Meningitis

History

  • Headache (onset, location, duration, severity, characteristics, alleviating/aggravating factors, radiation, symptoms associated – N/V, fever, neck stiffness, seizures, altered sensorium, photophobia, lethargy, poor feeding)
  • Previous URTI, otitis media, sinusitis, odontogenic
  • Previous neurosurgical procedures, penetrating head trauma
  • Infectious contacts
  • Immunocompromised states (cancer, EtOH, etc)

Physical exam

  • ABCs
  • Head and neck (neuro)
    • Neck – nuchal rigidity, lymphadenopathy
    • Look for focal neurologic signs (full neurological exam): CN (3,4,6,7 primarily affected), motor, sensory, reflexes, coordination
    • Eyes – papilledema
    • Ears – otitis media
  • Dermatological: look for nonblanching petechiae and cutaneous hemorrhages
  • Special signs
    • Kernig’s sign: with hip at 90O, patient will resist passive knee extension
    • Brudzinski’s sign: with passive neck flexion, patient will flex both hips

Differential diagnosis

  • Fever with neurological findings
    • Brain Abscess
    • Encephalitis (i.e. HSV)
    • Pediatric febrile seizures
  • Seizures
    • Delirium Tremens
    • Pediatrics, Febrile Seizures
  • Intracranial pathology
    • Neoplasm
    • Subarachnoid Hemorrhage



 

Etiology

  • Bacterial
    • Neonates: Listeria, E.coli, GBS
    • Pediatrics: H.influenza, S.pneumoniae, N.meningitidis
    • Adolescents/Adults: S.pneumoniae, N.meningitidis
    • Elderly: S.pneumoniae, N.meningitidis, Listeria
    • Immunocompromised: Listeria
  • Viral: Enterovirus, HIV, HSV-2, West Nile
  • Fungal: Cryptococcus, Coccidioidomycosis
  • Other: TB, Borrelia (Lyme), Treponema pallidum (neurosyphilis)

Investigations

  • Bloodwork: CBCD, electrolytes
  • CT head: R/O differential diagnosis, R/O increased ICP
  • LP (gram stain, C&S, cell count, glucose, protein, PCR +/- serology)
Bacterial Viral
Appearance (clear) May be cloudy May be cloudy
Opening pressure (5-15 cmH2O) Increased Normal or slightly increased
Glucose ratio (CSF:plasma >0.5) <0.3 Normal
Protein (45-60 mg/dL) 100-500 Normal
WBC (<5) Thousands Hundreds
Predominant WBC Neutrophils Lymphocytes

Treatment

  • Initiate treatment empirically if you suspect meningitis
  • Neonates
    • Ampicillin (age 0-7 d: 50 mg/kg IV q8h; age 8-30 d: 50-100 mg/kg IV q6h)
    • Cefotaxime 50 mg/kg IV q6h
  • Infants, children, adults
    • Ampicillin
    • 3rd generation cephalosporin
    • Vancomycin
  • Adjust antibiotics when gram stain and C&S results come back
  • If CSF is cloudy, + gram stain or leukocytes >1000
    • Dexamethasone 10 mg q6h X 4 days
    • First dose given 20 minutes prior to, or with first dose of antibiotics
    • Associated with better outcomes and lower mortality

Prevention

  • Immunization
    • Pediatrics – Pentacel (H.influenza), Prevnar (S.pneumoniae), Menjugate (N.meningitidis)
    • Adults – Pneumovax (pneumococcus)
    • Immunocrompromised (asplenia, HIV) – Menjugate (meningococcus)
    • Prophylactic treatment in close contacts

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