Disseminated intravascular coagulation

Revision as of 05:16, 6 June 2015 by Rossdonaldson1 (talk | contribs) (Causes)

Background

  • Widespread and inappropriate activation of the coagulation and fibrinolytic systems
    • Exposure of blood to procoagulants such as tissue factor and cancer procoagulant
    • Formation of fibrin within the circulation
    • Fibrinolysis
    • Depletion of clotting factors
    • End-organ damage
  • Chronic DIC occurs when hepatic/bone marrow production balances coag factor consumption

Causes

  • Infection
    • Most common cause of DIC
    • 10%–20% of pts w/ Gram-neg sepsis have DIC
      • Septic pts more likely to have bleeding than thrombosis
    • More likely to develop in asplenic pts or cirrhosis
  • Carcinoma
    • DIC is often chronic and compensated
    • Thrombosis is more common than bleeding
  • Leukemia
    • More likely to have bleeding than thrombosis
  • Trauma
    • Brain injury, crush injury, burns, rhabdo, fat embolism
  • Liver disease
    • May have chronic compensated DIC; acute DIC may occur in setting of acute liver failure
  • Pregnancy
  • Envenomation
    • Rattlesnakes and other vipers
    • Bleeding not as serious as expected from lab values
  • ARDS
    • 20% of pts with ARDS develop DIC; 20% of pts with DIC develop ARDS
  • Transfusion reactions

Clinical Features

  • In given pt either bleeding or thrombosis will predominate
    • Bleeding is more common (65% of pts)
      • Ranges from petechiae/ecchymosis to life-threatening GI/CNS/pulm bleeding
      • Shock occurs in 15%
    • Renal failure (25-40%)
    • Hepatic dysfunction (19%)
    • Respiratory dysfunction (16%)
    • Thromboembolism (7%)
    • CNS involvement (2%)
    • Purpura fulminans (widespread arterial and venous thromboses)
      • Associated w/ significant bacteremia

Diagnosis

  • Acute DIC
    • Platlets
      • Low (or dropping)
      • Sn, not Sp
    • PT
      • Prolonged
    • Fibrinogen
      • Low
      • <100 correlates w/ severe DIC
      • May be normal (acute phase reactant)
    • PTT
      • Prolonged
    • FDP
      • Elevated
    • D-dimer
      • Elevated
      • Sn but not Sp: may also see in pts w/ chronic liver or renal disease
    • RBCs
      • Fragmented (not specific)
  • Chronic DIC
    • FDP: Elevated
    • D-dimer: Elevated
    • Platelet: Variable
    • Fibrinogen: Normal-elevated
    • PT: Normal
    • PTT: Normal
    • RBCs
      • Fragmented

DDX

  • TTP-HUS
    • Pts usually have little or no prolongation of PT or PTT
  • Severe liver disease
    • Also a/w prolonged PT/PTT, thrombocytopenia, incr D-dimer, incr FDPs
      • However, D-dimer is usually only mildly elevated
  • Heparin-induced thrombocytopenia

Thrombocytopenia

Decreased production

Increased platelet destruction or use

Drug Induced

Comparison by Etiology

ITP TTP HUS HIT DIC
↓ PLT Yes Yes Yes Yes Yes
↑PT/INR No No No +/- Yes
MAHA No Yes Yes No Yes
↓ Fibrinogen No No No No Yes
Ok to give PLT Yes No No No Yes

Treatment

  • Treat underlying illness
  • Replacement tx
    • Only indicated in pts w/ documented DIC + bleeding or impending procedure
      • Fibrinogen
        • Consider repletion w/ cryoprecipitate to raise level to 100-150
      • Platelets
        • Consider repletion if <50K w/ bleeding or <20K without bleeding
      • FFP
      • Vitamin K
      • Folate
    • Heparin
      • Consider only in pts w/ thromboembolic predominant symptoms from chronic DIC

See Also

References