Nephrology: practice question

A Pediatrics 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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Pediatrics · Nephrology

Sample item

A 7-year-old has cola-coloured urine, periorbital oedema and hypertension two weeks after a sore throat. Which serological finding is expected?

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

The answer and the reasoning

A. Low serum C3 with normal C4

This is post-streptococcal glomerulonephritis, an immune-complex disease that activates the alternative complement pathway. C3 is low in the acute phase and returns to normal in about two months. Persistently low C3 suggests another cause.

Option by option

  • A. Low serum C3 with normal C4 (correct)

    Correct. Alternative pathway consumption lowers C3 while C4 stays normal.

  • B. Positive anti-double-stranded DNA

    Anti-dsDNA is a feature of lupus, which is unlikely after a streptococcal infection.

  • C. Raised C3

    C3 is reduced, not raised, in the acute disease.

  • D. Low C3 and low C4

    Low C4 as well suggests classical pathway activation, as in lupus nephritis.

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 Pediatrics question

What is the answer to this Pediatrics question?

The best answer is A, Low serum C3 with normal C4. This is post-streptococcal glomerulonephritis, an immune-complex disease that activates the alternative complement pathway.

Why is "Positive anti-double-stranded DNA" not the answer?

Anti-dsDNA is a feature of lupus, which is unlikely after a streptococcal infection.

Why is "Raised C3" not the answer?

C3 is reduced, not raised, in the acute disease.

Why is "Low C3 and low C4" not the answer?

Low C4 as well suggests classical pathway activation, as in lupus nephritis.

What concept does this question test?

It tests Nephrology in Pediatrics. C3 is low in the acute phase and returns to normal in about two months. Persistently low C3 suggests another cause.

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 Nephrology?

Memorise milestones and the vaccine schedule as tables and revise them often. Then use the flashcards and the other Pediatrics 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.