Parasitology: cerebral malaria pathogenesis: practice question

A Microbiology 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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Microbiology · Parasitology: cerebral malaria pathogenesis

Sample item

A 5-year-old with Plasmodium falciparum malaria has deep coma, and the peripheral smear shows only ring forms, while trophozoites and schizonts are absent. Which mechanism best explains the cerebral involvement?

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

The answer and the reasoning

A. PfEMP1-mediated cytoadherence of infected red cells to cerebral microvascular endothelium

P. falciparum inserts PfEMP1 into knobs on the red cell membrane. This binds endothelial receptors such as ICAM-1, CD36 and EPCR, so infected cells sequester in the microvasculature and obstruct flow, which is why later stages are absent from the peripheral blood. Cytokines add to the injury.

Option by option

  • A. PfEMP1-mediated cytoadherence of infected red cells to cerebral microvascular endothelium (correct)

    Correct. Sequestration through PfEMP1 explains the absence of mature forms in the blood and the cerebral microvascular obstruction.

  • B. Rupture of hypnozoite-infected hepatocytes

    Hypnozoites occur in vivax and ovale and are not a feature of falciparum malaria.

  • C. Direct invasion of neurons by merozoites

    Merozoites invade red cells, not neurons.

  • D. Blockage of the portal vein by schizonts

    Schizonts are sequestered in capillaries and are not found in a portal obstruction pattern.

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 Microbiology question

What is the answer to this Microbiology question?

The best answer is A, PfEMP1-mediated cytoadherence of infected red cells to cerebral microvascular endothelium. P.

Why is "Rupture of hypnozoite-infected hepatocytes" not the answer?

Hypnozoites occur in vivax and ovale and are not a feature of falciparum malaria.

Why is "Direct invasion of neurons by merozoites" not the answer?

Merozoites invade red cells, not neurons.

Why is "Blockage of the portal vein by schizonts" not the answer?

Schizonts are sequestered in capillaries and are not found in a portal obstruction pattern.

What concept does this question test?

It tests Parasitology: cerebral malaria pathogenesis in Microbiology. falciparum inserts PfEMP1 into knobs on the red cell membrane. This binds endothelial receptors such as ICAM-1, CD36 and EPCR, so infected cells sequester in the microvasculature and obstruct flow, which is why later stages are absent from the peripheral blood. Cytokines add to the injury.

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 Parasitology: cerebral malaria pathogenesis?

Make a one-line identity card for each organism: shape and stain, defining test, toxin, disease and drug. Then use the flashcards and the other Microbiology 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.