Trauma and burns: traumatic asphyxia: practice question

A General Surgery 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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General Surgery · Trauma and burns: traumatic asphyxia

Sample item

A worker is crushed between a lorry and a wall. He has deep blue-purple discolouration and petechiae of the face and neck, bilateral subconjunctival haemorrhages, and a sharp line of demarcation at the upper chest. What is the mechanism?

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

The answer and the reasoning

A. Sudden rise in intrathoracic pressure transmitted retrogradely to the valveless veins of the head and neck

In traumatic asphyxia, compression of the chest against a closed glottis raises thoracic pressure and forces blood back through the valveless veins of the head and neck, producing cyanosis, petechiae and subconjunctival haemorrhage above the level of compression. Associated thoracic injuries often determine the outcome.

Option by option

  • A. Sudden rise in intrathoracic pressure transmitted retrogradely to the valveless veins of the head and neck (correct)

    Correct. Retrograde venous pressure transmission produces a cyanotic, petechial face and neck.

  • B. Cervical spine injury causing sympathetic paralysis

    Sympathetic paralysis causes flushing, hypotension and bradycardia without petechiae.

  • C. Carbon monoxide poisoning

    Carbon monoxide poisoning produces a cherry-red colour, not discrete purple petechiae with a sharp demarcation.

  • D. Fat embolism from long bone fractures

    Fat embolism produces petechiae on the chest and axillae, with respiratory and cerebral signs, after a delay.

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 General Surgery question

What is the answer to this General Surgery question?

The best answer is A, Sudden rise in intrathoracic pressure transmitted retrogradely to the valveless veins of the head and neck. In traumatic asphyxia, compression of the chest against a closed glottis raises thoracic pressure and forces blood back through the valveless veins of the head and neck, producing cyanosis, petechiae and subconjunctival haemorrhage above the level of compression.

Why is "Cervical spine injury causing sympathetic paralysis" not the answer?

Sympathetic paralysis causes flushing, hypotension and bradycardia without petechiae.

Why is "Carbon monoxide poisoning" not the answer?

Carbon monoxide poisoning produces a cherry-red colour, not discrete purple petechiae with a sharp demarcation.

Why is "Fat embolism from long bone fractures" not the answer?

Fat embolism produces petechiae on the chest and axillae, with respiratory and cerebral signs, after a delay.

What concept does this question test?

It tests Trauma and burns: traumatic asphyxia in General Surgery. Associated thoracic injuries often determine the outcome.

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 Trauma and burns: traumatic asphyxia?

Learn classic signs and eponyms alongside what they diagnose. Then use the flashcards and the other General Surgery 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.