Haematology: acquired haemophilia: 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: acquired haemophilia

Sample item

A 60-year-old man with no previous bleeding history develops large spontaneous muscle haematomas. Platelets and PT are normal and aPTT is 78 seconds. When mixed 1:1 with normal plasma, the aPTT corrects partly and then lengthens again after 2 hours of incubation at 37 degrees Celsius. What is the diagnosis?

AAcquired factor VIII inhibitorBCongenital haemophilia ACVitamin K deficiencyDType 1 von Willebrand disease

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

The answer and the reasoning

A. Acquired factor VIII inhibitor

Failure of an isolated prolonged aPTT to stay corrected after mixing, particularly after incubation, indicates a time-dependent inhibitor, most often an autoantibody to factor VIII. Acquired haemophilia A presents with severe bleeding in older adults or postpartum and in autoimmune disease or malignancy. Simple factor deficiencies correct on mixing.

Option by option

A. Acquired factor VIII inhibitor (correct)
A late-onset bleed with an uncorrected mixing study fits an acquired factor VIII inhibitor.
B. Congenital haemophilia A
Congenital haemophilia presents in childhood, and its aPTT corrects on mixing.
C. Vitamin K deficiency
Vitamin K deficiency prolongs PT as well, and both correct on mixing.
D. Type 1 von Willebrand disease
Von Willebrand disease causes mucosal bleeding and a mildly prolonged aPTT that corrects on mixing.

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 Pathology question

What is the answer to this Pathology question?

The best answer is A, Acquired factor VIII inhibitor. Failure of an isolated prolonged aPTT to stay corrected after mixing, particularly after incubation, indicates a time-dependent inhibitor, most often an autoantibody to factor VIII.

Why is "Congenital haemophilia A" not the answer?

Congenital haemophilia presents in childhood, and its aPTT corrects on mixing.

Why is "Vitamin K deficiency" not the answer?

Vitamin K deficiency prolongs PT as well, and both correct on mixing.

Why is "Type 1 von Willebrand disease" not the answer?

Von Willebrand disease causes mucosal bleeding and a mildly prolonged aPTT that corrects on mixing.

What concept does this question test?

It tests Haematology: acquired haemophilia in Pathology. Acquired haemophilia A presents with severe bleeding in older adults or postpartum and in autoimmune disease or malignancy. Simple factor deficiencies correct on mixing.

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: acquired haemophilia?

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.