Disseminated intravasal coagulation

1. Big picture

Disseminated intravascular coagulation (DIC) is not a primary disease. It is a severe acquired coagulation syndrome caused by another serious condition, classically sepsis, acute promyelocytic leukemia (APL), trauma, obstetric complications, malignancy, or massive hemolysis/transfusion reaction.

The examiner wants you to say:

DIC = systemic activation of coagulation → diffuse microthrombi → consumption of platelets and clotting factors → bleeding + organ dysfunction.

So DIC is paradoxical: the patient may clot and bleed at the same time.

Core pattern:

Trigger disease
↓
Systemic tissue factor / inflammatory activation
↓
Thrombin generation + fibrin microthrombi
↓
Platelet and factor consumption
↓
Bleeding + ischemic organ damage + ↑ D-dimer

The hematology textbook defines DIC as uncontrolled intravascular activation of coagulation causing microvascular thrombi, diffuse fibrin formation, endothelial damage, organ dysfunction, consumption of platelets/coagulation factors, and hemorrhagic complications due to fibrinolysis. It emphasizes that DIC is not independent and that the underlying trigger must always be sought.

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