Endocrinology: autoimmune thyroiditis: 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: autoimmune thyroiditis

Sample item

A 38-year-old woman has a firm, painless, diffusely enlarged thyroid, a raised TSH and a low free T4. Biopsy shows dense lymphocytic infiltration with germinal centres and follicular destruction. Which antibody is most characteristically found?

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

The answer and the reasoning

D. Antibodies to thyroid peroxidase

Chronic autoimmune thyroiditis (Hashimoto) is marked by antibodies to thyroid peroxidase and often thyroglobulin, with cell-mediated destruction causing hypothyroidism. Stimulating TSH receptor antibodies cause Graves disease instead.

Option by option

  • A. Antibodies that stimulate the TSH receptor

    These stimulating antibodies cause Graves hyperthyroidism, with a suppressed TSH.

  • B. Antibodies to glutamic acid decarboxylase

    These antibodies are linked to type 1 diabetes and are not the marker of this thyroiditis.

  • C. Antibodies to the muscle acetylcholine receptor

    These antibodies cause myasthenia gravis, which can coexist with thyroid disease but do not cause this thyroiditis.

  • D. Antibodies to thyroid peroxidase (correct)

    Correct. Antibodies to thyroid peroxidase, the enzyme that oxidises iodide, mark Hashimoto thyroiditis.

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 D, Antibodies to thyroid peroxidase. Chronic autoimmune thyroiditis (Hashimoto) is marked by antibodies to thyroid peroxidase and often thyroglobulin, with cell-mediated destruction causing hypothyroidism.

Why is "Antibodies that stimulate the TSH receptor" not the answer?

These stimulating antibodies cause Graves hyperthyroidism, with a suppressed TSH.

Why is "Antibodies to glutamic acid decarboxylase" not the answer?

These antibodies are linked to type 1 diabetes and are not the marker of this thyroiditis.

Why is "Antibodies to the muscle acetylcholine receptor" not the answer?

These antibodies cause myasthenia gravis, which can coexist with thyroid disease but do not cause this thyroiditis.

What concept does this question test?

It tests Endocrinology: autoimmune thyroiditis in Physiology. Stimulating TSH receptor antibodies cause Graves disease instead.

How hard is this question?

We tag it as an application question: it asks you to use a fact on a patient or a finding. 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: autoimmune thyroiditis?

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.