Endocrinology: osteomalacia: practice question

A General Medicine 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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General Medicine · Endocrinology: osteomalacia

Sample item

A 30-year-old woman who is strictly veiled and eats little dairy has diffuse bone pain, proximal muscle weakness and a waddling gait. Radiographs show bilateral pseudofractures (Looser zones). Which biochemical pattern is expected?

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

The answer and the reasoning

B. Low-normal calcium, low phosphate, raised alkaline phosphatase and raised PTH

Vitamin D deficiency lowers calcium absorption, leading to secondary hyperparathyroidism, which raises PTH, lowers phosphate through renal wasting and increases alkaline phosphatase. This defective mineralisation of osteoid causes osteomalacia, and Looser zones are characteristic. Treatment is vitamin D and calcium replacement.

Option by option

  • A. High calcium, low phosphate, raised alkaline phosphatase and raised PTH

    A high calcium with raised PTH suggests primary hyperparathyroidism.

  • B. Low-normal calcium, low phosphate, raised alkaline phosphatase and raised PTH (correct)

    Secondary hyperparathyroidism with low phosphate and raised ALP is the typical osteomalacia pattern.

  • C. Normal calcium and phosphate, markedly raised alkaline phosphatase and normal PTH

    Isolated high ALP with normal calcium, phosphate and PTH characterises Paget disease of bone.

  • D. Normal calcium, phosphate, alkaline phosphatase and PTH

    Normal biochemistry is typical of osteoporosis, in which there is no defect in mineralisation.

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 General Medicine question

What is the answer to this General Medicine question?

The best answer is B, Low-normal calcium, low phosphate, raised alkaline phosphatase and raised PTH. Vitamin D deficiency lowers calcium absorption, leading to secondary hyperparathyroidism, which raises PTH, lowers phosphate through renal wasting and increases alkaline phosphatase.

Why is "High calcium, low phosphate, raised alkaline phosphatase and raised P…" not the answer?

A high calcium with raised PTH suggests primary hyperparathyroidism.

Why is "Normal calcium and phosphate, markedly raised alkaline phosphatase an…" not the answer?

Isolated high ALP with normal calcium, phosphate and PTH characterises Paget disease of bone.

Why is "Normal calcium, phosphate, alkaline phosphatase and PTH" not the answer?

Normal biochemistry is typical of osteoporosis, in which there is no defect in mineralisation.

What concept does this question test?

It tests Endocrinology: osteomalacia in General Medicine. This defective mineralisation of osteoid causes osteomalacia, and Looser zones are characteristic. Treatment is vitamin D and calcium replacement.

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 Endocrinology: osteomalacia?

For each disease know the classic presentation, the best test, and the first-line treatment. Then use the flashcards and the other General Medicine 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.