Neonatology: vitamin K deficiency bleeding: practice question

A Pediatrics 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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Pediatrics · Neonatology: vitamin K deficiency bleeding

Sample item

A 3-week-old exclusively breastfed baby who did not receive vitamin K at birth presents with an intracranial bleed. The platelet count is normal. Which coagulation pattern is expected?

ANormal PT with prolonged aPTTBIsolated prolonged thrombin timeCProlonged PT and aPTT with normal plateletsDProlonged bleeding time with low platelets

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

The answer and the reasoning

C. Prolonged PT and aPTT with normal platelets

Vitamin K is needed to carboxylate factors II, VII, IX and X. In deficiency PT rises first and aPTT follows, while platelets and fibrinogen stay normal. Exclusive breastfeeding provides little vitamin K, which is why prophylaxis is given to every newborn.

Option by option

A. Normal PT with prolonged aPTT
Isolated aPTT prolongation is typical of haemophilia.
B. Isolated prolonged thrombin time
An isolated long thrombin time suggests low fibrinogen or heparin.
C. Prolonged PT and aPTT with normal platelets (correct)
Correct. Deficiency of the vitamin K-dependent factors prolongs PT and aPTT with normal platelets.
D. Prolonged bleeding time with low platelets
Low platelets with a long bleeding time describe thrombocytopenia.

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 Pediatrics question

What is the answer to this Pediatrics question?

The best answer is C, Prolonged PT and aPTT with normal platelets. Vitamin K is needed to carboxylate factors II, VII, IX and X.

Why is "Normal PT with prolonged aPTT" not the answer?

Isolated aPTT prolongation is typical of haemophilia.

Why is "Isolated prolonged thrombin time" not the answer?

An isolated long thrombin time suggests low fibrinogen or heparin.

Why is "Prolonged bleeding time with low platelets" not the answer?

Low platelets with a long bleeding time describe thrombocytopenia.

What concept does this question test?

It tests Neonatology: vitamin K deficiency bleeding in Pediatrics. In deficiency PT rises first and aPTT follows, while platelets and fibrinogen stay normal. Exclusive breastfeeding provides little vitamin K, which is why prophylaxis is given to every newborn.

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 Neonatology: vitamin K deficiency bleeding?

Memorise milestones and the vaccine schedule as tables and revise them often. Then use the flashcards and the other Pediatrics 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.