Metabolic bone disease: treatment of infantile osteopetrosis: 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: treatment of infantile osteopetrosis

Sample item

An infant with severe autosomal recessive osteopetrosis has anaemia, hepatosplenomegaly and optic nerve compression. Which treatment can correct the underlying defect?

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

The answer and the reasoning

C. Allogeneic haematopoietic stem cell transplantation

Osteoclasts arise from the haematopoietic monocyte-macrophage lineage, so transplanting donor stem cells can restore functioning osteoclasts. It is most effective early, before irreversible neurological damage occurs.

Option by option

  • A. Long-term bisphosphonate therapy

    Bisphosphonates inhibit osteoclasts and would worsen osteopetrosis.

  • B. High-dose calcitriol alone

    Calcitriol is used to stimulate osteoclasts but does not correct the defect in the severe form.

  • C. Allogeneic haematopoietic stem cell transplantation (correct)

    Correct. Donor haematopoietic cells supply normal osteoclasts and correct the primary defect.

  • D. Splenectomy with iron supplements

    Splenectomy and iron do not treat the failure of bone resorption.

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 C, Allogeneic haematopoietic stem cell transplantation. Osteoclasts arise from the haematopoietic monocyte-macrophage lineage, so transplanting donor stem cells can restore functioning osteoclasts.

Why is "Long-term bisphosphonate therapy" not the answer?

Bisphosphonates inhibit osteoclasts and would worsen osteopetrosis.

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

Calcitriol is used to stimulate osteoclasts but does not correct the defect in the severe form.

Why is "Splenectomy with iron supplements" not the answer?

Splenectomy and iron do not treat the failure of bone resorption.

What concept does this question test?

It tests Metabolic bone disease: treatment of infantile osteopetrosis in Orthopaedics. It is most effective early, before irreversible neurological damage occurs.

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: treatment of infantile osteopetrosis?

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.