What are the treatment options for intracranial empyema?

Treatment of Intracranial Empyema

Intracranial empyema requires urgent surgical drainage via craniotomy combined with prolonged intravenous antimicrobial therapy for 6-8 weeks, as medical management alone is inadequate for this neurosurgical emergency. 1, 2, 3

Immediate Surgical Management

Surgical Approach

• Craniotomy is the preferred initial surgical procedure over burr hole drainage, as it provides superior outcomes with lower recurrence rates 2, 4
• Perform bilateral evacuation of subdural spaces when empyema is present, as these infections are frequently bilateral 5
• Immediate reimplantation of the craniotomy bone flap after drainage is safe and effective, with 96.8% long-term viability and low risk of recurrent infection 6
• Endoscopic aspiration may be considered in select cases, though craniotomy remains the gold standard for both decompression and accurate diagnosis 4

Timing and Urgency

• Surgical drainage should be performed as soon as possible after diagnosis, as morbidity and mortality relate directly to delays in treatment 3, 5
• For subdural empyema, this represents an extreme medical and neurosurgical emergency requiring prompt intervention 3
• Approximately 21% of cases require repeat surgical procedures, necessitating close monitoring 1

Antimicrobial Therapy

Empirical Regimen

Initiate triple antimicrobial therapy immediately after diagnosis with:

1. A 3rd-generation cephalosporin (ceftriaxone or cefotaxime) 1, 3
2. Metronidazole for anaerobic coverage 1, 3
3. Nafcillin, oxacillin, or vancomycin for staphylococcal coverage 3, 5

This combination targets the most common pathogens: microaerophilic and anaerobic streptococci (particularly Streptococcus milleri group), Staphylococcus aureus, and gram-negative organisms 3, 5

Duration and Adjustment

• Continue intravenous antimicrobials for 6-8 weeks for aspirated or surgically managed empyemas 1
• Adjust antibiotics based on culture results from surgical drainage; always send specimens for both aerobic and anaerobic culture 3
• Note that no etiological agent is isolated in approximately 56% of cases, making empirical coverage essential 4

Diagnostic Considerations

Imaging

• Brain MRI with diffusion-weighted imaging (DWI), apparent diffusion coefficient (ADC), and T1-weighted sequences with gadolinium is the preferred diagnostic modality 1
• Cerebral arteriography reliably establishes diagnosis and defines location/extent when other modalities are inconclusive 5
• CT scan may miss empyemas detectable by MRI 3

Microbiological Workup

• Obtain blood cultures (positive in approximately 28% of cases) 1
• Send all surgical specimens for aerobic and anaerobic culture 3
• Always submit the abscess wall for histological examination to rule out underlying intracranial tumor, as associated tumors are found in some cases 4

Monitoring and Follow-Up

Surveillance Imaging

• Perform brain imaging immediately if clinical deterioration occurs 1
• Conduct imaging at regular 2-week intervals after surgical drainage until clinical cure is evident 1
• Monitor for complications including seizures, which occur in 32% of patients despite prophylaxis 2

Readmission Risk

• Approximately 14-22% of patients require readmission and repeat craniotomy due to failed resolution 2
• Close follow-up is essential, with mean follow-up duration of at least 43.9 months recommended 6

Critical Pitfalls to Avoid

Diagnostic Delays

• Do not delay imaging in patients with sinusitis, otitis media, or recent neurosurgery who develop headache, fever, altered sensorium, or neurological symptoms 1, 2, 5
• Do not rely on prior antibiotic treatment to exclude empyema, as 33-81% of patients with intracranial complications had received prior antibiotics 1

Lumbar Puncture Hazards

• Avoid lumbar puncture in patients with signs of increased intracranial pressure, as transtentorial herniation can develop within 8 hours in patients with empyema 5
• CSF findings are nonspecific and similar to other CNS infections, providing limited diagnostic value 5

Inadequate Surgical Drainage

• Do not perform burr hole drainage as the primary procedure, as craniotomy is associated with significantly less recurrence 2
• Ensure bilateral exploration when subdural empyema is suspected, as unilateral drainage may miss contralateral collections 5

Prognosis

• Overall mortality ranges from 8-14% despite optimal surgical and medical management 2, 4
• Approximately 45% of survivors experience long-term sequelae at 6 months, including focal neurological deficits and neurocognitive impairment 1
• Rupture of empyema carries substantially increased mortality rates of 27-50% 1