What is the management plan for a patient diagnosed with a subacute subdural hematoma?

Management of Subacute Subdural Hematoma

For subacute subdural hematoma, burr hole drainage is the preferred surgical approach when intervention is needed, though stable patients without significant neurological deficits can be managed conservatively with close monitoring and serial imaging. 1

Initial Assessment and Risk Stratification

The first step is determining whether surgical intervention is needed based on:

• Glasgow Coma Scale (GCS) score - assess level of consciousness 1, 2
• Pupillary examination - abnormal pupils indicate herniation risk 3
• Focal neurological deficits - document any motor or sensory changes 1
• CT imaging characteristics - measure maximal hematoma thickness and degree of midline shift 1
• Symptom progression - evaluate for headache, altered consciousness, or vomiting 1

Surgical Indications

Immediate surgical evacuation is indicated for:

• Symptomatic subdural hematoma with significant mass effect 1
• Neurological deterioration or decreased level of consciousness 1, 2
• Hematoma thickness >5 mm with midline shift >5 mm 2

Burr hole drainage is the preferred first-line surgical approach for subacute subdural hematomas, with subdural drain placement to reduce recurrence rates 1. This is advantageous because it is minimally invasive and can be performed with smaller incisions, shorter operative time, and decreased anesthesia duration compared to craniotomy 4.

A critical pitfall: Do not delay surgical intervention when neurological deterioration occurs, as this leads to poorer outcomes 1, 2. However, research shows that in elderly patients with good neurologic exams who can be closely monitored, delayed intervention (median 11 days) allowing the hematoma to become more chronic is safe and permits smaller surgery 4.

Conservative Management Protocol

Conservative management with close monitoring is appropriate for stable patients without significant neurological deficits 1, 2. This requires:

• Regular neurological assessments - monitor GCS, pupils, and focal deficits serially 1
• Maintain euvolemia - avoid both hypovolemia and hypervolemia 1
• Serial imaging - repeat CT scans to monitor for progression 1

The rationale: spontaneous resolution of subdural hematomas can occur, though it is rare 5. Small hematomas without mass effect can be observed, particularly in elderly patients where close neuromonitoring allows for delayed intervention if needed 4.

Airway and Hemodynamic Management

If the patient requires surgical intervention or has decreased consciousness:

• Secure the airway immediately with tracheal intubation and mechanical ventilation 2
• Monitor end-tidal CO₂ continuously to maintain PaCO₂ within normal range - hypocapnia causes cerebral vasoconstriction and brain ischemia 2
• Maintain systolic blood pressure >110 mmHg using vasopressors (phenylephrine or norepinephrine) - even a single episode of hypotension (SBP <90 mmHg) significantly worsens outcomes 2
• Use continuous infusions of sedatives rather than boluses to prevent hemodynamic instability 2

Anticoagulation Management

If the patient is on anticoagulation:

• Rapidly reverse anticoagulation using prothrombin complex concentrate plus vitamin K 1
• Interrupt anticoagulation for 7-15 days - the risk of ischemic events during this period is low 1
• Restart anticoagulation approximately 4 weeks after surgical removal if no ongoing fall risk or alcohol abuse is present 1

Post-Operative Monitoring

After surgical evacuation:

• Monitor intracranial pressure (ICP) if any of the following are present: preoperative GCS motor response ≤5, preoperative anisocoria or bilateral mydriasis, preoperative hemodynamic instability, intraoperative cerebral edema, or postoperative new intracranial lesions 2
• Maintain cerebral perfusion pressure (CPP) between 60-70 mmHg - CPP <60 mmHg is associated with poor outcomes 2
• Antiepileptic drugs are NOT recommended for primary prevention of post-traumatic seizures, as they show no benefit and may worsen neurological outcomes 1

Special Considerations

In elderly patients (≥65 years): Small hematomas can expand rapidly, especially in those on anticoagulants, requiring careful monitoring 2. However, delayed surgical intervention (allowing conversion to chronic subdural hematoma) is safe in stable patients with good neurologic exams and permits less invasive surgery 4.

MRI findings in subacute subdural hematoma: Diffusion-weighted MRI may demonstrate a two-layered hematoma structure, and FLAIR imaging may show irregularly shaped hematoma with gyrus patterns 6. These findings can help predict whether burr-hole surgery will be sufficient or if a small craniotomy should be considered 6.