Disseminated Intravascular Coagulation (DIC)

Question 1

Define disseminated intravascular coagulation (DIC)

Answer 1

DIC is an acquired syndrome characterised by activation of coagulation pathways, resulting in formation of intravascular thrombi and depletion of platelets and coagulation factors.

Question 2

Explain the aetiology of disseminated intravascular coagulation (DIC)

Answer 2

• DIC usually results from exposure of tissue factor to blood, initiating the coagulation cascade.
• This initiates primary haemostasis (platelet plug formation) and secondary haemostasis (clotting factor cascade to produce fibrin which stabilises the platelet plug)
• There is increased clotting and delayed fibrinolysis in the acute phase leading to persistence of microvascular thrombi and its sequelae (MAHA & Organ damage) –> fibrinolysis eventually takes place and clots are dissolved
• Eventually platelets and clotting factors will be consumed, leading to severe bleeding

In Chronic Non-Overt DIC, the body has time to compensate for the depletion of platelets, by inducing a hypercoagulable state —> DVTs are common

Question 3

Explain the risk factors of disseminated intravascular coagulation (DIC)

Answer 3

Anything that increases/exposes Tissue factor in the blood can lead to DIC:

• Sepsis/Serious infections - neutrophils and macrophages produce tissue factor
• Obstetric complications result in amniotic tissue factor entering Maternal circulation
  
  • Abruptio placentae (premature separation of implanted placenta)
  • Amniotic fluid embolism: amniotic fluid embolises into maternal circulation
• Severe organ destruction/failure (acute pancreatitis)
• Malignancies (Mucus-producing Adenocarcinomas pancreas/prostate/lung, AML)
• Severe toxic/immunologic reaction: Blood-tranfusion reaction, transplant rejection

Question 4

Recognise the presenting symptoms of disseminated intravascular coagulation (DIC)

Answer 4

Most likely presentation will be a severe acute event that will go on to have MASSIVE bleeding

Symptoms of underlying cause:

Bleeding from every orifice

• Petechiae/Purpura/Ecchymoses
• Bleeding from puncture site (e.g. cannula)
• Haematuria
• GI bleed
• Menorrhagia
• Epistaxis

Question 5

Recognise the signs of disseminated intravascular coagulation (DIC) on physical examination

Answer 5

• Signs of underlying cause
• Bleeding:
  
  • Petechiae/Purpura/Ecchymoses
  • Bleeding from puncture site (e.g. cannula)
  • Haematuria
  • GI bleed
  • Menorrhagia
  • Epistaxis
• MAHA signs:
  
  • Jaundice
  • Conjunctival and/or nail pallor

Question 6

Identify appropriate investigations for disseminated intravascular coagulation (DIC) and interpret the results

Answer 6

• Platelet count: Decreased
• Prothrombin time/aPTT: Both increased
• Bleeding time: Increased
• Fibrinogen: Decreased (all converted to fibrin)
• FDP/D-dimer: Increased
• Clotting factors (5,8,10,12): decreased
• Peripheral smear: Schistocytes

Question 7

Management

Answer 7

The cornerstone of the treatment of DIC is treatment of the underlying condition.

• Transfusion of platelets or plasma (components) be reserved for patients who present with bleeding
• should not primarily be based on laboratory results and should in general .