What are the investigations and treatment for a patient suspected of having Disseminated Intravascular Coagulation (DIC)?

Investigations and Management of Suspected Disseminated Intravascular Coagulation (DIC)

For suspected DIC, perform immediate laboratory testing including platelet count, prothrombin time (PT), fibrinogen level, and D-dimer, then treat the underlying cause while providing blood product support based on bleeding status and laboratory parameters. 1, 2

Diagnostic Approach

Laboratory Investigations

• Essential tests for DIC diagnosis:

  • Complete blood count with platelet count
  • Prothrombin time (PT)/INR
  • Fibrinogen level
  • D-dimer or fibrin degradation products (FDP)
  • Peripheral blood smear (to look for schistocytes)

• ISTH Overt DIC Scoring System 1:

  Parameter	Score	Range
  Platelet count (×10⁹/L)	2	<50
  	1	≥50, <100
  Fibrin-related markers (D-dimer/FDP)	3	Strong increase
  	2	Moderate increase
  Prothrombin time (PT)	2	≥6 seconds prolongation (PT ratio >1.4)
  	1	≥3 seconds, <6 seconds prolongation (PT ratio >1.2, ≤1.4)
  Fibrinogen (g/L)	1	<1.0

  • Score ≥5 confirms DIC diagnosis

Key Diagnostic Considerations

• Monitor trends in laboratory values - a 30% or higher drop in platelet count may indicate subclinical DIC even without clinical manifestations 2
• In cancer patients, a normal platelet count despite a profound decrease from a very high level may be the only sign of DIC 2
• PT and PTT may not be prolonged in subclinical forms of DIC, especially in cancer-associated cases 2
• The combination of D-dimer and FDP tests has the highest diagnostic efficiency (95%) 3

Treatment Algorithm

1. Treat the Underlying Cause

• This is the cornerstone of DIC management 4
• Examples include:
  • Antibiotics for sepsis
  • Chemotherapy for acute promyelocytic leukemia
  • Surgery for obstetric complications
  • Removal of necrotic tissue in trauma

2. Supportive Care with Blood Products

For Patients with Active Bleeding:

• Platelet transfusion:

  • Maintain platelet count above 50 × 10⁹/L 2, 1
  • For CNS injury or multiple trauma, target >100 × 10⁹/L 1

• Fresh frozen plasma (FFP):

  • Administer 15-30 mL/kg with careful clinical monitoring 2
  • Consider prothrombin complex concentrates if volume overload is a concern 2

• Fibrinogen replacement:

  • If fibrinogen remains <1.5 g/L despite other measures, administer:
    • Two pools of cryoprecipitate (when available) OR
    • Fibrinogen concentrate 2

For Patients at High Risk of Bleeding (Surgery/Invasive Procedures):

• Platelet transfusion:

  • If platelet count <30 × 10⁹/L in acute promyelocytic leukemia 2
  • If platelet count <20 × 10⁹/L in other cancers 2

• Before high-risk procedures with PT prolonged >4 seconds:

  • Target fibrinogen >1.0 g/L using cryoprecipitate if needed 1
  • Maintain platelet count >50 × 10⁹/L (>100 × 10⁹/L for neurosurgery) 1

3. Anticoagulant Therapy

• For thrombosis-predominant DIC:

  • Consider therapeutic doses of heparin for:
    • Arterial or venous thromboembolism
    • Severe purpura fulminans with acral ischemia
    • Vascular skin infarction 4
  • Continuous infusion unfractionated heparin (10 μ/kg/h) may be preferred when bleeding risk coexists 4

• For non-bleeding critically ill patients with DIC:

  • Provide thromboprophylaxis with prophylactic doses of heparin or LMWH 4

Important Clinical Caveats

• Avoid common pitfalls:

  1. Do not transfuse blood products based solely on laboratory values without clinical bleeding 1, 4
  2. Recognize that normal PT/aPTT does not exclude DIC, especially in subclinical forms 1
  3. Monitor laboratory parameters frequently as DIC is a dynamic process 4
  4. Be aware that in cancer patients, a decreasing platelet trend may be the only sign of DIC, even if counts remain in normal range 2
  5. Avoid antifibrinolytic agents in general DIC cases 4

• Special considerations:

  • In cancer-related DIC, the frequency of monitoring should be decided case by case (from monthly to daily) 2
  • In patients with liver disease, be cautious about overdiagnosing DIC as laboratory profiles can be similar 1
  • For patients with severe sepsis and DIC, recombinant human activated protein C may be considered (24 μg/kg/h for 4 days) if no high bleeding risk 4

By following this structured approach to diagnosis and management, patients with suspected DIC can receive prompt, appropriate care that addresses both the underlying cause and the coagulation abnormalities.