143.1 🎓 醫孞生版

143.1.0.1 📌 䞀頁重點

  • 䞉聯埵: fever + headache + neck stiffness (~ 50% only have all 3)
  • Bacterial 病原 by age:
    • Neonate: GBS, E. coli, Listeria
    • 1 mo - 2 yr: S. pneumoniae, N. meningitidis, Hib (vaccine reduced)
    • 2-50 yr: S. pneumoniae, N. meningitidis
    • > 50 / immunocompromised / alcoholic: + Listeria
    • HCAI / neurosurgery / shunts: Staph, GN, Pseudomonas, anaerobes
  • Empirical Bacterial (< 1 hr!):
    • < 50 yr: Ceftriaxone 2g IV q12h + Vancomycin 15-20 mg/kg q8-12h + Dexamethasone 10 mg q6h (just before/with first dose)
    • ≥ 50 yr / immunocompromised: + Ampicillin 2g IV q4h (Listeria)
    • HCAI: Vanc + Cefepime/Meropenem
  • Viral meningitis: lymphocytic CSF + normal glucose; supportive (HSV PCR rule out)

143.1.0.2 1⃣ Diagnosis

143.1.0.2.1 Clinical Signs
  • Triad: fever, headache, neck stiffness (only 50%)
  • + Altered mental status (Bickerstaff: fever + neck stiffness + altered = bacterial more likely)
  • Kernig sign, Brudzinski sign (low sensitivity)
  • Photophobia, vomiting
  • Skin: petechiae (meningococcus!), rash, conjunctivitis
143.1.0.2.2 LP
  • Do ASAP (after CT if focal deficit, immunocompromised, papilledema, age > 60, history seizure)
  • Don’t delay antibiotic for LP / CT
143.1.0.2.3 CSF Findings
Type Opening pressure WBC PMN% Protein Glucose (CSF:serum) Lactate
Normal 5-20 cm H2O < 5 < 20% < 45 > 0.6 < 2 mmol/L
Bacterial ↑↑ (>25) 100-10K > 80% ↑↑ > 100-500 ↓↓ < 0.4 > 4
Viral Normal-mild ↑ 10-1000 < 50% (early may be PMN) Normal-mild ↑ Normal < 2
TB / Fungal ↑ 50-1000 lymphocytic < 50% ↑↑ Low High
Aseptic (post-infection) Normal 10-100 < 50% Mild ↑ Normal Normal
143.1.0.2.4 Microbiology
  • Gram stain (positive 60-80% in bacterial)
  • Culture (positive 70-85%)
  • PCR multiplex (FilmArray ME): S. pneumo, N. meningitidis, HIB, Listeria, E. coli, GBS, HSV-1/2, VZV, enterovirus, parechovirus, HHV-6, Cryptococcus, etc.
  • India ink + Cryptococcal antigen (if immunocompromised)
  • AFB + GeneXpert MTB (if TB risk)
143.1.0.2.5 Bloods
  • Blood culture × 2 sets (before antibiotic if possible — but don’t delay for it)
  • CBC, CRP, lactate, glucose
  • Procalcitonin (helpful for bacterial vs viral)

143.1.0.3 2⃣ Empirical Treatment (CRITICAL — < 1 hr)

Age / Group Empirical
< 50 yr (community) Ceftriaxone 2g IV q12h + Vancomycin 15-20 mg/kg q8-12h + Dexamethasone 10 mg IV q6h × 4d (immediately before/with 1st antibiotic)
≥ 50 yr OR immunocompromised OR alcoholic + Ampicillin 2g IV q4h (Listeria)
HCAI / neurosurgery / shunt Vancomycin + Cefepime OR Meropenem (cover staph + Pseudomonas + GN)
Severe penicillin allergy Vancomycin + Aztreonam + Bactrim (Listeria)
143.1.0.3.1 Dexamethasone
  • S. pneumo, Hib meningitis: dexamethasone reduces mortality + neurologic sequelae (especially deafness in children)
  • N. meningitidis: no proven benefit but not harmful
  • TB meningitis: dexamethasone × 6-8 wks (Thwaites trial)
  • Should be given before/with first antibiotic (corticosteroids reduce inflammation surge from lysis)
143.1.0.3.2 Targeted Therapy (after culture)
Organism Treatment Duration
S. pneumoniae (PCN-sensitive) Penicillin G OR Ceftriaxone 10-14 days
S. pneumoniae (PCN-resistant) Vancomycin + Ceftriaxone 14 days
N. meningitidis Penicillin G OR Ceftriaxone 7 days
Hib Ceftriaxone 7-10 days
Listeria Ampicillin + Gentamicin 3 weeks
GBS Penicillin G OR Ampicillin 14-21 d
E. coli / GN Ceftriaxone or Meropenem (if ESBL) 21 days
Staphylococcus Vancomycin (or Naf if MSSA) 14-21 d

143.1.0.4 3⃣ Viral Meningitis

  • Enterovirus = #1 (summer/fall, faecal-oral)
  • HSV-2 (recurrent — Mollaret’s), VZV, mumps, HIV (acute), arbovirus
  • CSF: lymphocytic pleocytosis (10-1000), normal glucose, mild ↑ protein
  • PCR (enterovirus, HSV)
  • Tx: supportive; HSV PCR + → acyclovir; rest self-limited
143.1.0.4.1 Mollaret’s Meningitis
  • Recurrent aseptic meningitis
  • HSV-2 (most), HSV-1, autoimmune
  • Tx: acyclovir + valacyclovir suppression

143.1.0.5 4⃣ N. meningitidis 特殊

143.1.0.5.1 Disease
  • Petechiae / purpura (purpura fulminans in 嚎重)
  • DIC
  • Waterhouse-Friderichsen syndrome: adrenal hemorrhage + shock
  • Mortality 10-15% even with treatment
143.1.0.5.2 Treatment
  • Penicillin G 4 MU q4h OR Ceftriaxone 2g q12h × 7 days
143.1.0.5.3 Prophylaxis (Close Contacts)
  • Ciprofloxacin 500 mg PO ×1 OR Rifampin 600 mg BID × 2 d OR Ceftriaxone 250 mg IM ×1
  • Close contact: same household, kissing partners, healthcare workers exposed to oral secretions, daycare contacts (last 7 days)
143.1.0.5.4 Vaccination
  • MenACWY (Menactra, Menveo, MenQuadfi): routine 11-12 yr, booster 16
  • MenB (Bexsero, Trumenba): for outbreaks, high-risk groups
  • Asplenic / complement-deficient: both