161.1 🎓 醫孞生版

161.1.0.1 📌 䞀頁重點

  • 菌: Neisseria meningitidis — Gram - diplococcus (kidney bean shape), oxidase +, fermentor of glucose + maltose
  • Serogroups: A, B, C, W, X, Y — B + C + W 䞻流倧 outbreak; A 撒哈拉 meningitis belt; X 新興 W Africa
  • 臚床:
    1. Meningococcemia ± purpura fulminans + Waterhouse-Friderichsen syndrome
    2. Meningitis (頭痛/頞僵/燒/altered)
    3. 兩者 overlap 垞芋
  • Risk: 青少幎 + 軍/宿舍 + 朝聖 + ç„¡è„Ÿ + complement deficiency (C5-C9 + properdin + factor D) + eculizumab/ravulizumab (anti-C5) therapy
  • Treatment: Ceftriaxone 2 g IV q12h × 5-7d (or PCN G high-dose if susceptible)
  • Vaccines:
    • MenACWY (Menactra/Menveo/MenQuadfi) + MenB (Bexsero/Trumenba) + MenABCWY 五價 (Penbraya, FDA 2023)
    • ACIP: routine 11-12 + 16; MenB shared clinical decision-making 16-23
  • 接觞者 prophylaxis: ciprofloxacin / rifampin / ceftriaxone

161.1.0.2 1⃣ 现菌孞

  • Gram - diplococcus, “kidney bean” appearance
  • Oxidase + (vs Strep -)
  • Sugar fermentation: glucose + + maltose + (distinguishes from N. gonorrhoeae glucose-only)
  • Capsule polysaccharide → serogroup
  • Aerobe / CO2 enhanced (chocolate agar)
  • Nasopharyngeal carriage ~ 10% community (青少幎 higher)
161.1.0.2.1 Virulence
  • Capsule → 抗 complement + phagocytosis
  • LOS (lipo-oligosaccharide) = endotoxin → DIC, shock (高 quantity in meningococcemia)
  • Pili → adhesion to nasopharynx
  • Por proteins → outer membrane

161.1.0.3 2⃣ 臚床衚珟

161.1.0.3.1 A. Meningococcemia (Sepsis)
  • 急 onset (hours), 高燒, malaise
  • Petechial / purpuric rash (trunk + extremities; pathognomonic-ish)
  • 嚎重 → Purpura Fulminans (DIC + skin necrosis + digit loss)
  • Waterhouse-Friderichsen syndrome: bilateral adrenal hemorrhage + shock + 急性 adrenal insuf
  • Mortality 20-30% (with treatment); 90%+ untreated
161.1.0.3.2 B. Meningitis
  • 䞉聯 (頭痛, 燒, 頞僵): all-3 < 50%
  • Altered mental status, photophobia, vomit
  • CSF: 升 PMN, 葡萄糖 ↓, 蛋癜 ↑, gram - diplococci
  • Mortality 5-15%
161.1.0.3.3 C. 兩者 overlap 倚
  • 通垞 simultaneous
161.1.0.3.4 D. Chronic Meningococcemia
  • Rare; 敞週䜎燒 + 玅疹 + 關節痛 + 埌 sepsis/meningitis
161.1.0.3.5 E. Local Infections
  • Conjunctivitis, otitis, septic arthritis, pneumonia (W, Y serogroup)

161.1.0.4 3⃣ 蚺斷

  • Blood culture × 2 (75% +)
  • CSF gram stain + culture + PCR (PCR sensitive even after antibiotic)
  • Skin scrap gram stain of petechial — quick + (CDC method)
  • 䞍 wait culture — give antibiotic 立即 (LP if possible but don’t delay)

161.1.0.5 4⃣ 治療

161.1.0.5.1 A. Antibiotic
  • Empirical: Ceftriaxone 2 g IV q12h + vanco + dex if community meningitis
  • Confirmed N. meningitidis: ceftriaxone 2 g q12h × 5-7d 或 PCN G 4M U q4h
  • PCN-R rare globally but ↑ - ceftriaxone first
  • Macrolide / rifampin alternatives
161.1.0.5.2 B. Adjunct
  • Dexamethasone: 有限 evidence in N. meningitidis (vs strong S. pneumoniae) — IDSA 仍絊 empiric if cause unknown
  • IV fluid + vasopressor (severe sepsis)
  • Stress-dose steroid for Waterhouse-Friderichsen suspected
  • Limb compartment release if 血管壞死
161.1.0.5.3 C. ICU + 倚臟噚支持
  • DIC, ARDS, AKI, adrenal insuf
161.1.0.5.4 D. Surgical (Purpura Fulminans)
  • Debridement, skin graft, amputation late
  • Hyperbaric O2 (some center)
  • Protein C concentrate, activated PC (no longer recommend after PROWESS-SHOCK)

161.1.0.6 5⃣ Prophylaxis 接觞者

  • Indication: 家庭、宿舍、軍營、托嬰、24 hr aircraft seatmate, 醫護芪密接觞 (intubation, mouth-to-mouth)
  • Agent:
    • Ciprofloxacin 500 mg PO × 1 (易 — adult)
    • Rifampin 600 mg PO q12h × 4 doses
    • Ceftriaxone 250 mg IM × 1 (å­•å©Š)
    • Azithromycin 500 mg × 1 (alt)
  • 越早越奜 (24 hr); 14d 埌 less useful

161.1.0.7 6⃣ 疫苗 (2024 ACIP)

161.1.0.7.1 MenACWY (Conjugate)
  • Menactra (MenACWY-D) — 9 mo-55 yr
  • Menveo (MenACWY-CRM) — 2 mo-55 yr
  • MenQuadfi (MenACWY-TT) — ≥ 2 yr
  • 11-12 + booster 16 (routine ACIP)
  • 高 risk: ç„¡è„Ÿ, complement def, HIV, travel meningitis belt, military, lab worker
161.1.0.7.2 MenB
  • Bexsero (4CMenB, 2 doses) + Trumenba (rLP2086, 2-3 doses)
  • 16-23 yr (shared clinical decision-making)
  • College freshmen 宿舍 outbreak — strongly recommend
  • 高 risk: ç„¡è„Ÿ, complement def, eculizumab
161.1.0.7.3 Combined (2023+)
  • Penbraya (MenABCWY pentavalent, Pfizer, FDA 2023) — 1 shot 涵蓋 ABCWY
  • Simplifies schedule
161.1.0.7.4 Hajj 朝聖
  • 沙特芁求 MenACWY ≀ 3-5 yr 前