Neoplasia: tumour lysis syndrome: practice question

A Pathology 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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Pathology · Neoplasia: tumour lysis syndrome

Sample item

Twelve hours after the first cycle of chemotherapy for Burkitt lymphoma, a boy develops oliguria, tetany and arrhythmia. Which set of laboratory findings is expected?

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

The answer and the reasoning

A. High potassium, phosphate and uric acid with low calcium

Rapid lysis of tumour cells releases potassium, phosphate and nucleic acids (metabolised to uric acid). Phosphate binds calcium, producing hypocalcaemia and tetany. Uric acid and calcium phosphate crystals injure the kidney, so prophylaxis uses hydration and allopurinol or rasburicase.

Option by option

  • A. High potassium, phosphate and uric acid with low calcium (correct)

    Correct. Release of intracellular contents raises K, phosphate and urate and lowers calcium.

  • B. Low potassium, phosphate and uric acid with high calcium

    Cell lysis raises, not lowers, potassium, phosphate and uric acid.

  • C. High sodium and glucose with low phosphate

    Sodium and glucose are not the characteristic changes of cell lysis.

  • D. High potassium and uric acid with high calcium

    Calcium falls rather than rises because phosphate binds it.

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 Pathology question

What is the answer to this Pathology question?

The best answer is A, High potassium, phosphate and uric acid with low calcium. Rapid lysis of tumour cells releases potassium, phosphate and nucleic acids (metabolised to uric acid).

Why is "Low potassium, phosphate and uric acid with high calcium" not the answer?

Cell lysis raises, not lowers, potassium, phosphate and uric acid.

Why is "High sodium and glucose with low phosphate" not the answer?

Sodium and glucose are not the characteristic changes of cell lysis.

Why is "High potassium and uric acid with high calcium" not the answer?

Calcium falls rather than rises because phosphate binds it.

What concept does this question test?

It tests Neoplasia: tumour lysis syndrome in Pathology. Phosphate binds calcium, producing hypocalcaemia and tetany. Uric acid and calcium phosphate crystals injure the kidney, so prophylaxis uses hydration and allopurinol or rasburicase.

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 Neoplasia: tumour lysis syndrome?

Learn each disease as a bundle: cause, key histology, markers, and the clinical hallmark. Then use the flashcards and the other Pathology 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.