Disseminated intravascular coagulation

Background

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

Causes

1. Infection
   1. Most common cause of DIC
   2. 10%–20% of pts w/ Gram-neg sepsis have DIC
      1. Septic pts more likely to have bleeding than thrombosis
   3. More likely to develop in asplenic pts or cirrhosis
2. Carcinoma
   1. DIC is often chronic and compensated
   2. Thrombosis is more common than bleeding
3. Leukemia
   1. More likely to have bleeding than thrombosis
4. Trauma
   1. Brain injury, crush injury, burns, rhabdo, fat embolism
5. Liver disease
   1. May have chronic compensated DIC; acute DIC may occur in setting of acute liver failure
6. Pregnancy
   1. Abruption, amniotic fluid embolus, septic abortion, HELLP syndrome
7. Envenomation
   1. Rattlesnakes and other vipers
   2. Bleeding not as serious as expected from lab values
8. ARDS
   1. 20% of pts with ARDS develop DIC; 20% of pts with DIC develop ARDS
9. 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

1. Acute DIC
   1. Platlets
      1. Low (or dropping)
      2. Sn, not Sp
   2. PT
      1. Prolonged
   3. Fibrinogen
      1. Low
      2. <100 correlates w/ severe DIC
      3. May be normal (acute phase reactant)
   4. PTT
      1. Prolonged
   5. FDP
      1. Elevated
   6. D-dimer
      1. Elevated
      2. Sn but not Sp: may also see in pts w/ chronic liver or renal disease
   7. RBCs
      1. Fragmented (not specific)
2. Chronic DIC
   1. FDP: Elevated
   2. D-dimer: Elevated
   3. Platelet: Variable
   4. Fibrinogen: Normal-elevated
   5. PT: Normal
   6. PTT: Normal
   7. RBCs
      1. Fragmented

DDX

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

Treatment

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

Source

Tintinalli