158.1 🎓 醫孞生版

158.1.0.1 📌 䞀頁重點

  • 菌: Clostridium botulinum — Gram + anaerobic rod, spore
  • 毒玠: Botulinum toxin (BoNT, types A-G) — 最毒 toxin known to man
    • 阻止 ACh release at NMJ pre-synaptic → flaccid paralysis
    • Cleaves SNAREs (SNAP-25, syntaxin, VAMP — 䟝 type)
  • 臚床圢匏:
    1. Foodborne (preformed toxin in canned/preserved food)
    2. Infant (gut colonization, < 1 yo, honey)
    3. Wound (IDU “black tar” heroin)
    4. Iatrogenic (cosmetic over-dose)
    5. Inhalational (bioterror)
  • Cardinal: 4 D’s — diplopia, dysarthria, dysphonia, dysphagia + descending symmetric flaccid + bulbar palsy → respiratory failure
  • Sensorium clear, no fever, NO sensory loss
  • Treatment: Heptavalent BAT (Botulism Antitoxin Heptavalent) IV → supportive vent
  • Infants: BabyBIG (human IVIG anti-BoNT) 取代 equine BAT

158.1.0.2 1⃣ 现菌 + 毒玠

  • C. botulinum: Gram + anaerobe, soil + sediment
  • 7 serotypes (A-G); human disease 䞻芁 A, B, E, F (A, B 食源; E æµ·é®®)
  • Botulinum toxin = 神經毒, LD50 in human ~ 1 ng/kg (䞖界最毒生物毒)
  • Heat-labile (80°C × 30 min destroy) — 重新煮 home-canned 可防
158.1.0.2.1 機蜉
  • BoNT 進入 motor nerve terminal at NMJ
  • Zinc metalloprotease 切 SNAREs:
    • Type A, E: SNAP-25
    • Type B, D, F, G: VAMP (synaptobrevin)
    • Type C: SNAP-25 + syntaxin
  • → 阻止 ACh vesicle fusion + release
  • → Flaccid paralysis (chick wedge of skeletal m. + autonomic anticholinergic)
  • 神經元 sprouting 需 months → recovery 慢

158.1.0.3 2⃣ 臚床衚珟

158.1.0.3.1 A. Foodborne Botulism
  • Preformed toxin in canned/preserved low-acid food (vegetables, fish, honey, “fermented” 食品)
  • 望䌏 12-72 hr
  • Bilateral CN palsies first (ptosis, EOM, dysarthria, dysphagia, dry mouth)
  • Descending symmetric flaccid paralysis → respiratory failure
  • GI prodrome (nausea, vomit, abdominal pain) 可有可無
  • Sensorium clear, normal sensory exam, normal Pupils (slow + dilated 埌期)
  • Death: 呌吞肌癱
158.1.0.3.2 B. Infant Botulism
  • < 1 yr (peak 2-6 mo)
  • Spores germinate in gut (gut microbiome immature)
  • Honey classic source (䞍芁絊 < 1 yr) but most no honey hx
  • Sx: constipation 先 → 喝奶差 → floppy infant + descending palsy + ptosis + 哭聲匱 + 呌吞困難
  • “Floppy baby” — 鑑別 SMA, hypothyroid, congen myasthenia
  • Treatment: BabyBIG (human IV — 取代 equine BAT)
  • 通垞 good recovery
158.1.0.3.3 C. Wound Botulism
  • IDU “black tar heroin”, contaminated wound
  • 望䌏 4-14d
  • CN palsies + descending — no GI sx
  • Debridement + antibiotic (metronidazole or PCN) + BAT
158.1.0.3.4 D. Iatrogenic
  • Cosmetic / spasticity botox over-injection
  • 倚 muscle weakness 局郚 → systemic
  • BAT if severe
158.1.0.3.5 E. Adult Intestinal Toxemia
  • Rare, after surgery / antibiotic disrupting flora
158.1.0.3.6 F. Inhalational (Bioterror)
  • 24-72h CN palsies + descending
  • Stockpiled BAT — CDC release

158.1.0.4 3⃣ 蚺斷

  • 臚床䞻芁 — confirmatory lab 慢
  • Mouse bioassay (CDC) — toxin in serum/stool/food (gold std but 4-7 d)
  • PCR / mass spec for toxin gene — newer
  • EMG: NMJ pre-synaptic defect — incremental response at high-freq stim (50 Hz) ↔ vs myasthenia (decremental at low freq)

158.1.0.5 4⃣ 治療

158.1.0.5.1 A. 䞭和 toxin
  • Heptavalent BAT (Botulism Antitoxin, equine-derived, all types A-G) ASAP
  • CDC 24/7 hotline (USA), Taiwan CDC 戰備 stockpile
  • äž­å’Œ unbound toxin only; å·² internalized 䞍可逆 → 等 neural sprouting
  • 過敏 risk (銬 serum) — pre-medicate
158.1.0.5.2 B. Infant Botulism
  • BabyBIG (human-derived IVIG anti-BoNT A/B)
  • 瞮短 ICU + LOS (UCSF study)
  • 由 California Department of Public Health 統管
158.1.0.5.3 C. 抗生玠 (Wound only)
  • Metronidazole 或 PCN G
  • 食源 / infant: 䞍必 antibiotic (其寊 aminoglycoside 還可胜 worsen — NMJ block)
158.1.0.5.4 D. 支持
  • Mechanical ventilation (weeks-months)
  • Tracheostomy
  • Enteral feed (gastroparesis 可有)
  • DVT prophylaxis
  • 埩健

158.1.0.6 5⃣ 預防

  • Home-canned 食品: 高溫高壓 (≥ 116°C × 20-100 min) destroy spores
  • Reheat: 80°C × 30 min destroy toxin
  • < 1 yr: NO honey
  • Refrigerate fermented food
  • Wound 枅創 (IDU)