Ear and audiology: osteopetrosis: practice question

A ENT 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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ENT · Ear and audiology: osteopetrosis

Sample item

A 2-year-old has anaemia, hepatosplenomegaly, visual loss, facial palsy and conductive deafness. X-rays show uniformly dense bones. What is the basic defect?

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

The answer and the reasoning

A. Failure of osteoclast resorption causing narrowing of skull foramina

In osteopetrosis, osteoclasts fail to resorb bone, so bone is dense and brittle and marrow space is lost, giving anaemia and extramedullary haematopoiesis. Narrowed optic, facial canal and ossicular spaces cause blindness, facial palsy and deafness.

Option by option

  • A. Failure of osteoclast resorption causing narrowing of skull foramina (correct)

    Correct. Failed osteoclast resorption leaves dense bone and narrowed foramina and canals.

  • B. Excessive osteoclast activity with disordered remodelling

    Excessive osteoclast activity with chaotic remodelling is the process in Paget disease.

  • C. Unmineralised osteoid from vitamin D deficiency

    Unmineralised osteoid from vitamin D deficiency produces rickets, with soft bones rather than dense ones.

  • D. Defective synthesis of type I collagen

    Defective type I collagen is the defect in osteogenesis imperfecta, with fragile bones and blue sclerae.

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 ENT question

What is the answer to this ENT question?

The best answer is A, Failure of osteoclast resorption causing narrowing of skull foramina. In osteopetrosis, osteoclasts fail to resorb bone, so bone is dense and brittle and marrow space is lost, giving anaemia and extramedullary haematopoiesis.

Why is "Excessive osteoclast activity with disordered remodelling" not the answer?

Excessive osteoclast activity with chaotic remodelling is the process in Paget disease.

Why is "Unmineralised osteoid from vitamin D deficiency" not the answer?

Unmineralised osteoid from vitamin D deficiency produces rickets, with soft bones rather than dense ones.

Why is "Defective synthesis of type I collagen" not the answer?

Defective type I collagen is the defect in osteogenesis imperfecta, with fragile bones and blue sclerae.

What concept does this question test?

It tests Ear and audiology: osteopetrosis in ENT. Narrowed optic, facial canal and ossicular spaces cause blindness, facial palsy and deafness.

How hard is this question?

We tag it as a multi-step question: it asks you to combine more than one idea. 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 Ear and audiology: osteopetrosis?

Learn tuning fork results and audiogram patterns by sketching them. Then use the flashcards and the other ENT 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.