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Subdural empyema
Etiology, pathophysiology, clinical presentation, diagnostic approach, and treatment of a bacterial brain abscess, a cranial epidural abscess, and a subdural empyema
Etiology | Pathophysiology | Clinical Presentation | Diagnosis | Treatment | |
|---|---|---|---|---|---|
| Bacterial brain abscess | MCC: streptococci and anaerobes Posttrauma/surgery: Staphylococcus aureus , Enterobacteriaceae, Pseudomonas aeruginosa | Direct spread from contiguous sites (e.g., sinusitis, mastoiditis, otitis media) Hematogenous spread from remote site of infection After cranial trauma/surgery | Fever, headache, focal neurologic deficit, seizures | CT with contrast: hypodense lesion with typically thin ring of contrast enhancement around edge MRI brain with contrast: ring-enhancing lesion | Antimicrobial therapy and, if amenable, aspiration, drainage, or excision |
| Cranial epidural abscess | Similar to brain abscess | Frontal sinus, middle ear, mastoid, orbit infection reaches epidural space through retrograde spread into emissary veins, direct spread of bone infection, or through craniotomy | Hemicranial headache with fever | MRI: crescent-shaped purulent fluid collection seen more prominently on T1 sequence | Immediate neurosurgical drainage, empiric antimicrobial therapy with third- or fourth-generation cephalosporin, metronidazole, and vancomycin for 4-6 weeks after drainage followed by 2-3 months of oral antibiotic |
| Subdural empyema | Aerobic, microaerophilic, and anaerobic streptococci; staphylococci from neurosurgical procedure | Collection of pus between dura and arachnoid, most common predisposing condition is paranasal sinusitis Less common: mastoiditis, neurosurgical procedure | Signs of infection, increased ICP from expanding lesion, stroke, headache, altered mental status, focal deficit | MRI with gadolinium: T1 and FLAIR sequences | Evacuation by drainage or craniotomy, empiric therapy with third- or fourth-generation cephalosporin, metronidazole, vancomycin for 2-3 weeks intravenously then oral antibiotic for 6 weeks |
Sources
MCC , Most common cause; CT , computed tomography; MRI , magnetic resonance imaging; ICP , intracranial pressure; FLAIR , fluid attenuation inversion recovery.
