Systemic pathology: renal calculus composition: practice question

A Pathology 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.

Try it

Pathology · Systemic pathology: renal calculus composition

Sample item

A 35-year-old woman with recurrent urinary tract infections has a staghorn calculus filling the renal pelvis. Urine pH is alkaline and culture grows Proteus mirabilis. What is the stone composition?

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

The answer and the reasoning

C. Magnesium ammonium phosphate

Urease-producing bacteria split urea into ammonia, which raises urine pH and precipitates magnesium ammonium phosphate (struvite). These stones grow into staghorn shapes and often need surgical removal.

Option by option

  • A. Uric acid

    Uric acid stones form in persistently acidic urine and are radiolucent.

  • B. Cystine

    Cystine stones occur in cystinuria, which is a hereditary transport defect.

  • C. Magnesium ammonium phosphate (correct)

    Correct. Urease-splitting organisms make urine alkaline and form struvite stones.

  • D. Calcium oxalate

    Calcium oxalate stones are most common overall but form in acidic to neutral urine unrelated to infection.

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 Pathology questions

Questions about this Pathology question

What is the answer to this Pathology question?

The best answer is C, Magnesium ammonium phosphate. Urease-producing bacteria split urea into ammonia, which raises urine pH and precipitates magnesium ammonium phosphate (struvite).

Why is "Uric acid" not the answer?

Uric acid stones form in persistently acidic urine and are radiolucent.

Why is "Cystine" not the answer?

Cystine stones occur in cystinuria, which is a hereditary transport defect.

Why is "Calcium oxalate" not the answer?

Calcium oxalate stones are most common overall but form in acidic to neutral urine unrelated to infection.

What concept does this question test?

It tests Systemic pathology: renal calculus composition in Pathology. These stones grow into staghorn shapes and often need surgical removal.

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 Systemic pathology: renal calculus composition?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.