Brain abscess

[Clin Microbiol Infect 2023;1-71]


- Symptoms:  headache, fever, focal neurologic deficit, seizures, mental status changes.

- Predisposing conditions:

  • contiguous:  otitis, mastoiditis, sinusitis, recent neurosurgery, recent cranial trauma
  • hematogenous:  endocarditis, pulmonary circulation shunts, hereditary hemorrhagic telangiectasia, dental infection

- Investigations:

  • MRI preferred; alternative CT with contrast
  • Blood cultures – positive in 28% of cases
  • HIV testing recommended for all patients with brain abscess, especially if bilateral
  • Stereotactic aspiration recommended for:
    • all abscesses ≥ 2.5 cm
    • periventricular abscess
    • at least one accessible abscess ≥ 1 cm

         NB: Aspiration not required for toxoplasmosis in seropositive patients with HIV and ring-enhancing brain lesions.

         Send for aerobic & anaerobic culture and for histopathological analysis. 

         Depending on epidemiology, also consider TB.

         Molecular diagnostics recommended if culture negative.


- Treatment – Empiric anaerobic coverage recommended unless secondary to endocarditis and organism is known. Continue anaerobic coverage if an oral organism is isolated on culture.