DIC

• Disseminated intravascular coagulation (DIC) is a serious disorder occurring in response to an illness or disease process which results in dysregulated blood clotting.
• In DIC there is an inappropriate activation of clotting and/or fibrinolytic system

  Leads to tendency to both bleeding and thrombosis simultaneously
• Causes:

  • Shock
  • Sepsis/severe infection - massive release of pro-inflammatory cytokines that activate the coagulation cascade
  • Major trauma or burns
  • Malignancies - acute promyelocytic leukaemia is strongly associated
  • Obstetric emergencies - eclampsia, placental abruption
  • Severe immune-mediated reactions - haemolytic transfusion reaction
  • Severe organ dysfunction - acute hepatic failure and severe acute pancreatitis
• Pathophysiology:

  • Release of pro-inflammatory cytokines or pro-coagulant factors such as tissue factor
  • Intravascular activation of the coagulation cascade throughout the body
  • Microvascular thrombosis results due to the formation of fibrin webs and the activation and aggregation of platelets - multi organ failure due to tissue ischaemia
  • Concentration of available clotting factors falls - risk of bleeding
  • Platelets being used up - thrombocytopenia
• DIC can be acute or chronic. Acute DIC is the most common subtype, with rapid-onset conditions such as trauma, sepsis and haemolytic transfusion reactions. Chronic DIC tends to occur with less rapid-onset conditions such as cancer.
• History:

  • For a diagnosis of DIC to be made, there must be some objective evidence of a precipitating factor
• Typical symptoms:

  • Bleeding from unusual sites - ears, node, GI tract, respiratory tract or sites of venepuncture/cannulation
  • Bleeding from three unrelated sites is highly suggestive of DIC
  • Widespread or unexpected bruising without a history of trauma
  • New confusion or disorientation - microvascular thrombosis affecting cerebral perfusion
• Clinical exam findings:

  • Signs of haemorrhage: bleeding from cannula sites/venepuncture sites, melaena, haematemesis, rectal bleeding, epistaxis, haemoptysis, haematuria
  • Petechiae or purpura
  • Livedo reticularis - mottled lace like patterning of the skin
  • Purpura fulminans - widespread skin necrosis due to microvascular thrombosis leading to localised infarction
  • Localised infarction and gangrene e.g. of the fingers
  • Confusion
  • Signs of circulatory collapse - oliguria, hypotension and/or tachycardia
• ISTH scoring system:

  • The international society of thrombosis and haemostasis
  • Make the diagnosis of DIC more objective
  • Platelet count
  • D-dimer
  • Prothrombin time
  • Fibrinogen levels
• Lab investigations:

  • FBC - thrombocytopenia due to excessive platelet consumption
  • Coagulation screen - prolonged PT and/or APTT
  • Clauss fibrinogen - decreased as fibrinogen is converted to fibrin
  • D-dimer - raised, providing evidence of degradation of fibrin clots around the body
  • Other investigations depend on the underlying cause e.g. blood cultures in sepsis
• Management:

  • Transfusion should be based on whether the patient is actively bleeding
  • Platelet transfusions should be considered if the patient is bleeding to maintain >50
  • In bleeding patients with a prolonged PT and/or APTT, fresh frozen plasma can be considered
  • Concentrated solutions of clotting factors such as prothrombin complex concentrate
  • If there is severely low fibrinogen then transfusions of cryoprecipitate should be considered
  • If thrombosis is a prominent feature - therapeutic doses of heparin
• Complications:

  • Multi-organ failure
  • Life-threatening haemorrhage
  • Cardiac tamponade - bleeding into the pericardial space
  • Haemothorax - bleeding into the pleural space
  • Intracranial haemorrhage
  • Gangrene and loss of digits