Metabolic bone: pseudohypoparathyroidism: 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: pseudohypoparathyroidism

Sample item

A 12-year-old with a round face, short stature and short fourth and fifth metacarpals has low calcium, high phosphate and a raised parathyroid hormone. What is the diagnosis?

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

The answer and the reasoning

D. Pseudohypoparathyroidism (Albright hereditary osteodystrophy)

In pseudohypoparathyroidism the tissues are resistant to parathyroid hormone, so calcium is low, phosphate is high and PTH is raised. Albright hereditary osteodystrophy comprises a round face, short stature, obesity and brachydactyly with short fourth and fifth metacarpals. Treatment is with calcium and active vitamin D.

Option by option

  • A. Hypothyroidism

    Hypothyroidism does not cause hypocalcaemia with high PTH.

  • B. Vitamin D deficiency rickets

    Vitamin D deficiency rickets gives low phosphate and does not cause brachydactyly.

  • C. Primary hyperparathyroidism

    Primary hyperparathyroidism causes high calcium and low phosphate.

  • D. Pseudohypoparathyroidism (Albright hereditary osteodystrophy) (correct)

    Correct. Hypocalcaemia with high PTH and short fourth and fifth metacarpals indicates pseudohypoparathyroidism.

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 D, Pseudohypoparathyroidism (Albright hereditary osteodystrophy). In pseudohypoparathyroidism the tissues are resistant to parathyroid hormone, so calcium is low, phosphate is high and PTH is raised.

Why is "Hypothyroidism" not the answer?

Hypothyroidism does not cause hypocalcaemia with high PTH.

Why is "Vitamin D deficiency rickets" not the answer?

Vitamin D deficiency rickets gives low phosphate and does not cause brachydactyly.

Why is "Primary hyperparathyroidism" not the answer?

Primary hyperparathyroidism causes high calcium and low phosphate.

What concept does this question test?

It tests Metabolic bone: pseudohypoparathyroidism in Orthopaedics. Albright hereditary osteodystrophy comprises a round face, short stature, obesity and brachydactyly with short fourth and fifth metacarpals. Treatment is with calcium and active vitamin D.

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 Metabolic bone: pseudohypoparathyroidism?

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.