Surgical infections: gas gangrene: 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 · Surgical infections: gas gangrene

Sample item

A man with a crush injury develops severe pain, a foul-smelling brown discharge, crepitus and rapidly spreading muscle necrosis. Which organism and toxin are responsible?

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

The answer and the reasoning

A. Clostridium perfringens with alpha toxin (lecithinase)

Clostridial myonecrosis is caused by C. perfringens, whose alpha toxin (a lecithinase) destroys cell membranes and causes gas formation and necrosis. Treatment is urgent radical debridement, high-dose penicillin with clindamycin, and supportive care, with hyperbaric oxygen as an adjunct. Delay in surgery is fatal.

Option by option

  • A. Clostridium perfringens with alpha toxin (lecithinase) (correct)

    Correct. Alpha toxin of C. perfringens causes myonecrosis.

  • B. Pseudomonas with exotoxin A

    Exotoxin A is a Pseudomonas toxin not typical here.

  • C. Streptococcus pyogenes with streptolysin only

    Streptococcal toxins cause necrotising infection without this pattern of gas in muscle.

  • D. Staphylococcus aureus with TSST-1

    TSST-1 causes toxic shock syndrome.

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.

More General Surgery questions

Questions about this General Surgery question

What is the answer to this General Surgery question?

The best answer is A, Clostridium perfringens with alpha toxin (lecithinase). Clostridial myonecrosis is caused by C.

Why is "Pseudomonas with exotoxin A" not the answer?

Exotoxin A is a Pseudomonas toxin not typical here.

Why is "Streptococcus pyogenes with streptolysin only" not the answer?

Streptococcal toxins cause necrotising infection without this pattern of gas in muscle.

Why is "Staphylococcus aureus with TSST-1" not the answer?

TSST-1 causes toxic shock syndrome.

What concept does this question test?

It tests Surgical infections: gas gangrene in General Surgery. perfringens, whose alpha toxin (a lecithinase) destroys cell membranes and causes gas formation and necrosis. Treatment is urgent radical debridement, high-dose penicillin with clindamycin, and supportive care, with hyperbaric oxygen as an adjunct. Delay in surgery is fatal.

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 Surgical infections: gas gangrene?

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.