Diagnosis
Infection in the subdural space, often present like bacterial meningitis. It can be missed on CT, especially unenhanced, so best test is an MRI as it is often just a thin rim of pus between the brain and the skull.
The most common triad of symptoms are fever, headache, and vomiting but are often nonspecific.
Epidemiologic Risks
Microbiology
Otitis and sinusitis source: Often polymicrobial with streptococci, anaerobes, S. aureus and/or aerobic gram-negative bacilli.
Postoperative source: S. aureus, gram-negative rods like Pseudomonas aeruginosa, and Propionibacterium acnes (especially years after the surgery).
Empiric Therapy
Drain drain drain, it is an emergency.
Sinusitis/Otitis: vancomycin PLUS a third-generation cephalosporin PLUS metronidazole OR carbapenems PLUS vancomycin.
Post-op/trauma: vancomycin PLUS a third-generation cephalosporin (especially ceftazidime or cefepime) OR carbapenems PLUS vancomycin.
Pearls
I would avoid the penicillin/beta-lactamase inhibitors as they do not cross the blood-brain barrier well.
Rants
Last Update: 02/26/19.