What is the recommended evaluation and management for an acute subdural hematoma in an older patient on anticoagulation?

Management of Acute Subdural Hematoma in Older Anticoagulated Patients

Immediate Reversal of Anticoagulation

Rapidly reverse anticoagulation using prothrombin complex concentrate (PCC) plus vitamin K for warfarin, or specific reversal agents for DOACs, before any surgical intervention. 1

• Administer 4-factor PCC at 25-50 IU/kg PLUS 5-10 mg intravenous vitamin K immediately for warfarin reversal, targeting INR <1.5 before surgery 2, 3
• For dabigatran: give idarucizumab 5 g IV immediately 2, 3
• For rivaroxaban or apixaban: administer andexanet alfa (400 mg IV bolus over 15 min followed by 480 mg infusion over 2 hours for low dose; 800 mg over 30 min followed by 960 mg over 2 hours for high dose) 2
• Target PT/aPTT < 1.5 times normal control and platelet count > 50,000/mm³ before any neurosurgical procedure 1

Mandatory Imaging and Assessment

• Obtain non-contrast head CT within 3 hours of presentation; 28-38% of patients show hematoma expansion on subsequent imaging 1, 2
• Document Glasgow Coma Scale (GCS) with individual components (Eye, Motor, Verbal) and pupillary examination (size and reactivity) 1, 2, 3
• Consider CT angiography to identify contrast extravasation, which predicts high risk for hematoma expansion 1

Surgical Indications—Act Immediately

Perform immediate surgical evacuation when any of the following criteria are met:

• Subdural hematoma thickness >10 mm 2, 3
• Midline shift >5 mm 1, 2, 3
• GCS decline of ≥2 points 1, 2, 3
• Development of anisocoria, bilateral mydriasis, or posturing indicating herniation 1, 2, 3
• Development of focal neurological deficits indicating mass effect 2, 3
• Any neurological deterioration or decreased level of consciousness 1

Do not delay surgery for "medical optimization" beyond basic resuscitation and coagulation reversal—delaying worsens prognosis. 1

Conservative Management—When Appropriate

For small hematomas (<10 mm thickness, <5 mm midline shift) in neurologically stable patients (GCS 14-15) without focal deficits, conservative management with close monitoring is acceptable 1, 4:

• Mandatory admission regardless of normal neurological examination—delayed deterioration can occur even in stable patients 2, 3
• Monitor GCS every 15 minutes for 2 hours, then hourly for 12 hours 3
• Perform serial neurological examinations for 24-72 hours 3
• Obtain repeat CT at 20-24 hours to assess for progression 1
• Maintain mean arterial pressure ≥80 mmHg to ensure adequate cerebral perfusion 2, 3

Important caveat: Even small hematomas can progress to chronic subdural hematoma requiring delayed surgery in approximately 6% of conservatively managed cases 4. Older patients with brain atrophy have more potential space to accommodate larger hematomas before symptoms develop 5.

Hemodynamic Management During Acute Phase

• Maintain systolic blood pressure >100 mmHg or MAP >80 mmHg 1, 2, 3
• Target cerebral perfusion pressure ≥60 mmHg (ideally 60-70 mmHg) when ICP monitoring is in place 1
• Maintain PaO₂ 60-100 mmHg and PaCO₂ 35-40 mmHg 1
• Avoid hypotension—elderly patients may have blunted catecholamine responses and cannot mount appropriate tachycardic response 2

Temporary Bridge Therapies (Only While Preparing for Surgery)

If impending herniation occurs before surgical evacuation:

• Administer mannitol as a temporary bridge only—not sufficient as standalone treatment 1
• Use hyperventilation targeting PaCO₂ 35-40 mmHg solely as a short-term measure 1
• Do not rely on these as definitive therapies—they serve only to buy time until craniotomy 1

Postoperative Management

• Delay VTE prophylaxis for 24 hours after surgery 2, 3
• Initiate prophylaxis only when repeat CT shows no hemorrhage progression 2, 3
• Use LMWH 30 mg every 12 hours (adjust for anti-Xa levels and weight) 2
• Do not routinely use antiepileptic drugs for primary prevention—they show no benefit and may worsen outcomes 1

Restarting Anticoagulation

• Restart anticoagulation approximately 4 weeks after surgical removal if no ongoing fall risk or alcohol abuse is present 1
• The duration of anticoagulation interruption is typically 7-15 days for non-surgical cases, with low risk of ischemic events during this period 1

Critical Pitfalls to Avoid

• Never discharge patients with documented subdural hematomas based solely on normal examination—delayed deterioration can occur 2, 3
• Never administer long-acting sedatives or paralytics before neurosurgical evaluation—this masks clinical deterioration 2
• Never delay surgical intervention when neurological deterioration occurs—this leads to poorer outcomes 1
• Do not assume minor symptoms are benign without neuroimaging in elderly anticoagulated patients 3

Evidence Regarding Anticoagulation and Outcomes

Contrary to common assumptions, patients on oral anticoagulants who receive appropriate medical reversal agents early do quite well, and no significant impact on eventual outcome has been demonstrated when reversal is prompt 5. The initial volume, size, and GCS score are more predictive of need for surgery than age or anticoagulation status alone 5.

The often-cited concern about falls is overstated: A patient would have to fall 295 times for the risk of subdural hematoma to outweigh the benefit of anticoagulation with warfarin (even higher for DOACs), and frailty per se should not be an exclusion criterion for anticoagulation 6.