Haematopathology: thrombotic microangiopathy: 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 · Haematopathology: thrombotic microangiopathy

Sample item

A 28-year-old woman has fever, confusion, microangiopathic haemolytic anaemia with schistocytes, severe thrombocytopenia and mild renal impairment. Coagulation tests are normal. What is the underlying defect?

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

The answer and the reasoning

D. Severe deficiency of ADAMTS13, leaving ultra-large von Willebrand multimers

Thrombotic thrombocytopenic purpura is caused by deficiency of the von Willebrand factor-cleaving protease ADAMTS13, usually from autoantibodies. Ultra-large multimers cause platelet microthrombi, leading to haemolysis, thrombocytopenia, neurological signs, fever and renal involvement. Plasma exchange is urgent treatment, and platelet transfusion is avoided.

Option by option

  • A. Activation of coagulation by tissue factor

    Tissue factor activation causes DIC, which has prolonged PT and aPTT and low fibrinogen.

  • B. Deficiency of factor VIII

    Factor VIII deficiency is haemophilia A with a prolonged aPTT.

  • C. Antibodies against platelet glycoprotein IIb/IIIa

    This describes immune thrombocytopenia, which has no haemolysis or schistocytes.

  • D. Severe deficiency of ADAMTS13, leaving ultra-large von Willebrand multimers (correct)

    Correct. Reduced ADAMTS13 causes platelet-rich microthrombi with normal PT and aPTT.

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 D, Severe deficiency of ADAMTS13, leaving ultra-large von Willebrand multimers. Thrombotic thrombocytopenic purpura is caused by deficiency of the von Willebrand factor-cleaving protease ADAMTS13, usually from autoantibodies.

Why is "Activation of coagulation by tissue factor" not the answer?

Tissue factor activation causes DIC, which has prolonged PT and aPTT and low fibrinogen.

Why is "Deficiency of factor VIII" not the answer?

Factor VIII deficiency is haemophilia A with a prolonged aPTT.

Why is "Antibodies against platelet glycoprotein IIb/IIIa" not the answer?

This describes immune thrombocytopenia, which has no haemolysis or schistocytes.

What concept does this question test?

It tests Haematopathology: thrombotic microangiopathy in Pathology. Ultra-large multimers cause platelet microthrombi, leading to haemolysis, thrombocytopenia, neurological signs, fever and renal involvement. Plasma exchange is urgent treatment, and platelet transfusion is avoided.

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 Haematopathology: thrombotic microangiopathy?

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.