ISTH DIC Score
Severe sepsis with overt DIC
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Evidence-based calculations Used in clinical settings worldwide Regular monitoring recommended
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⚠️ Overt DIC - Sepsis
Severe sepsis with overt DIC
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🔍 Non-Overt DIC
Early/compensated DIC
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🤰 Obstetric DIC
DIC in pregnancy - placental abruption
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🩸 APL-Associated DIC
Acute promyelocytic leukemia
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🚨 Trauma-Induced DIC
Major trauma with coagulopathy
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📊 Borderline Score
Uncertain diagnosis
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✅ Normal Coagulation
No DIC present
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📈 Chronic DIC
Compensated chronic DIC
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Laboratory Values
Clinical Context
For informational purposes only — not medical advice. Consult a healthcare professional before acting on results.
🏥 Health Facts
— WHO
— CDC
Understanding Disseminated Intravascular Coagulation (DIC)
DIC is an acquired syndrome characterized by widespread activation of coagulation, resulting in intravascular formation of fibrin and thrombotic occlusion of small and midsize vessels. Simultaneously, consumption of platelets and coagulation factors leads to bleeding complications. DIC is always secondary to an underlying disorder.
Consumption
Platelets and clotting factors are consumed faster than they can be replaced
Bleeding
Depleted factors lead to spontaneous bleeding from multiple sites
Thrombosis
Microthrombi cause organ damage and ischemia
Fibrinolysis
Secondary fibrinolysis generates D-dimer and FDPs
ISTH Overt DIC Scoring System
| Parameter | 0 Points | 1 Point | 2 Points | 3 Points |
|---|---|---|---|---|
| Platelet Count | ≥100 × 10⁹/L | 50-99 × 10⁹/L | <50 × 10⁹/L | - |
| D-dimer/FDP | Normal | - | Moderate ↑ | Strong ↑ |
| PT Prolongation | <3 seconds | 3-6 seconds | ≥6 seconds | - |
| Fibrinogen | ≥1.0 g/L | <1.0 g/L | - | - |
Score 0-2
DIC unlikely. Repeat in 1-2 days if clinical suspicion persists.
Score 3-4
Suggestive of non-overt DIC. Repeat score daily.
Score ≥5
Compatible with overt DIC. Treat and repeat score daily.
Common Causes of DIC
Sepsis/Infection
- • Bacterial sepsis (gram-negative and positive)
- • Viral hemorrhagic fevers
- • Malaria
Most common cause (30-50% of DIC cases); often presents with both bleeding and thrombosis
Trauma/Surgery
- • Major surgery
- • Burns
- • Head injury
Acute onset; severity correlates with tissue damage extent
Obstetric
- • Placental abruption
- • Amniotic fluid embolism
- • HELLP syndrome
Can be rapidly progressive; high mortality if untreated
Malignancy
- • Acute promyelocytic leukemia (APL)
- • Mucin-secreting adenocarcinomas
- • Solid tumors with metastases
May be chronic and compensated; APL has unique features
Vascular
- • Aortic aneurysm
- • Giant hemangioma (Kasabach-Merritt)
- • Vasculitis
Often localized coagulopathy initially
Other
- • Snake envenomation
- • Transfusion reactions
- • Drug reactions
Variable presentation depending on cause
Treatment Principles
🎯 Treat Underlying Cause
The most important intervention is aggressive treatment of the underlying condition. DIC will not resolve while the inciting cause persists.
- • Antibiotics for sepsis
- • Delivery for obstetric causes
- • Chemotherapy for APL
- • Surgical intervention for trauma
💉 Supportive Transfusion
- Platelets: Target ≥50 × 10⁹/L if bleeding; ≥20 if not
- FFP: 15-20 mL/kg if PT prolonged with bleeding
- Cryoprecipitate: If fibrinogen <1.5 g/L
- Fibrinogen concentrate: Alternative to cryo
Laboratory Test Interpretation
| Test | Expected in DIC | Differential Considerations |
|---|---|---|
| Platelets | ↓↓ Decreased (consumption) | TTP, HIT, ITP, bone marrow failure |
| D-dimer/FDPs | ↑↑↑ Markedly elevated | VTE, surgery, inflammation, malignancy |
| PT/INR | ↑ Prolonged | Liver disease, vitamin K deficiency, warfarin |
| aPTT | ↑ Prolonged (usually) | Heparin, lupus anticoagulant, factor deficiency |
| Fibrinogen | ↓ Decreased | May be normal early (acute phase reactant) |
| Schistocytes | Present on smear | MAHA, TTP, HUS, mechanical valves |
Anticoagulation Considerations
When to Consider Anticoagulation
- • Thrombosis predominant features (organ ischemia)
- • Venous thromboembolism
- • Purpura fulminans
- • Arterial thrombosis
- • After bleeding controlled
When to Avoid Anticoagulation
- • Active life-threatening bleeding
- • Severe thrombocytopenia (<20,000)
- • CNS hemorrhage
- • Recent major surgery
- • Critical hypofibrinogenemia
Note: If anticoagulation is indicated, use unfractionated heparin at low doses (300-500 U/hour without bolus). Avoid LMWH due to renal clearance and prolonged effect. Monitor anti-Xa levels if possible.
Prognosis and Outcomes
Better Prognosis
- • Rapid identification of cause
- • Treatable underlying condition
- • Non-overt DIC (early intervention)
- • Obstetric causes (after delivery)
- • Lower ISTH score
Intermediate Prognosis
- • Trauma-related
- • Surgical complications
- • Controlled sepsis
- • Responding to treatment
Poor Prognosis
- • Refractory septic shock
- • Multi-organ failure
- • Intractable underlying cause
- • ISTH score ≥7
- • Progressive despite treatment
Overall Mortality: DIC carries 40-80% mortality depending on underlying cause and severity. Mortality is primarily driven by the underlying condition rather than DIC itself. Early recognition and aggressive treatment of the cause are the most important prognostic factors.
Special Situations
APL-Associated DIC
- • Unique combination of DIC + hyperfibrinolysis
- • Start ATRA immediately upon suspicion
- • Aggressive platelet/FFP support
- • Target fibrinogen >1.5 g/L, platelets >30-50k
- • Avoid heparin
- • Consider tranexamic acid
Obstetric DIC
- • Delivery is definitive treatment
- • Aggressive replacement during/after delivery
- • Higher fibrinogen targets (>2 g/L)
- • Watch for PPH complications
- • HELLP: consider steroids
- • AFE: supportive care, high mortality
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