What is the management approach for an acute on chronic subdural hematoma (SDH)?

Management of Acute-on-Chronic Subdural Hematoma

For acute-on-chronic subdural hematoma, immediately discontinue all anticoagulants and antiplatelets for at least 1-2 weeks, rapidly reverse coagulopathy with prothrombin complex concentrate or fresh frozen plasma plus vitamin K, and proceed with urgent surgical evacuation via craniotomy if the hematoma is >10mm thick or causes >5mm midline shift, or if the patient has declining neurological status. 1, 2

Immediate Reversal of Coagulopathy

The acute bleeding component demands urgent action:

• Reverse warfarin immediately with prothrombin complex concentrate (preferred) or fresh frozen plasma plus vitamin K to normalize INR within 15 minutes 1
• Discontinue all anticoagulants and antiplatelet agents for at least 1-2 weeks during the acute period 1
• Administer protamine sulfate if the patient is on heparin, with dosing based on time since last heparin dose 1
• Elevated INR is associated with larger hematoma volumes and worse outcomes, making rapid reversal critical 1

Surgical Indications and Timing

The acute component superimposed on chronic SDH typically requires surgical intervention:

• Perform craniotomy with or without bone flap removal if hematoma thickness >10mm or midline shift >5mm, regardless of Glasgow Coma Scale score 2
• **Evacuate surgically if GCS <9** with declining neurological status (≥2 point GCS drop), asymmetric/fixed pupils, or intracranial pressure >20 mmHg, even if hematoma <10mm 2
• Operate as soon as possible once surgical indications are met - delays worsen outcomes 2
• Single or two burr holes may be effective for the liquefied chronic component, but craniotomy is typically required for the acute clot 3, 2

Medical Management During Acute Phase

• Maintain cerebral perfusion pressure between 60-70 mmHg in the absence of multimodal monitoring 4
• Administer mannitol 20% or hypertonic saline (250 mOsm over 15-20 minutes) for intracranial hypertension 4
• Monitor intracranial pressure in all comatose patients (GCS <9) with acute-on-chronic SDH 2

Post-Operative Management

• Position with head elevated as comfortable 4
• Implement thromboprophylaxis during immobilization, but timing must balance thrombotic versus hemorrhagic risk 4
• The decision to restart anticoagulation depends on thromboembolism risk versus rebleeding risk - for very high thromboembolism risk (mechanical valves), consider restarting warfarin at 7-10 days post-hemorrhage 1
• For lower thromboembolism risk (atrial fibrillation without prior stroke), antiplatelet agents may be considered instead of full anticoagulation 1

Key Clinical Pitfalls

• Alcoholism with repeated trauma is a prominent risk factor for acute-on-chronic SDH - these patients warrant heightened surveillance 3
• Acute-on-chronic SDH appears on CT as hyperdense clot with irregular blurred margins or lumps within liquefied hematoma - this mixed-density pattern is the radiographic hallmark 3
• This entity represents approximately 8% of chronic SDH cases, making it more common than often recognized 3
• Hemorrhagic transformation within ischemic stroke has different management - anticoagulation may be continued if asymptomatic and the indication is compelling 1

Follow-Up Monitoring

• Advise patients to seek urgent care for new severe headache, neurological deficits, or altered mental status 4
• Recurrent SDH is the most common cause of readmission (33% of readmissions) after chronic SDH surgery 5
• Hypertension and abnormal INR are significant predictors of readmission after chronic SDH evacuation 5