Anaerobic Infections, Central Nervous System

Common cause of brain abscess, subdural empyema, or septic CNS thrombophlebitis

The organisms reach CNS by direct extension from sinusitis, otitis, or mastoiditis or by hematogenous spread from chronic lung infections

Various neurologic deficits

MRI scan (most sensitive) or CT scan

Culture of infected tissue

Antimicrobial therapy is an important adjunct to surgical drainage

• Ceftriaxone, 2 g every 12 hours intravenously, plus metronidazole, 500 mg every 8 hours intravenously

Duration of antibiotic therapy is 6–8 weeks but should be based on follow-up imaging

Some small multiple brain abscesses can be treated with antibiotics alone without surgical drainage