Nephrology and electrolytes: medullary sponge kidney: practice question

A General Medicine 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 Medicine · Nephrology and electrolytes: medullary sponge kidney

Sample item

A 35-year-old man has recurrent calcium stones and episodes of haematuria with normal renal function. An intravenous urogram shows brush-like linear streaks of contrast in the papillae with small cystic dilatations of the collecting ducts. What is the diagnosis?

AAutosomal dominant polycystic kidney diseaseBMedullary sponge kidneyCRenal tuberculosisDAnalgesic nephropathy with papillary necrosis

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

The answer and the reasoning

B. Medullary sponge kidney

Medullary sponge kidney involves cystic dilatation of the collecting ducts in the renal pyramids, with a brush-like appearance after contrast. It is associated with hypercalciuria, calcium stones, nephrocalcinosis and recurrent infection, but renal function is usually preserved.

Option by option

A. Autosomal dominant polycystic kidney disease
ADPKD shows enlarged kidneys with multiple large cysts in both cortex and medulla and progresses to renal failure.
B. Medullary sponge kidney (correct)
Correct. The brush-like papillary pattern with calcium stones is characteristic.
C. Renal tuberculosis
Renal tuberculosis shows calyceal erosion, strictures and calcification, with sterile pyuria.
D. Analgesic nephropathy with papillary necrosis
Papillary necrosis shows sloughed papillae with a ring or club-shaped calyceal deformity after prolonged analgesic use.

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.

Questions about this General Medicine question

What is the answer to this General Medicine question?

The best answer is B, Medullary sponge kidney. Medullary sponge kidney involves cystic dilatation of the collecting ducts in the renal pyramids, with a brush-like appearance after contrast.

Why is "Autosomal dominant polycystic kidney disease" not the answer?

ADPKD shows enlarged kidneys with multiple large cysts in both cortex and medulla and progresses to renal failure.

Why is "Renal tuberculosis" not the answer?

Renal tuberculosis shows calyceal erosion, strictures and calcification, with sterile pyuria.

Why is "Analgesic nephropathy with papillary necrosis" not the answer?

Papillary necrosis shows sloughed papillae with a ring or club-shaped calyceal deformity after prolonged analgesic use.

What concept does this question test?

It tests Nephrology and electrolytes: medullary sponge kidney in General Medicine. It is associated with hypercalciuria, calcium stones, nephrocalcinosis and recurrent infection, but renal function is usually preserved.

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 and electrolytes: medullary sponge kidney?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine 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.