Haematology: vitamin K deficiency bleeding: 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: vitamin K deficiency bleeding

Sample item

A 5-day-old exclusively breastfed baby born at home, who received no injections, has melaena and oozing from the umbilical stump. Platelet count is normal, and PT is prolonged. Which factors are deficient in their functional form?

AFactors VIII and von Willebrand factorBFactors V and XIIICFactors II, VII, IX and X, because of impaired gamma-carboxylationDFactors XI and XII

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

The answer and the reasoning

C. Factors II, VII, IX and X, because of impaired gamma-carboxylation

Vitamin K is needed for gamma-carboxylation of glutamate residues in factors II, VII, IX and X and in proteins C and S. Newborns have low stores, low gut flora and little vitamin K in breast milk, so they can develop haemorrhagic disease. Prevention is by a single intramuscular dose of vitamin K at birth.

Option by option

A. Factors VIII and von Willebrand factor
Factors VIII and von Willebrand factor are not vitamin K dependent and are deficient in haemophilia A and von Willebrand disease.
B. Factors V and XIII
Factors V and XIII do not depend on vitamin K.
C. Factors II, VII, IX and X, because of impaired gamma-carboxylation (correct)
Correct. Without vitamin K these factors are produced in a non-functional form, prolonging PT and later aPTT.
D. Factors XI and XII
Factors XI and XII do not depend on vitamin K, and factor XII deficiency does not cause bleeding.

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 C, Factors II, VII, IX and X, because of impaired gamma-carboxylation. Vitamin K is needed for gamma-carboxylation of glutamate residues in factors II, VII, IX and X and in proteins C and S.

Why is "Factors VIII and von Willebrand factor" not the answer?

Factors VIII and von Willebrand factor are not vitamin K dependent and are deficient in haemophilia A and von Willebrand disease.

Why is "Factors V and XIII" not the answer?

Factors V and XIII do not depend on vitamin K.

Why is "Factors XI and XII" not the answer?

Factors XI and XII do not depend on vitamin K, and factor XII deficiency does not cause bleeding.

What concept does this question test?

It tests Haematology: vitamin K deficiency bleeding in Pathology. Newborns have low stores, low gut flora and little vitamin K in breast milk, so they can develop haemorrhagic disease. Prevention is by a single intramuscular dose of vitamin K at birth.

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 Haematology: vitamin K deficiency bleeding?

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.