Disseminated intravascular coagulation

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
  • Abruption, Amniotic Fluid Embolus, septic abortion, HELLP syndrome
• 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

• Marrow infiltration (tumor or infection)
• Viral infections (rubella, HIV)
• Marrow suppression (commonly chemotherapy or radiation)
• Congenital thrombocytopenia
  • Fanconi anemia
  • Alport syndrome
  • Bernand Soulier
• Vitamin B12 and/or folate deficiency

Increased platelet destruction or use

• Idiopathic thrombocytopenic purpura
• Thrombotic Thrombocytopenic Purpura (TTP)
• Hemolytic Uremic Syndrome (HUS)
• Disseminated Intravascular Coagulation (DIC)
• Viral infections (HIV, mumps, varicella, EBV)
• Drugs (heparin, protamine)
• Postransfusion or Posttransplantation
• Autoimmune destruction (SLE or Sarcoidosis)
• Mechanical destruction
  • Artificial valves
  • ECMO
• HELLP syndrome
• Excessive hemorrhage
• Hemodialysis, extracorporeal circulation
• Splenic Sequestration
  • Occurs in Sickle cell disease and Cirrhosis

Drug Induced

• sulfa antibiotics, ETOH, ASA, thiazide diuretics/furosemide

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

• Coagulopathy (Main)