Blood and immunity: DIC versus TTP: practice question

A Physiology 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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Physiology · Blood and immunity: DIC versus TTP

Sample item

A septic patient has oozing from venepuncture sites. Laboratory tests show prolonged PT and aPTT, low fibrinogen, raised D-dimer and thrombocytopenia. Which feature separates this from thrombotic thrombocytopenic purpura?

AThrombocytopenia with raised LDHBConsumption of clotting factors prolongs PT and aPTTCMicroangiopathic red cell fragments on the smearDNormal fibrinogen and coagulation times

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

The answer and the reasoning

B. Consumption of clotting factors prolongs PT and aPTT

In DIC widespread thrombin generation consumes platelets and coagulation factors and fibrinogen, so PT, aPTT are prolonged and fibrinogen is low. In TTP platelet-rich microthrombi form from unprocessed vWF multimers and coagulation tests are normal.

Option by option

A. Thrombocytopenia with raised LDH
Thrombocytopenia and raised LDH are common to both disorders.
B. Consumption of clotting factors prolongs PT and aPTT (correct)
Correct. Prolonged PT and aPTT with low fibrinogen mark factor consumption, as in DIC.
C. Microangiopathic red cell fragments on the smear
Schistocytes occur in both DIC and TTP and so do not separate them.
D. Normal fibrinogen and coagulation times
Normal coagulation times and fibrinogen describe TTP, not this patient.

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 Physiology question

What is the answer to this Physiology question?

The best answer is B, Consumption of clotting factors prolongs PT and aPTT. In DIC widespread thrombin generation consumes platelets and coagulation factors and fibrinogen, so PT, aPTT are prolonged and fibrinogen is low.

Why is "Thrombocytopenia with raised LDH" not the answer?

Thrombocytopenia and raised LDH are common to both disorders.

Why is "Microangiopathic red cell fragments on the smear" not the answer?

Schistocytes occur in both DIC and TTP and so do not separate them.

Why is "Normal fibrinogen and coagulation times" not the answer?

Normal coagulation times and fibrinogen describe TTP, not this patient.

What concept does this question test?

It tests Blood and immunity: DIC versus TTP in Physiology. In TTP platelet-rich microthrombi form from unprocessed vWF multimers and coagulation tests are normal.

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 Blood and immunity: DIC versus TTP?

For each system, sketch the key graph (pressure–volume loop, oxygen dissociation curve, nephron handling) and explain it aloud. Then use the flashcards and the other Physiology 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.