Dengue: phases of illness: practice question

A PSM 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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PSM · Dengue: phases of illness

Sample item

An 8-year-old boy is on day 5 of dengue fever. His fever has just subsided, but he is now lethargic with abdominal pain and persistent vomiting. The haematocrit is rising and the platelet count has fallen to 40,000 per microlitre. Which phase of the illness is he entering, and what is the main risk?

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

The answer and the reasoning

D. Critical phase, with plasma leakage that can lead to shock over the next 24 to 48 hours

Plasma leakage in dengue typically begins around defervescence, between days 3 and 7, and defines the critical phase. Warning signs include abdominal pain, persistent vomiting, lethargy and a rising haematocrit with falling platelets. These patients need close monitoring and careful fluid therapy because shock may follow.

Option by option

  • A. Convalescent phase, with the main risk of fluid overload from reabsorption

    Reabsorption of leaked fluid occurs later in convalescence, not when haematocrit is rising.

  • B. Incubation phase, with no risk of complications

    He already has symptoms, so the incubation period has passed.

  • C. Febrile phase, with the main risk of febrile seizures

    The fever has already settled, so this is not the febrile phase.

  • D. Critical phase, with plasma leakage that can lead to shock over the next 24 to 48 hours (correct)

    Defervescence with warning signs and haemoconcentration marks the critical phase with leakage.

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 PSM question

What is the answer to this PSM question?

The best answer is D, Critical phase, with plasma leakage that can lead to shock over the next 24 to 48 hours. Plasma leakage in dengue typically begins around defervescence, between days 3 and 7, and defines the critical phase.

Why is "Convalescent phase, with the main risk of fluid overload from reabsor…" not the answer?

Reabsorption of leaked fluid occurs later in convalescence, not when haematocrit is rising.

Why is "Incubation phase, with no risk of complications" not the answer?

He already has symptoms, so the incubation period has passed.

Why is "Febrile phase, with the main risk of febrile seizures" not the answer?

The fever has already settled, so this is not the febrile phase.

What concept does this question test?

It tests Dengue: phases of illness in PSM. Warning signs include abdominal pain, persistent vomiting, lethargy and a rising haematocrit with falling platelets. These patients need close monitoring and careful fluid therapy because shock may follow.

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 Dengue: phases of illness?

Practise biostatistics with small calculations until sensitivity, predictive values and risk measures are automatic. Then use the flashcards and the other PSM 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.