Endocrinology: factitious thyrotoxicosis: practice question

A Physiology 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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Physiology · Endocrinology: factitious thyrotoxicosis

Sample item

A 35-year-old nurse has palpitations, weight loss and tremor. TSH is suppressed and free T4 raised. The thyroid is not palpable, radioiodine uptake is very low and serum thyroglobulin is low. What is the most likely diagnosis?

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

The answer and the reasoning

C. Exogenous thyroxine ingestion

Exogenous hormone suppresses TSH, so the gland is quiet, with low uptake and low thyroglobulin. In Graves disease and toxic nodules uptake is high, and thyroglobulin is raised in thyroiditis.

Option by option

  • A. TSH-secreting adenoma

    A TSH-secreting adenoma raises TSH rather than suppressing it.

  • B. Toxic multinodular goitre

    Toxic nodular disease shows focal high uptake.

  • C. Exogenous thyroxine ingestion (correct)

    Correct. Low uptake and low thyroglobulin with raised T4 indicate an extrinsic source.

  • D. Graves disease

    Graves disease shows diffusely high radioiodine 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 Physiology question

What is the answer to this Physiology question?

The best answer is C, Exogenous thyroxine ingestion. Exogenous hormone suppresses TSH, so the gland is quiet, with low uptake and low thyroglobulin.

Why is "TSH-secreting adenoma" not the answer?

A TSH-secreting adenoma raises TSH rather than suppressing it.

Why is "Toxic multinodular goitre" not the answer?

Toxic nodular disease shows focal high uptake.

Why is "Graves disease" not the answer?

Graves disease shows diffusely high radioiodine uptake.

What concept does this question test?

It tests Endocrinology: factitious thyrotoxicosis in Physiology. In Graves disease and toxic nodules uptake is high, and thyroglobulin is raised in thyroiditis.

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: factitious thyrotoxicosis?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.