Disseminated Intravascular Coagulation

Excessive and inappropriate activation of the haemostatic system

Aetiology

• Causes include sepsis, obstetric emergencies, malignancy, hypovolaemic shock

Pathophysiology

• Arises because of systemic activation of coagulation either by release of procoagulant material, such as tissue factor, or via cytokine pathways as part of the inflammatory response

• Such systemic activation leads to widespread generation of fibrin and deposition in blood vessels, leading to thrombosis and multiorgan failure

• Due to the widespread coagulation activation there is consumption of platelets and coagulation factors, and secondary activation of fibrinolysis leading to production of FDPs and D-dimer

• These further contribute to the coagulation defect by inhibiting fibrin polymerization

• The consequences of these changes are a mixture of initial thrombosis, followed by a bleeding tendency due to consumption of coagulation factors and dysregulated fibrinolytic activation
• Microvascular thrombus formation → end organ failure
• Clotting factor consumption → bruising, purpura, generalised bleeding

Clinical presentation

• Patient is often acutely ill and shocked

• Clinical presentation varies from no bleeding at all to profound haemostatic failure with widespread haemorrhage
• Bleeding may occur from the mouth, nose and venepuncture sites, and there may be widespread ecchymoses

• Thrombotic events - any organ may be involved but the skin, brain and kidneys are most often affected

Investigations

Bloods

• The PT, APTT and TT are usually very prolonged and the fibrinogen level is markedly reduced

• High levels of FDPs, including D-dimer, are found, owing to the intense fibrinolytic activity stimulated by the presence of fibrin in the circulation

• Severe thrombocytopenia

• The blood film may show fragmented red blood cells

Management

• Treat underlying cause

• Replacement therapy - platelet transfusions, plasma transfusions, fibrinogen replacement