Clinical biochemistry: Paget disease of bone: practice question

A Biochemistry 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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Biochemistry · Clinical biochemistry: Paget disease of bone

Sample item

A 70-year-old has bone pain, an enlarging skull and deafness. Serum alkaline phosphatase is ten times normal, GGT is normal, and calcium and phosphate are normal. What is the likely diagnosis?

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

The answer and the reasoning

B. Paget disease of bone

In Paget disease, markedly raised bone turnover raises bone alkaline phosphatase while calcium and phosphate stay normal. A normal GGT excludes a hepatic source of the alkaline phosphatase. Osteomalacia usually has low calcium or phosphate.

Option by option

  • A. Obstructive jaundice

    Obstructive jaundice would raise the GGT and bilirubin.

  • B. Paget disease of bone (correct)

    Correct. A very high bone alkaline phosphatase with normal calcium and phosphate is the typical profile.

  • C. Osteomalacia

    Osteomalacia usually shows low calcium or phosphate with raised PTH.

  • D. Primary hyperparathyroidism

    Primary hyperparathyroidism has hypercalcaemia and low phosphate.

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 Biochemistry question

What is the answer to this Biochemistry question?

The best answer is B, Paget disease of bone. In Paget disease, markedly raised bone turnover raises bone alkaline phosphatase while calcium and phosphate stay normal.

Why is "Obstructive jaundice" not the answer?

Obstructive jaundice would raise the GGT and bilirubin.

Why is "Osteomalacia" not the answer?

Osteomalacia usually shows low calcium or phosphate with raised PTH.

Why is "Primary hyperparathyroidism" not the answer?

Primary hyperparathyroidism has hypercalcaemia and low phosphate.

What concept does this question test?

It tests Clinical biochemistry: Paget disease of bone in Biochemistry. A normal GGT excludes a hepatic source of the alkaline phosphatase. Osteomalacia usually has low calcium or phosphate.

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 Clinical biochemistry: Paget disease of bone?

Build one table of enzyme deficiency, disease, inheritance and key finding, then revise it by spaced recall. Then use the flashcards and the other Biochemistry 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.