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A. Introductionnavigator

  1. Brain abscess is a local suppurative process in brain parenchyma
  2. ~0.5% of autopsy series
  3. ~1 in 10,000 hospital admissions
  4. Subdural empyema ia a collection of pus between dura and arachnoid membranes

B. Symptomsnavigator

  1. Headache ~65%
  2. Fever 50-60%
  3. Focal Neurologic Signs ~50%
  4. Triad of fever, headache, focal deficit: <50%
  5. Seizures ~35%
  6. Nausea and vomiting: ~30%
  7. Nuchal rigidity ~25%
  8. Papilledema: ~25%

C. Etiologynavigator

  1. Immune status of host is critical determinant
  2. HIV disease leads to distinct causes
  3. In immunocompetent persons, 25-50% are mixed infections
    1. Most commonly Streptococcus intermedius group
    2. Staphylococcus in ~15%
    3. Gram negative aerobic bacilli in 10-20%
    4. Listeria monocytogenes ~10%
    5. Haemophilus species
    6. Nocardia
    7. Acinetobacter
  4. Streptococcal Species
    1. Strep milleri
    2. Strep agninosus
    3. Strep constellatus
    4. Strep intermedius
    5. Anaerobic streptococci (peptostreptococcus, peptococcus, others)
    6. Other streptococci
  5. Anaerobes present in 25-35% of infections

D. Location of Solitary Brain Abscess (Decreasing Frequency)navigator

  1. Frontal ~ Temporal Lobes
  2. Frontoparietal
  3. Parietal
  4. Cerebellar
  5. Occipital

E. Diagnosis navigator

  1. Routine blood and urine studies not usually helpful
  2. Computed tomography or magnetic resonance imaging (MRI, preferred) helpful
  3. Gadolinium enhancement on MRI (ring enhancing lesion) is helpful
  4. Biopsy - stereotactically guided - is required for definitive diagnosis

F. Treatment navigator

  1. Empirical treatment emergently is required to reduce mortality and long-term sequellae
  2. Coverage for mixed flora is strongly advocated
  3. Ampicillin-sulbactam or ticarcillin-clavulanate may be used
  4. Metronidazole can also be used for anaerobic coverage (often with high dose cefotaxime)
  5. Good coverage for gram positives and gram negatives is essential
  6. Oxacillin or vancomycin for staphylococci
  7. Targeted antibiotic therapy may be instituted once confirmed diagnosis is made
  8. CT guided aspiration and drainage is generally recommended
  9. Adjunctive glucocorticoids are often given, but efficacy is unclear
  10. Mortality has been decreasing to <30% [1]

References navigator

  1. Tattevin P, Bruneel F, Clair, et al. 2003. Am J Med. 115(2):143 abstract