Meningitis & Encephalitis

• When meningitis is suspected → blood cultures + ceftriaxone 2 g q12h + vancomycin NOW; never let LP delay antibiotics.
• Age >50 or immunocompromise calls for added ampicillin (Listeria); dexamethasone 10 mg q6h goes with or before the first antibiotic dose (pneumococcal).
• Fever with focal signs or seizures is HSV encephalitis until excluded: start aciclovir 10 mg/kg q8h and send LP HSV PCR.
• Brain abscess: MRI, neurosurgery, ceftriaxone/metronidazole (dental source); don't LP with mass effect.

Meningitis

First tests: Blood cultures, Full blood count, Sodium, potassium, bicarbonate, urea and creatinine, Blood glucose.

Only if indicated: Lumbar puncture and CSF studies, Noncontrast CT head, HIV testing.

Repeat monitoring: Neurological and systemic reassessment.

Encephalitis

First tests: Blood glucose, Sodium, potassium, bicarbonate, urea and creatinine, MRI brain.

Only if indicated: Lumbar puncture and CSF studies, EEG, Autoimmune encephalitis studies.

Repeat monitoring: Serial neurological assessment.

• Initial Evaluation of Possible Central Nervous System (CNS) Infection