Metabolic bone disease: medical therapy for X-linked hypophosphataemic rickets: practice question

A Orthopaedics 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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Orthopaedics · Metabolic bone disease: medical therapy for X-linked hypophosphataemic rickets

Sample item

A 3-year-old boy has been diagnosed with X-linked hypophosphataemic rickets. Which conventional medical therapy is used?

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

The answer and the reasoning

B. Oral phosphate with calcitriol

The disease is renal phosphate wasting caused by excess FGF23, so phosphate is replaced orally in divided doses along with active vitamin D to prevent secondary hyperparathyroidism. Burosumab, an anti-FGF23 antibody, is an alternative. Vitamin D alone is ineffective.

Option by option

  • A. Calcium supplements alone

    Calcium alone does not correct the phosphate deficit.

  • B. Oral phosphate with calcitriol (correct)

    Correct. Replacing phosphate with calcitriol is the conventional therapy.

  • C. High-dose cholecalciferol alone

    Cholecalciferol alone does not correct renal phosphate loss.

  • D. Intravenous bisphosphonate

    A bisphosphonate would further reduce bone turnover without addressing the cause.

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 Orthopaedics question

What is the answer to this Orthopaedics question?

The best answer is B, Oral phosphate with calcitriol. The disease is renal phosphate wasting caused by excess FGF23, so phosphate is replaced orally in divided doses along with active vitamin D to prevent secondary hyperparathyroidism.

Why is "Calcium supplements alone" not the answer?

Calcium alone does not correct the phosphate deficit.

Why is "High-dose cholecalciferol alone" not the answer?

Cholecalciferol alone does not correct renal phosphate loss.

Why is "Intravenous bisphosphonate" not the answer?

A bisphosphonate would further reduce bone turnover without addressing the cause.

What concept does this question test?

It tests Metabolic bone disease: medical therapy for X-linked hypophosphataemic rickets in Orthopaedics. Burosumab, an anti-FGF23 antibody, is an alternative. Vitamin D alone is ineffective.

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 Metabolic bone disease: medical therapy for X-linked hypophosphataemic rickets?

Pair each fracture with its classic complication and nerve injured. Then use the flashcards and the other Orthopaedics 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.