone. Graves disease and toxic nodular disease show high or normal uptake.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. The tag is our own editorial judgement, not an official difficulty rating, so read the reason for every option, not only the answer.

How should I study Endocrinology: low radioiodine uptake thyrotoxicosis?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine questions on this site to test what stuck.

Is this a real NEET PG question?

No. It is an original practice item (editorial status: sample, version 1). NextPrep does not publish recalled or leaked questions, and independent faculty review of this item has not been completed yet, so confirm important facts in a standard textbook.