Question

Anti-thrombin III levels in disseminated intravascular coagulation

• A. Are decreased
• B. Are increased
• C. Remain the same
• D. Are variable

Hint:

Think about what happens to any clotting inhibitor when clotting runs out of control everywhere.

Answer 1

The Correct Option is A

Disseminated intravascular coagulation (DIC) is a state where clotting is switched on throughout the small blood vessels, and this question asks what happens to antithrombin III, the body's natural anticlotting protein, during that process.

1. Decreased: Antithrombin III gets used up as it tries to block the flood of thrombin being formed everywhere in DIC, so its blood level drops. This matches the consumption pattern seen with platelets and fibrinogen in DIC.
2. Increased: There is no mechanism in DIC that would raise antithrombin III; the process only consumes clotting factors and their inhibitors.
3. Remain the same: This ignores the ongoing consumption that defines DIC, so the level cannot stay unchanged.
4. Variable: This is too vague. The change is consistently in one direction, downward, not unpredictable.

Since antithrombin III is being consumed alongside other clotting factors as the body tries to control widespread clotting, its level falls in DIC, just like fibrinogen and platelet counts do.

Let's summarize:

• DIC causes consumption of clotting factors, platelets, and their natural inhibitors together.
• A falling antithrombin III level supports the diagnosis of DIC.

So the correct answer is that antithrombin III levels are decreased in disseminated intravascular coagulation.