Haematology: haemolytic uraemic 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 · Haematology: haemolytic uraemic syndrome

Sample item

A 4-year-old child had bloody diarrhoea 5 days ago and now has pallor and oliguria. Haemoglobin is 7 g/dL, platelets 40,000 per microlitre, creatinine is raised, schistocytes are present, and PT and aPTT are normal. Which mechanism underlies this illness?

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

The answer and the reasoning

A. Shiga toxin-mediated injury to glomerular endothelium with microthrombi

Typical haemolytic uraemic syndrome follows infection with Shiga toxin-producing Escherichia coli such as O157:H7. The toxin binds Gb3 receptors on renal endothelium, causing thrombotic microangiopathy with haemolysis, thrombocytopenia and acute kidney injury. Coagulation tests are normal, and antibiotics are avoided because they may increase toxin release.

Option by option

  • A. Shiga toxin-mediated injury to glomerular endothelium with microthrombi (correct)

    Shiga toxin damages endothelium to produce the triad after a diarrhoeal illness.

  • B. Severe deficiency of ADAMTS13 leaving ultra-large von Willebrand multimers

    ADAMTS13 deficiency causes TTP, which classically has prominent neurological features and usually milder renal involvement.

  • C. Widespread tissue factor release consuming clotting factors

    Consumption of clotting factors in DIC prolongs PT and aPTT, which are normal here.

  • D. Antibodies to platelet factor 4-heparin complexes

    Anti-PF4-heparin antibodies cause heparin-induced thrombocytopenia and require heparin exposure.

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, Shiga toxin-mediated injury to glomerular endothelium with microthrombi. Typical haemolytic uraemic syndrome follows infection with Shiga toxin-producing Escherichia coli such as O157:H7.

Why is "Severe deficiency of ADAMTS13 leaving ultra-large von Willebrand mult…" not the answer?

ADAMTS13 deficiency causes TTP, which classically has prominent neurological features and usually milder renal involvement.

Why is "Widespread tissue factor release consuming clotting factors" not the answer?

Consumption of clotting factors in DIC prolongs PT and aPTT, which are normal here.

Why is "Antibodies to platelet factor 4-heparin complexes" not the answer?

Anti-PF4-heparin antibodies cause heparin-induced thrombocytopenia and require heparin exposure.

What concept does this question test?

It tests Haematology: haemolytic uraemic syndrome in Pathology. The toxin binds Gb3 receptors on renal endothelium, causing thrombotic microangiopathy with haemolysis, thrombocytopenia and acute kidney injury. Coagulation tests are normal, and antibiotics are avoided because they may increase toxin release.

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 Haematology: haemolytic uraemic 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.