Brain (CNS)
Bacterial Meningitis
세균성수막염
Acute purulent infection of leptomeninges; medical emergency
- How common
- ~4-6 per 100,000/yr
- Typical age
- Infants, adolescents, elderly
What is it?
Nasopharyngeal/middle ear colonization → hematogenous or direct spread → subarachnoid infection → cytokine storm → BBB breakdown and edema.
Commonly affected: Leptomeninges, CSF, superficial cortex
How it develops
- ColonizationS. pneumoniae, N. meningitidis, H. influenzae
- Hematogenous invasionBacteremia → crosses BBB
- Subarachnoid inflammationNeutrophil infiltrate, cytokines
- Cerebral edema/raised ICPBBB damage, vasogenic and cytotoxic
Symptoms
- High fever/chillsSudden onset
- Severe headacheDiffuse, throbbing
- Neck stiffnessPositive Kernig/Brudzinski
- Altered LOC/seizureWith progression
- Petechial rash (meningococcal)Non-blanching, sepsis warning
How it is examined
- Meningeal signsKernig (knee resistance), Brudzinski (hip flexion)
- Fundoscopy/focal deficitsAssess raised ICP/herniation risk
- Skin rashLook for meningococcal petechiae
Imaging
Head CT before LP if immunocompromised, focal deficit, seizure, papilledema.
- Cerebral edema
- Rule out mass effect
MRI with contrast shows leptomeningeal enhancement.
- Leptomeningeal enhancement
- Ventriculitis
- Abscess complications
Non-surgical care
- Empiric antibiotics within 1 hVancomycin + ceftriaxone (ages 2-50)
- Add ampicillin (>50, infants)For Listeria coverage
- Dexamethasone 0.15 mg/kg q6hBefore/with antibiotics; reduces pneumococcal mortality
- Lumbar punctureBefore antibiotics if safe
- Contact prophylaxisRifampin/ciprofloxacin (meningococcal)
Conservative options are generally tried first. Medications listed here can have side effects — discuss them with your prescriber.
When surgery is considered
Hydrocephalus, abscess, or ventriculitis
Procedures that may be discussed
- EVD
- V-P shunt for chronic hydrocephalus
- Abscess drainage
Outlook
Treated mortality 10-25%; neurologic sequelae in ~30%. Speed of antibiotics is critical.