Thyroid: Graves disease: 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 · Thyroid: Graves disease

Sample item

A 32-year-old woman has weight loss, tremor, a diffuse goitre and exophthalmos. Her free T4 is raised and TSH is undetectable. Why does thyroid hormone production continue despite the low TSH?

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

The answer and the reasoning

D. Stimulating autoantibodies act on the TSH receptor and escape negative feedback

In Graves disease, thyroid-stimulating immunoglobulins bind and activate the TSH receptor on follicular cells, causing hormone synthesis and growth of the gland. High thyroid hormone levels suppress TRH and TSH through negative feedback, but the antibodies are not subject to this control. Exophthalmos arises from antibody activity against orbital fibroblasts.

Option by option

  • A. The pituitary secretes TSH in a pulsatile pattern that is missed on testing

    TSH would not be undetectable if it were being secreted in pulses.

  • B. The thyroid gland is stimulated by raised thyrotropin-releasing hormone

    TRH acts through the pituitary and is suppressed by high thyroid hormone.

  • C. Excess iodine overrides the thyroid synthetic pathway

    Iodine excess can cause a transient effect in some people, but it does not explain the immune disease with eye signs.

  • D. Stimulating autoantibodies act on the TSH receptor and escape negative feedback (correct)

    Correct. Receptor-stimulating antibodies drive the gland independently of TSH.

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, Stimulating autoantibodies act on the TSH receptor and escape negative feedback. In Graves disease, thyroid-stimulating immunoglobulins bind and activate the TSH receptor on follicular cells, causing hormone synthesis and growth of the gland.

Why is "The pituitary secretes TSH in a pulsatile pattern that is missed on t…" not the answer?

TSH would not be undetectable if it were being secreted in pulses.

Why is "The thyroid gland is stimulated by raised thyrotropin-releasing hormo…" not the answer?

TRH acts through the pituitary and is suppressed by high thyroid hormone.

Why is "Excess iodine overrides the thyroid synthetic pathway" not the answer?

Iodine excess can cause a transient effect in some people, but it does not explain the immune disease with eye signs.

What concept does this question test?

It tests Thyroid: Graves disease in Physiology. High thyroid hormone levels suppress TRH and TSH through negative feedback, but the antibodies are not subject to this control. Exophthalmos arises from antibody activity against orbital fibroblasts.

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 Thyroid: Graves disease?

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.