Disseminated intravascular coagulation

Background

• Systemic microvascular coagulation leading to organ dysfunction and depletion of clotting factors and platelets

Etiologies

• Sepsis, from gram-negative bacteria, gram-positive bacteria, some viruses, and some parasites (including malaria)
• Trauma, particularly brain trauma
• Organ destruction e.g pancreatitis
• Malignancy
  • Solid tumour, especially mucinous tumours (pancreatic, gastric, ovarian) and brain tumours
  • Leukaemia, especially promyelocytic leukemia
• Obstetric complications
  • Amniotic fluid embolism
  • Placental abruption
  • Pre-eclampsia
  • Acute fatty liver of pregnancy
• Vascular abnormalities
  • Large haemangiomata
  • Vascular aneurysm
• Severe liver failure
• Toxic and immunological insults
  • Snake bite
  • Recreational drug use
  • Acute hemolytic transfusion reaction from ABO incompatibility
  • Transplant rejection

Differential Diagnosis

• Thrombotic microangiopathies, including TTP and HUS
• Severe liver failure
• Heparin-induced thrombocytopenia
• Catastrophic antiphospholipid syndrome

Investigations

• Thrombocytopenia is the most sensitive (Sn 98%)
• D-dimer also sensitive, but not specific
• Elevated INR/PTT (Sn 50-60%), but can be normal
• Low fibrinogen is not very sensitive (Sn 28%), but serial measurement may be helpful
• Blood film may show fragments

ISTH Diagnostic Scoring System

• Only useful in the context of an underlying disorder known to be associated with overt DIC
• Needs PT, platelet count, fibrinogen, and fibrin-related marker (e.g. D-dimer)

Marker	Value	Score
Platelet count	>100 <100 <50	0 1 2
Elevated fibring marker (e.g. D-dimer, fibrin degradation products)	no increase moderate increase strong increase	0 2 3
Prolonged PT	<3 sec >3 sec >6 sec	0 1 2
Fibrinogen level	>1 g/L <1 g/L	0 1

Interpretation

• ≥5 compatible with over DIC: repeat score daily
• <5 suggestive for non-overt DIC: repeat in next 1-2 days

Management

• Treat the underlying cause!

Transfusions

• Only supplement blood products if they are actively bleeding, or to prepare them for an invasive procedure that may cause bleeding

Platelets

• Platelets to target ≥50 if bleeding
• Platelets not needed if not bleeding unless otherwise at risk
  • Weak evidence to target 10-20

Plasma and components

• May be indicated in bleeding patients with PT or aPTT >1.5x normal or fibrinogen <1.5 g/L
• FFP 15-30 ml/kg can correct the coagulopathy
• PCC lacks Factor V and may worsen coagulopathy due to trace amounts of active factors
• Fibrinogen 3 g should raise the plasma fibrinogen by about 1 g/L
  • Can be given as 4 units FFP, 2 units pooled cryoprecipitate, or 3 g fibrinogen concentrate

Anticoagulation

• In cases of severe thrombosis, including arterial or venous thromboembolism, severe purpura fulminans associated with acral ischemia or vascular skin infarction, consider unfractionated heparin (UFH)
  • Target a PTT 1.5-2.5x normal
  • Monitor closely for bleeding
• Other patients still need DVT prophylaxis with heparin or LMWH

Further Reading

1. Wada H et al. Guidance for diagnosis and treatment of disseminated intravascular coagulation from harmonization of the recommendations from three guidelines. J Thromb Haemost. 2013;11:761–767.