Disseminated Intravascular Coagulation - DIC

Disseminated Intravascular Coagulation - DIC

 

Disseminated intravascular coagulation (DIC) is a disorder characterized by massive systemic activation of coagulation with consumption of platelets and coagulation proteins.

Epidemiology

  • Incidence – >18,000 cases/year in U.S.

Risk Factors

  • Sepsis (bacterial, viral, fungal)
  • Trauma (polytrauma, fat embolism, burns)
  • Malignancy (solid tumors, myeloproliferative malignancies)
  • Obstetric complications (abruptio placentae, placenta previa, amniotic fluid embolus)
  • Toxic reactions (snake bites)
  • Immunologic reactions (hemolytic transfusion reaction, transplant rejection)
  • Organ destruction (pancreatitis, hepatic failure)

Pathophysiology

  • Activation of the inflammatory pathway via cytokines
  • Suppression of physiologic anticoagulant pathways
  • Systemic generation of thrombin
  • Impaired fibrinolysis

Clinical Presentation

  • Hemorrhage – petechiae, purpura, epistaxis, mucous membrane bleeding
  • Thrombosis
    • May lead to organ failure
  • Chronic DIC occurs in cancer patients
    • Primary symptom is thrombosis
    • Referred to as Trousseau syndrome

Diagnosis

  • Patient has risk factors for DIC
  • CBC –  may demonstrate decreased platelets
  • Prolonged clotting times
    • PT – increased (may be normal in chronic DIC)
    • PTT – increased (may be normal in chronic DIC)
    • Thrombin time – increased
  • Increased levels of fibrin-related markers
    • D-dimer – increased in acute and chronic DIC
  • Decreased – coagulation elements
    • Platelet count – decreased
    • Fibrinogen – decreased, but an acute phase reactant so it may not decrease until DIC is severe
Coagulation Test Scoring

Scoring system for DIC proposed by ISTH, International Society on Thrombosis and Hemostasis
Score 0 1 2 3
Platelet count (x109/L) >100 <100 <50  
PT (seconds) <3 >3 but <6 ≥6  
Fibrinogen (g/L) >1 <1    
Fibrin-related markers* (increase) No increase   Moderate increase Strong increase
TOTAL If ≥5, compatible with overt DIC - repeat scoring daily. If <5, suggestive of non-overt DIC - repeat scoring after 1-2 days.
*Cutoffs for scoring fibrin-related markers must be established for the specific assay.
(Adapted with permission from Franchini, et al., 2006, 6)

Risk Assessment

  • Does the patient have an underlying disorder known to be associated with DIC?
    • If no – stop
    • If yes – check coagulation tests
  • Order coagulation tests
    • Platelet count, prothrombin time (PT), D-dimer and fibrinogen level
  • Score global coagulation test results
  • D-dimer measurements alone have excellent negative predictive value for ruling out DIC

Differential Diagnosis

  • Idiopathic thrombocytopenic purpura
  • Hemolytic uremic syndrome
  • Thrombotic thrombocytopenic purpura
  • Severe liver disease
  • Malignancy

Treatment

  • Treat underlying disorder causing DIC
  • Replacement therapy until disorder resolved
    • Platelets
    • Fresh frozen plasma
  • Patients with chronic DIC and thrombosis may require heparin therapy

 


See Also