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)
• Carcinoma
• Leukemia
• Trauma
  • Brain injury, crush injury, burns, rhabdo, fat embolism
• Liver disease
• Pregnancy
  • Abruption, Amniotic Fluid Embolus, septic abortion, HELLP syndrome
• Snake bite
• ARDS
• Transfusion reaction

Clinical Features

In given pt either bleeding or thrombosis will predominate (bleeding is more common ~65%)

• Shock (15%)
• Acute renal failure (25-40%)
• Hepatic dysfunction (19%)
• Respiratory dysfunction (16%)
• Thromboembolism (7%)
• CNS involvement (2%)
• Purpura fulminans (widespread arterial and venous thromboses)
  • Associated with significant bacteremia

Differential Diagnosis

• 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

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

Diagnosis

Acute

• 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

• FDP: Elevated
• D-dimer: Elevated
• Platelet: Variable
• Fibrinogen: Normal-elevated
• PT: Normal
• PTT: Normal
• RBCs
  • Fragmented

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)