Management of Acute on Chronic Subdural Hematoma
Acute on chronic subdural hematoma requires urgent surgical evacuation when there is significant mass effect, with craniotomy or craniectomy being the preferred surgical approach over burr holes. 1
Initial Assessment and Management
Immediate Evaluation
- Perform CT head without contrast to assess:
- Hematoma thickness (critical threshold: >10 mm)
- Midline shift (critical threshold: >5 mm)
- Mass effect on brain structures
- Presence of mixed density (acute on chronic) blood products 1
Medical Stabilization
- Maintain target parameters:
- Intracranial pressure (ICP) <22 mmHg
- Cerebral perfusion pressure (CPP) >60 mmHg
- Mean arterial pressure (MAP) 80-110 mmHg
- PaO2 >60 mmHg 2
Coagulopathy Management
- Immediately reverse anticoagulation/antiplatelet medications if surgical intervention is anticipated 2
- Check PT, PTT, INR, and platelet count
- Administer appropriate reversal agents based on the specific anticoagulant/antiplatelet medication
Surgical Management
Indications for Urgent Surgical Evacuation
- Hematoma thickness >10 mm
- Midline shift >5 mm
- Neurological deterioration
- Significant mass effect regardless of neurological status 1
Surgical Approach
- Craniotomy or craniectomy is preferred for acute on chronic SDH (rather than burr holes used for chronic SDH) 1
- Intraoperative subdural drain placement significantly reduces recurrence risk and improves functional outcomes 3
Post-Operative Care
- ICU monitoring with:
- Serial neurological examinations
- Monitoring for pneumocephalus resolution
- Management of intracranial pressure
- Early drain removal when drainage becomes minimal 1
Specific Medical Management
Seizure Management
- Administer prophylactic anti-seizure medications, especially in high-risk patients 2, 4
- Monitor for clinical and subclinical seizure activity
Respiratory Management
- Maintain oxygenation (PaO₂ ≥97.5 mmHg)
- Control ventilation with normoventilation (PaCO₂ 34-38 mmHg)
- Use low tidal volume ventilation (6 ml/kg) with moderate PEEP
- Avoid hyperventilation unless signs of imminent cerebral herniation are present 5
Blood Pressure Management
- Maintain systolic blood pressure >110 mmHg
- Use vasopressors (phenylephrine, norepinephrine) if needed to rapidly correct hypotension 5
- Avoid hypertension (systolic >160 mmHg) 6
Post-Operative Mobilization
- Early mobilization is recommended - enforced bed rest has been associated with unfavorable outcomes 3
- Head elevation at 20-30° to improve jugular venous outflow and lower ICP 5
Special Considerations
Pediatric Patients
- Acute subdural hematoma with mass effect is considered a time-critical condition requiring urgent transfer to a neurosurgical center 6
- Transfer should be expedited with appropriate stabilization and management of intracranial pressure 6
Monitoring and Follow-up
- Regular neurological assessments to track recovery and detect complications
- Follow-up imaging to assess for reaccumulation, which occurs in approximately 9% of cases 3
- Consider transcranial Doppler as part of assessment (poor prognosis indicators: diastolic flow velocity <20 cm/s and pulsatility index >1.4) 5
Pitfalls and Caveats
- Significant variation exists in surgical management between centers - the proportion of patients with acute subdural hematoma undergoing surgery ranges from 7% to 52% between centers 6
- The type of surgery varies considerably - primary decompressive craniectomies (vs. craniotomies) range from 6% to 67% between centers 6
- Failure to place a subdural drain intraoperatively independently predicts recurrence and unfavorable functional outcomes 3
- Increasing patient age, postoperative bed rest, and use of a single burr hole (for chronic SDH) independently predict unfavorable outcomes 3