Synopsis
Recognise focal intracranial suppuration, obtain urgent contrast imaging and blood cultures, coordinate neurosurgical aspiration for microbiology and pressure control, and deliver source-directed prolonged antimicrobial treatment.
- Brain abscess presents with headache, focal neurology, seizure, cognitive change or raised pressure; fever and the full triad are often absent.
- Do not perform lumbar puncture because a focal mass and pressure gradient can precipitate herniation and CSF rarely identifies the organism.
- Use contrast MRI as the most sensitive imaging test; CT is appropriate immediately when MRI is unavailable or the patient is unstable.
Key red flags
Falling consciousness, abnormal pupils or Cushing physiology indicates impending herniation and requires emergency neurosurgical management.
Progressive headache, focal weakness, dysphasia, field loss, personality change or seizure suggests a focal cerebral lesion requiring urgent imaging.
Investigation priorities
Define abscess number, location, diffusion restriction, oedema and ventricular involvement.
Management branches
A focal neurological infection or intracranial mass is suspected.
- Use ABCDE, neurological observations and seizure treatment and obtain urgent contrast imaging without lumbar puncture.
- Take blood cultures and involve neurosurgery and infection specialists immediately; start empirical therapy before aspiration when unstable.
Key medicines
Ceftriaxone and metronidazole empirical regimenGive ceftriaxone 2 g intravenously every 12 hours plus metronidazole 500 mg intravenously or orally every 8 hours for a community-acquired oral, sinus or ear pattern.
Vancomycin resistant-staphylococcal componentAdd intravenous vancomycin using local weight, renal and concentration-guided dosing after neurosurgery, trauma or MRSA risk.