DIC (Disseminated Intravascular Coagulation)

Disseminated intravascular coagulation (DIC) is an acquired syndrome characterized by widespread, systemic activation of coagulation, leading to intravascular fibrin formation, microvascular thrombosis, and consumption of platelets and clotting factors. This consumption then results in a paradoxical bleeding tendency. DIC is always secondary to an underlying condition and is itself a sign of severe systemic illness.

Common triggers include sepsis (the most common cause), severe trauma, obstetric complications (placental abruption, amniotic fluid embolism, retained dead fetus), malignancies (especially acute promyelocytic leukemia, mucinous adenocarcinomas), and severe transfusion reactions. The pathogenesis involves tissue factor exposure, cytokine release, endothelial damage, and impaired natural anticoagulant systems (protein C, antithrombin).

DIC manifests clinically with bleeding (oozing from puncture sites, mucosal bleeding, hematuria), thrombosis (acral cyanosis, organ infarction), and end-organ dysfunction (acute kidney injury, ARDS, hepatic dysfunction, neurologic changes). Diagnosis is based on a combination of clinical context plus laboratory abnormalities — thrombocytopenia, prolonged PT/aPTT, elevated D-dimer, low fibrinogen — using validated scoring systems (ISTH DIC score).