What is the treatment for brain abscess?

Treatment of Brain Abscess

Brain abscess requires immediate neurosurgical aspiration or excision combined with 6-8 weeks of intravenous antibiotics (third-generation cephalosporin plus metronidazole for community-acquired cases), with surgery performed as soon as possible for all abscesses ≥2.5 cm or those causing significant mass effect. 1, 2

Diagnostic Imaging Before Treatment

• Brain MRI with diffusion-weighted imaging (DWI)/apparent diffusion coefficient (ADC) and T1-weighted sequences with and without gadolinium is the preferred imaging modality for confirming diagnosis and surgical planning 1, 2
• If MRI is unavailable, contrast-enhanced CT is an acceptable alternative 1, 2
• Withhold antimicrobials until aspiration or excision in stable patients without sepsis, impending rupture, or herniation if neurosurgery can be performed within 24 hours to maximize culture yield 1, 2

Neurosurgical Management

Surgical intervention is the cornerstone of treatment and should be performed as soon as possible in all patients whenever feasible (excluding toxoplasmosis). 1, 2

Indications for immediate surgery:

• All abscesses ≥2.5 cm in diameter (reduces mortality from 24% to 9%) 3, 4
• Abscesses in critical locations causing mass effect regardless of size 3
• Abscesses with close proximity to ventricles (high rupture risk with 27-50% mortality) 3
• Clinical deterioration despite medical therapy 3, 5

Surgical technique selection:

• Aspiration is the preferred neurosurgical procedure in most cases 3
• Excision should be considered for superficial abscesses in non-eloquent areas, posterior fossa location, or difficult-to-treat pathogens 3
• Stereotactic-guided minimally invasive techniques enable access to deep-seated abscesses 3
• Approximately 21% of aspiration cases require repeat procedures versus 6% for excision 3

Repeat intervention criteria:

• Clinical deterioration occurs 3
• Abscess enlarges on imaging 3
• No reduction in abscess volume by 4 weeks after initial aspiration 3

Antimicrobial Therapy

Empirical regimens (start immediately after surgical drainage):

Community-acquired brain abscess (immunocompetent):

• Third-generation cephalosporin (ceftriaxone or cefotaxime) PLUS metronidazole 1, 2, 6

Post-neurosurgical brain abscess:

• Carbapenem PLUS vancomycin or linezolid 2

Severely immunocompromised patients (transplant recipients):

• Third-generation cephalosporin PLUS metronidazole PLUS trimethoprim-sulfamethoxazole PLUS voriconazole 2, 6

Duration of therapy:

• 6-8 weeks of intravenous antimicrobials for aspirated or conservatively treated abscesses 1, 2
• 4 weeks may be considered for completely excised abscesses 1, 2
• Adjust antibiotics based on culture results and sensitivities from aspirated pus 7

Adjunctive Medical Management

Corticosteroids:

• Dexamethasone is strongly recommended for severe symptoms from perifocal edema or impending herniation 1, 2
• Reduce dose as soon as intracranial pressure improves, as steroids may retard abscess capsule formation and decrease antibiotic penetration 7

Antiepileptic prophylaxis:

• Primary prophylaxis with antiepileptic drugs is NOT routinely recommended 1, 2
• Exception: Frontal lobe abscesses carry increased epilepsy risk and may warrant consideration 3

Monitoring and Follow-Up

• Perform brain imaging every 2 weeks after aspiration or excision until clinical cure is evident 3
• Obtain immediate imaging if clinical deterioration occurs 3
• Residual contrast enhancement may persist for 3-6 months after clinical cure—do not prolong antimicrobials based solely on radiological findings after clinical improvement 3

Critical Pitfalls to Avoid

• Rupture occurs in 10-35% of cases with 27-50% mortality—intervene surgically early for abscesses near ventricles regardless of size 3
• Do not delay surgery for abscesses ≥2.5 cm to attempt medical management alone, as this increases mortality from 9% to 24% 3, 4
• Send abscess pus for both routine cultures AND molecular-based diagnostics if available, especially when cultures are negative 1, 2
• Obtain blood cultures (positive in 28% of cases) and consider HIV testing in all non-traumatic brain abscess patients 3

Long-Term Outcomes

• Approximately 45% of survivors experience long-term sequelae at 6 months, including focal neurological deficits and neurocognitive impairment 3
• Referral to specialized neurorehabilitation is vital for managing sequelae 3
• Brain abscess is associated with substantially increased 1-year mortality and increased cancer risk, necessitating low threshold for diagnostic workup 3