A 52-year-old man with sepsis secondary to gram-negative bacteremia develops DIC with severe thrombocytopenia (platelets 15,000/μL), prolonged PT/aPTT, and fibrinogen 120 mg/dL. After aggressive fluid resuscitation and broad-spectrum antibiotics, his coagulopathy persists. Which anticoagulant is the drug of choice for DIC in this setting?

Explanation

## Anticoagulation in Sepsis-Induced DIC **Key Point:** Unfractionated heparin (UFH) is the drug of choice for anticoagulation in DIC, particularly in sepsis, because it is rapidly reversible and allows precise monitoring and control. ### Rationale for UFH in DIC #### 1. **Reversibility** - UFH has a half-life of 60–90 minutes; effects wear off quickly if bleeding occurs. - Protamine sulfate can reverse UFH immediately if needed. - Critical in DIC where bleeding risk is high. #### 2. **Monitoring** - aPTT can be monitored continuously to titrate dosing. - In DIC, baseline aPTT is already prolonged, making monitoring challenging but still possible with serial measurements. #### 3. **Mechanism in DIC** - UFH inhibits thrombin (Factor IIa) and Factor Xa, reducing both thrombosis and consumption of clotting factors. - Prevents further microthrombi formation while allowing fibrinolysis to proceed. ### Comparison of Anticoagulants in DIC | Agent | Reversibility | Monitoring | Use in DIC | |-------|---------------|------------|----------| | **UFH** | Immediate (protamine) | aPTT | **First-line** | | **LMWH** | Partial (protamine 50%) | Anti-Xa | Avoid (prolonged half-life, irreversible) | | **Warfarin** | Slow (vitamin K, FFP) | INR | Contraindicated (slow onset, not reversible quickly) | | **Fondaparinux** | None | Anti-Xa | Contraindicated (no reversal agent) | | **DOACs** | Minimal/none | None | Contraindicated (no rapid reversal in DIC) | **High-Yield:** Low-dose UFH (5–10 U/kg/hr) is often used in DIC rather than therapeutic doses, balancing anticoagulation against bleeding risk. **Clinical Pearl:** In DIC, the decision to anticoagulate depends on the balance between thrombotic and hemorrhagic manifestations. UFH is chosen when anticoagulation is deemed necessary because it offers the greatest safety margin. ### When to Use Heparin in DIC - Predominant thrombotic manifestations (acral necrosis, venous thromboembolism). - Chronic DIC with ongoing thrombin generation. - After initial hemostatic support (FFP, cryoprecipitate, platelets) has been given.