How to manage a subdural hematoma with a drop in Glasgow Coma Scale (GCS) in a patient on Warfarin (coumarin)

Management of Subdural Hematoma with GCS Drop in a Warfarin-Anticoagulated Patient

Immediately discontinue warfarin and urgently reverse anticoagulation with 4-factor prothrombin complex concentrate (4F-PCC) at 25-50 IU/kg plus intravenous vitamin K 5-10 mg to achieve INR <1.5, while simultaneously obtaining neurosurgical consultation. 1, 2

Immediate Reversal Protocol

Administer 4F-PCC without waiting for INR results if intracranial hemorrhage is suspected based on clinical deterioration (GCS drop). 2 The dosing is weight-based and INR-dependent:

• For INR ≥2.0: Use 25-50 IU/kg 2
• For INR 1.3-2.0: Consider lower dose of 10-20 IU/kg 2

Always give intravenous vitamin K (5-10 mg) alongside PCC to prevent rebound increases in INR over the subsequent 12-24 hours. 1, 2 This combination targets INR correction to <1.5. 1, 2

Why 4F-PCC Over Fresh Frozen Plasma

4F-PCC is superior to FFP for warfarin reversal in this emergency setting because: 3

• Fast reconstitution into smaller volume (20-30 minute infusion vs hours for FFP) 3
• No requirement for ABO compatibility testing or thawing 3
• Reduced risk of transfusion-associated circulatory overload and transfusion-related acute lung injury 3
• Rapid INR correction within 4 hours is associated with lower in-hospital mortality 2

Historical data demonstrates that rapid reversal (within 1.9 hours) reduces mortality from 48% to 10% in warfarin-anticoagulated trauma patients with intracranial hemorrhage. 4

Immediate Diagnostic Steps

Obtain non-contrast head CT immediately to confirm the subdural hematoma and assess for mass effect, midline shift, and other intracranial injuries. 1

Check coagulation parameters immediately: INR, PT, aPTT, and fibrinogen. 1 However, do not delay reversal while waiting for laboratory results if clinical suspicion is high based on GCS deterioration. 1

Recheck INR after administering reversal agents to confirm adequate correction to <1.5. 1

Neurosurgical Management

Obtain immediate neurosurgical consultation for all patients with confirmed subdural hematoma on anticoagulation, especially with GCS drop indicating clinical deterioration. 1 Surgical evacuation may be necessary depending on:

• Hematoma size and location 1
• Degree of midline shift 5
• Rate of clinical deterioration 1
• Response to medical management 1

Critical Monitoring Protocol

Obtain repeat head CT within 24 hours, as anticoagulated patients have a 3-fold increased risk of hemorrhage expansion (26% vs 9% in non-anticoagulated patients). 1, 6

Monitor neurologically with documented half-hourly checks until stable. 1 Any further neurological deterioration requires immediate repeat CT imaging. 1

Consider CT angiography to identify patients at risk for hematoma expansion based on contrast extravasation (spot sign). 1

Additional Hemostatic Measures

Consider tranexamic acid 1g IV over 10 minutes if treatment can be given within 3 hours of symptom onset, which reduces head injury-related death with a risk ratio of 0.78 (95% CI 0.64-0.95). 1, 6

If fibrinogen is <150 mg/dL after reversal, administer additional cryoprecipitate. 1

Common Pitfalls to Avoid

• Do not use fresh frozen plasma as first-line therapy when 4F-PCC is available—it is slower, requires larger volumes, and increases risk of volume overload. 3
• Do not use recombinant activated factor VII (rFVIIa) as first-line therapy due to increased thromboembolic risk, especially in elderly patients. 2 While one case report showed success 7, guidelines do not support this approach.
• Do not delay reversal waiting for INR results if clinical deterioration suggests intracranial hemorrhage. 1
• Be aware that higher doses of PCC (>2000-3000 IU total) may increase venous thromboembolism risk—consider the patient's underlying thrombotic risk factors. 2
• Neither initial GCS nor INR reliably identifies which patients will have hemorrhage progression—all require aggressive reversal and monitoring. 4

Evidence on Target INR

While traditional teaching targets INR <1.3, mild INR elevations of 1.31-1.69 at 24 hours are not associated with markedly increased risk of subdural hematoma expansion. 5 However, given the acute GCS drop in your scenario, aggressive reversal to INR <1.5 remains the standard of care to minimize ongoing hemorrhage expansion. 1, 2

Anticoagulation Resumption Considerations

The decision to restart anticoagulation should balance thromboembolic risk against recurrent hemorrhage risk. 2 Limited data suggest reinstitution of warfarin after 7-10 days may be safe in selected patients, but this requires individualized assessment with neurosurgery and cardiology/hematology input. 2 Note that reversal carries a 7.2-12% risk of thromboembolic events within 30 days. 3