Injuries and wounds: beta-APP in diffuse axonal injury: practice question

A Forensic 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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Forensic Medicine · Injuries and wounds: beta-APP in diffuse axonal injury

Sample item

A pedestrian struck by a car remains deeply unconscious and dies about 8 hours later. Routine haematoxylin and eosin sections of the brain show no definite lesion. Which technique can best demonstrate axonal injury at this survival time?

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

The answer and the reasoning

A. Beta-APP immunohistochemistry

Damaged axons stop transporting beta-amyloid precursor protein, which accumulates and can be detected by immunohistochemistry after a survival of only a few hours, long before changes appear on routine stains. This makes it the preferred test for diffuse axonal injury in early deaths. Haemosiderin staining needs days.

Option by option

  • A. Beta-APP immunohistochemistry (correct)

    Correct. Beta-APP accumulates in injured axons within hours.

  • B. Oil red O stain on frozen sections

    Oil red O shows neutral fat and is not a marker of axonal injury.

  • C. Luxol fast blue stain

    Luxol fast blue stains myelin and does not mark early axonal injury.

  • D. Perls' Prussian blue stain

    Prussian blue demonstrates haemosiderin, which takes days to form.

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 Forensic Medicine question

What is the answer to this Forensic Medicine question?

The best answer is A, Beta-APP immunohistochemistry. Damaged axons stop transporting beta-amyloid precursor protein, which accumulates and can be detected by immunohistochemistry after a survival of only a few hours, long before changes appear on routine stains.

Why is "Oil red O stain on frozen sections" not the answer?

Oil red O shows neutral fat and is not a marker of axonal injury.

Why is "Luxol fast blue stain" not the answer?

Luxol fast blue stains myelin and does not mark early axonal injury.

Why is "Perls' Prussian blue stain" not the answer?

Prussian blue demonstrates haemosiderin, which takes days to form.

What concept does this question test?

It tests Injuries and wounds: beta-APP in diffuse axonal injury in Forensic Medicine. This makes it the preferred test for diffuse axonal injury in early deaths. Haemosiderin staining needs days.

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 Injuries and wounds: beta-APP in diffuse axonal injury?

Learn postmortem changes with their timelines, and toxicology as poison, sign, test and antidote. Then use the flashcards and the other Forensic 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.