Antibiotics for brain abscess
Vancomycin: covers MRSA.15 mg/kg IV q8-12 hours to achieve through 15-20 mg/dl.
3rd generation cephalosporin (ceftriaxone); utilize cefepime if post surgical
The clinical effectiveness of tertiary-generation cephalosporin+vancomycin+metronidazole for bacterial brain abscess was 88%. Therefore, combined antibiotics in cases with no evidence of positive culture in brain abscess are strongly recommended 1).
If culture shows only Streptococcus: Penicillin alone or with ceftriaxone.
If culture shows Methicillin sensitive Staphylococcus aureus and the patient has not beta lactam allergy, can change vancomycin to nafcillin.
Cryptococcus neoformans, Aspergillus sp., Candida sp.: Liposomal Amphotericin B 3-4 mg/kg IV daily + Flucytosine 25 mg/kg PO QID.
In AIDS patients: Toxoplasma gondii is a common pathogen, and initial empiric treatment with sulfadiazine + pyrimethamine + leucovorin is often used.
Antimicrobial treatment for a brain abscess is generally long (6-8 wk) because of the prolonged time needed for brain tissue to repair and close abscess space. The United Kingdom treatment guidelines advocate 4-6 weeks if the abscess has been drained or removed and 6-8 weeks if drainage occurred 2).
The duration of therapy can be adjusted according to the patient’s condition, causative organism(s), number of abscesses and their size, and response to treatment. A shorter course (4-6 wk) may suffice for cerebritis and in patients who underwent surgical drainage 3).
A long course (>6 wk) is required for necrotic and/or encapsulated abscess with tissue necrosis, multiloculated abscess, abscesses in vital intracranial locations (ie, brain steam), and in immunocompromise.
The length of therapy is guided by continuous assessment of the clinical course and followup imaging studies. The antimicrobial therapy is continued until a clinical response occurs and CT or MRI findings show resolution. However, because the abscess site may show persistent enhancement for several months. This finding alone is not an indication to continue antimicrobial therapy or for surgical drainage 4).