Endocrine drugs: vitamin D toxicity: practice question

A Pharmacology 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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Pharmacology · Endocrine drugs: vitamin D toxicity

Sample item

A child given very large doses of cholecalciferol for rickets develops vomiting, polyuria and constipation with a serum calcium of 3.4 mmol/L. What is the diagnosis?

ANephrogenic diabetes insipidus from lithiumBHypoparathyroidismCVitamin D deficiencyDHypervitaminosis D with hypercalcaemia

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

The answer and the reasoning

D. Hypervitaminosis D with hypercalcaemia

Excess vitamin D increases gut calcium absorption and bone resorption, causing hypercalcaemia with polyuria, constipation, vomiting and nephrocalcinosis. Calcitriol is the active form and cholecalciferol and ergocalciferol are precursors needing hydroxylation.

Option by option

A. Nephrogenic diabetes insipidus from lithium
No lithium exposure is given.
B. Hypoparathyroidism
Hypoparathyroidism causes hypocalcaemia.
C. Vitamin D deficiency
Deficiency causes low calcium.
D. Hypervitaminosis D with hypercalcaemia (correct)
Correct. Excessive vitamin D causes hypercalcaemia.

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.

Questions about this Pharmacology question

What is the answer to this Pharmacology question?

The best answer is D, Hypervitaminosis D with hypercalcaemia. Excess vitamin D increases gut calcium absorption and bone resorption, causing hypercalcaemia with polyuria, constipation, vomiting and nephrocalcinosis.

Why is "Nephrogenic diabetes insipidus from lithium" not the answer?

No lithium exposure is given.

Why is "Hypoparathyroidism" not the answer?

Hypoparathyroidism causes hypocalcaemia.

Why is "Vitamin D deficiency" not the answer?

Deficiency causes low calcium.

What concept does this question test?

It tests Endocrine drugs: vitamin D toxicity in Pharmacology. Calcitriol is the active form and cholecalciferol and ergocalciferol are precursors needing hydroxylation.

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 Endocrine drugs: vitamin D toxicity?

Learn drugs as classes, then the exception in each class that an examiner would pick. Then use the flashcards and the other Pharmacology 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.