What is the management approach for a patient with suspected subdural hemorrhage, possibly taking anticoagulant medications such as warfarin (Coumadin), aspirin, or novel oral anticoagulants (NOACs)?

Management of Subdural Hemorrhage in Anticoagulated Patients

All patients with suspected subdural hemorrhage on anticoagulants require immediate non-contrast head CT, urgent discontinuation of anticoagulation, and rapid reversal with specific agents based on the anticoagulant type. 1, 2

Immediate Diagnostic Evaluation

• Obtain immediate non-contrast head CT in all patients on anticoagulants (warfarin, NOACs) or antiplatelet agents who sustain head trauma, regardless of mechanism severity or presence of symptoms 2
• Anticoagulated patients have a 2.6-fold increased risk of significant intracranial injury (3.9% vs 1.5% in non-anticoagulated patients) 3, 2
• Warfarin carries the highest risk at 10.2% for intracranial hemorrhage, while NOACs carry a 2.6% risk 3, 2
• Check INR, PT, aPTT, and fibrinogen levels immediately upon presentation 1

Anticoagulation Reversal Protocol

For Warfarin-Associated Subdural Hemorrhage

• Immediately discontinue warfarin and administer 4-factor prothrombin complex concentrate (4F-PCC) plus 5mg intravenous vitamin K to achieve INR <1.5 4, 1, 2
• 4F-PCC is superior to fresh frozen plasma for rapid reversal, achieving INR ≤1.2 within 3 hours in 67% of patients versus 9% with FFP 4
• Recheck INR after reversal agents are administered to confirm adequate reversal 1

For NOAC-Associated Subdural Hemorrhage

• For apixaban or rivaroxaban (factor Xa inhibitors): administer andexanet alfa as the specific reversal agent 4, 3, 2
• For dabigatran (direct thrombin inhibitor): administer idarucizumab for rapid reversal 4, 2
• Treatment should be administered when clinically significant anticoagulant levels are suspected based on type and timing of dosing, rather than waiting for blood test results 4

For Enoxaparin (LMWH)-Associated Subdural Hemorrhage

• Reverse therapeutic-dose enoxaparin with protamine sulfate administered by slow IV injection over 10 minutes 1
• If enoxaparin was given within 8 hours: administer 1 mg protamine per 1 mg of enoxaparin (maximum single dose 50 mg) 1
• If enoxaparin was given within 8-12 hours: administer 0.5 mg protamine per 1 mg of enoxaparin 1
• After 3-5 half-lives have elapsed, protamine is probably not needed 1
• Do not use protamine for fondaparinux reversal—it is ineffective 1

For Aspirin or Antiplatelet-Associated Subdural Hemorrhage

• Aspirin monotherapy alone does not significantly increase risk (relative risk 1.29,95% CI 0.88-1.87) and is not considered a mandatory factor requiring reversal by itself 2
• Combined aspirin and clopidogrel therapy carries the highest risk with a relative risk of 2.88 for significant intracranial injury 2
• Concomitant aspirin use in small numbers did not appear to be associated with initial or delayed intracranial hemorrhage in warfarin or clopidogrel patients 4

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, 3, 2
• If fibrinogen is less than 150 mg/dL after reversal, administer additional cryoprecipitate 1
• If thrombolytic agents were recently administered (within 24 hours), administer cryoprecipitate 10 units as initial dose 1

Neurosurgical Consultation and Monitoring

• Obtain immediate neurosurgical consultation for all patients with confirmed subdural hemorrhage on anticoagulation 1, 2
• Surgical intervention may be necessary depending on hemorrhage location, size, and clinical deterioration 1
• No patient with an initial subdural hematoma ≤3 mm required surgery initially or in follow-up, although 11.1% enlarged (maximum width 10 mm) 5
• An 8.5-mm initial subdural hematoma size threshold best predicted the need for surgical intervention (AUC 0.81) 5

Repeat Imaging Protocol

• Obtain repeat head CT within 24 hours, as anticoagulated patients have a 3-fold increased risk of hemorrhage expansion (26% versus 9% in non-anticoagulated patients) 1, 3, 2
• Consider CT angiography to identify patients at risk for hematoma expansion based on contrast extravasation 1
• Monitor neurologically with documented half-hourly checks until stable 1
• Any neurological deterioration requires immediate repeat CT imaging 1

Risk Factors for Hematoma Expansion

• Larger initial subdural hematoma size, concurrent subarachnoid hemorrhage, hypertension, convexity location, and midline shift are significantly associated with hematoma expansion 5
• Earlier reversal of VKA-related intracranial hemorrhage (<4 hours to goal INR <1.3) combined with blood pressure control was associated with significant reduction in hematoma expansion and lower in-hospital mortality 4

Discharge Criteria for Negative Initial CT

• Patients with negative initial CT can be safely discharged without repeat imaging or observation if they are neurologically intact, have a Glasgow Coma Scale score of 15, and have no loss of consciousness or post-traumatic amnesia 2
• The risk of delayed intracranial hemorrhage requiring intervention after negative initial CT is extremely low (<1%) in neurologically intact patients 2
• The American College of Emergency Physicians provides Level B evidence that routine repeat imaging is not indicated in patients at baseline neurologic examination with negative initial CT, with a risk of delayed intracranial hemorrhage of 0.6-6% for warfarin and 0.95% for DOACs 4, 3

Observation Protocol for Negative Initial CT

• For patients on warfarin with negative initial CT: 24-hour observation with repeat CT scan before discharge identified one patient in 87 requiring neurosurgical intervention 4
• For patients on NOACs with negative initial CT: out of 178 patients followed for 30 days, only 3 (1.7%) had delayed intracranial hemorrhage, with one death (0.6%) and none required neurosurgical intervention 4
• Consider brief observation (4-6 hours) if age >80 years with loss of consciousness or amnesia 2

Critical Pitfalls to Avoid

• Do not delay reversal while waiting for laboratory confirmation if clinical suspicion is high 1
• Do not assume prophylactic-dose enoxaparin is safe to leave unreversed—check the aPTT and consider reversal if significantly prolonged 1
• Do not routinely discontinue anticoagulation or antiplatelet medications after negative initial CT in neurologically intact patients, as thromboembolic risk may outweigh the small risk of delayed hemorrhage 2
• Be aware of EDTA-dependent pseudothrombocytopenia, which can falsely report low platelet counts and lead to unnecessary platelet transfusions 6

Discharge Instructions and Follow-Up

• Provide clear written discharge instructions including signs of delayed hemorrhage (severe headache, confusion, vomiting, weakness, seizures, worsening drowsiness, slurred speech, vision changes, or inability to wake) and instructions to return immediately or call 911 if symptoms develop 3, 2
• Arrange close observation by a responsible adult who can monitor the patient continuously for the next 24 hours 3
• Arrange outpatient follow-up for reassessment of anticoagulation risk/benefit ratio and fall risk assessment 1, 3, 2

Outcome Considerations

• Oral anticoagulant therapy at the time of presentation with acute subdural hematoma is associated with increased mortality rates and unfavorable outcome at discharge and follow-up 7
• Thrombocyte inhibitor treatment was associated with increased short-term mortality (OR 3.3), whereas vitamin K antagonist treatment was associated with increased long-term mortality (OR 2.7) 7
• Patients on DOACs showed a tendency toward unfavorable outcome, with higher mortality rates than patients on conventional oral anticoagulants 7
• Independent predictors for unfavorable outcome include comatose status 24 hours after surgery (OR 93.2), rebleeding (OR 9.8), respiratory disease (OR 4.1), and infection (OR 11.1) 7