Description

• Disseminated intravascular coagulation (DIC) is an acquired syndrome that is always secondary to an underlying etiology.
• It is a systemic life-threatening process characterized by an uncontrolled activation of the coagulation and fibrinolytic systems with excessive thrombin generation and the consumption of coagulation factors and platelets.
• Widespread deposition of microthrombi can compromise perfusion and lead to organ failure.
• Ongoing activation and consumption of coagulant factors and platelets can result in diffuse and profuse bleeding.

Epidemiology

• Most commonly secondary to infections
• Overall incidence is difficult to determine secondary to the many conditions that cause DIC.

Pathophysiology

• Not a disorder in itself; occurs as a result of various initiating events
• Characterized by microvascular thrombosis and hemorrhage
• May be acute (e.g., meningococcemia) or chronic (e.g., malignancy/leukemia)
• There is a systemic intravascular deposition of fibrin as a result of increased thrombin generation, suppression of anticoagulant pathways, impaired fibrinolysis, and activation of inflammatory pathways.
• The initiation of coagulation activation leading to thrombin formation in DIC is mediated via the tissue factor/factor VIIa pathway.
• The tissue factor/factor VIIa pathway is activated via tissue factor expression from damaged endothelial cells.
• Anticoagulant pathways are diminished because of a decrease in the plasma levels of antithrombin and the protein C system through impaired production and increased destruction.
• The increase in fibrinolytic activity is likely secondary to the release of plasminogen activators from damaged endothelial cells.

Etiology

Most common causes are sepsis (particularly gram-negative), hypotensive shock, and trauma.

• Sepsis/severe infection
  • Bacterial: gram-negative and gram-positive
  • Malaria: Plasmodium falciparum
  • Fungal: Aspergillus
  • Rickettsial: Rocky Mountain spotted fever
  • Viral
• Trauma
  • Multiple fractures with fat emboli
  • Massive soft tissue injury
  • Severe head trauma
  • Multiple gunshot wounds
• Malignancies
  • Acute promyelocytic leukemia
  • Widespread solid tumors (e.g., neuroblastoma, adenocarcinoma)
• Obstetric
  • Retained intrauterine fetal demise
  • Preeclampsia/eclampsia
  • Amniotic fluid embolism
  • Abruptio placentae
  • Posthemorrhagic shock
• Neonatal
  • Necrotizing enterocolitis
  • Perinatal asphyxia
  • Amniotic fluid aspiration
  • Obstetric complications (see above)
  • Sepsis (bacterial and viral)
  • Erythroblastosis fetalis
  • Respiratory distress syndrome
• Vascular malformations
  • Kasabach-Merritt syndrome
  • Large vascular aneurysms
• Miscellaneous
  • Acute hemolytic transfusion reaction
  • Snake bite
  • Homozygous protein C/S deficiency (purpura fulminans)
  • Transplant rejection
  • Severe collagen vascular disease
  • Recreational drugs
  • Profound shock or asphyxia
  • Hypothermia or hyperthermia
  • Extensive burn injuries
  • Fulminant hepatitis/hepatic failure
  • Severe pancreatitis