General physiology: heat stroke versus fever: 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 · General physiology: heat stroke versus fever

Sample item

A 72-year-old man living alone is found confused during a heat wave. His core temperature is 41.2 degrees C, his skin is hot and dry, and antipyretics do not lower the temperature. Which mechanism best explains the hyperthermia?

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

The answer and the reasoning

D. Failed heat loss, with sweating lost, so temperature rises without a set-point change

In heat stroke the heat-loss mechanisms are overwhelmed or fail, sweating stops and core temperature climbs although the hypothalamic set point is unchanged. Because prostaglandin E2 is not involved, antipyretics are ineffective, unlike in fever. Heat exhaustion causes circulatory collapse with a near-normal temperature.

Option by option

  • A. Excess thyroid hormone uncoupling oxidative phosphorylation in skeletal muscle

    Thyrotoxic hypermetabolism raises temperature chronically and does not explain a heat-wave presentation with dry skin.

  • B. Salt and water depletion from heavy sweating, causing collapse with near-normal temperature

    This describes heat exhaustion, in which temperature stays near normal and mentation is preserved.

  • C. A raised hypothalamic set point driven by interleukin-1 and prostaglandin E2 release

    A raised set point describes fever, which responds to antipyretics and is not accompanied by failed sweating.

  • D. Failed heat loss, with sweating lost, so temperature rises without a set-point change (correct)

    Correct. Heat loss fails and the set point is unchanged, so antipyretics do not work.

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, Failed heat loss, with sweating lost, so temperature rises without a set-point change. In heat stroke the heat-loss mechanisms are overwhelmed or fail, sweating stops and core temperature climbs although the hypothalamic set point is unchanged.

Why is "Excess thyroid hormone uncoupling oxidative phosphorylation in skelet…" not the answer?

Thyrotoxic hypermetabolism raises temperature chronically and does not explain a heat-wave presentation with dry skin.

Why is "Salt and water depletion from heavy sweating, causing collapse with n…" not the answer?

This describes heat exhaustion, in which temperature stays near normal and mentation is preserved.

Why is "A raised hypothalamic set point driven by interleukin-1 and prostagla…" not the answer?

A raised set point describes fever, which responds to antipyretics and is not accompanied by failed sweating.

What concept does this question test?

It tests General physiology: heat stroke versus fever in Physiology. Because prostaglandin E2 is not involved, antipyretics are ineffective, unlike in fever. Heat exhaustion causes circulatory collapse with a near-normal temperature.

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 General physiology: heat stroke versus fever?

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.