Brain abscess:
- The etiology of brain abscess is based on the underlying predisposing factor and is listed in Table 8.5 along with the choice of empiric therapy.
- An attempt should be made to establish the etiology by blood cultures and aspiration of pus. This is especially required if the host is immunocompromised. Imaging of the chest and abdomen should be done to see if an extra-CNS site can be sampled.
- Drainage by aspiration is important for large abscesses/ drug resistant organisms. Primary excision can also be attempted. Treatment should be modified as per cultures and should be given for at least 4-6 weeks and till radiologic stabilization. Medical treatment is significantly shortened if abscess drainage is performed and can be even 3 weeks where excision of the abscess is done.
Etiology and empiric therapy for brain abscess
Predisposing factor |
Likely etiology |
Empiric therapy |
|---|---|---|
| Hematogenous spread from cyanotic congenital heart disease/ lung infections/ endocarditis | Aerobic/ microaerophilic Streptococci, S. aureus | Cefriaxone and metronidazole with/ without vancomycin |
| Contiguous spread from otitis media/mastoiditis/sinusitis/ dental infection | Aerobic, microaerophilic, anaerobic streptococci, Anaerobic gram negative bacilli, S. aureus, Pseudomonas | Ceftriaxone and metronidazole |
| HIV | Mycobacterium tuberculosis, Nocardia, Toxoplasma, Cryptococcus, Listeria | No empiric therapy |
| Immunocompromised | Nocardia, Mycobacterium, Toxoplasma, Mucorales, Aspergillus, Listeria, Cryptococcus, Candida | |
| Neonates | Citrobacter/ Enterobacteriaceae, Candida | Meropenem |