159.1 🎓 醫孞生版

159.1.0.1 📌 䞀頁重點

  • 菌: Gram + anaerobic spore-formers — C. perfringens (#1), C. septicum, C. novyi, C. histolyticum, C. sordellii
  • 臚床:
    1. Gas gangrene (clostridial myonecrosis): 急 + 臎呜 + crepitus + bullae + 高劇痛
    2. Cellulitis without myonecrosis (clostridial anaerobic cellulitis)
    3. 食物䞭毒 (C. perfringens type A): 倧腞 toxin, watery 腹瀉 8-16 hr
    4. C. septicum bacteremia: ~ 50% + GI malignancy / leukemia — 必查 colonoscopy
    5. C. sordellii: post-partum, post-abortion, IDU, MIFEPRISTONE-induced → TSS-like 死亡 quickly
  • 治療: emergent surgical debridement + PCN G high-dose + Clindamycin (toxin suppression) + ICU + ± HBO

159.1.0.2 1⃣ 现菌孞

  • Gram + anaerobic rods, spore-forming
  • 廣存土壀、糞、GI tract
  • C. perfringens: capsule, double-zone hemolysis, lecithinase + (Nagler)
  • Toxins: α-toxin (lecithinase/phospholipase C) — 现胞膜溶, hemolysis, vascular leak
    • Ξ-toxin (perfringolysin O — cholesterol-dependent cytolysin)
    • κ, ÎŒ, Îœ — collagenase, hyaluronidase

159.1.0.3 2⃣ Gas Gangrene (Clostridial Myonecrosis)

159.1.0.3.1 流行病孞
  • Trauma 埌 (deep wound, devitalized muscle): 戰爭 / 工傷 / 車犍 (åžž C. perfringens)
  • Spontaneous (C. septicum): 無 trauma; GI malignancy / 結腞癌 / 癜血病 translocation source
159.1.0.3.2 臚床
  • 望䌏 6 hr - 4 d 短
  • 超 disproportionate pain at wound
  • 皮膚: bronze / dusky / hemorrhagic bullae / brownish 滲液
  • Crepitus (gas in soft tissue 觞感)
  • 急快 systemic toxicity: tachycardia, sepsis, ARDS, AKI, DIC, hemolysis
  • 死亡可圚 hours 內 if not treated
159.1.0.3.3 圱像
  • X-ray / CT: gas in soft tissue / muscle (linear / feathered)
  • CT 為 emergent confirm + extent
159.1.0.3.4 治療
  1. EMERGENT 倧幅 surgical debridement (重耇 q24h) ± amputation
  2. PCN G 4 M U IV q4h + Clindamycin 900 mg IV q8h (PCN — bactericidal, clinda — toxin suppression)
  3. Vanco + pip-tazo (cover GAS, polymicrobial NF — 之前 empirical)
  4. ICU resuscitation, vasopressor
  5. Hyperbaric Oxygen (HBO) — controversial, 有 center capable 可 adjunct (delay 䞍 should䞍該 delay surgery)
  6. IVIG — 郚仜 evidence

159.1.0.4 3⃣ C. septicum

  • Spontaneous gas gangrene (no trauma)
  • ~ 50-80% + occult GI malignancy (colon CA, GI lymphoma) or hematologic malignancy (acute leukemia, neutropenic)
  • 嚎重 hemolysis, DIC, mortality 高
  • 必查 colonoscopy + GI workup post-treatment

159.1.0.5 4⃣ C. perfringens Food Poisoning

  • Type A, 廣存
  • 廠商 倧量烹煮 + 保溫 → spores germinate → toxin
  • 望䌏 8-16 hr
  • Crampy abdominal pain + watery diarrhea, no vomit, no fever
  • Self-limited 24 hr
  • 倧量 outbreak (cafeteria, institutional)
  • 通報 (Public Health)
  • Tx: 支持; 無抗生玠

159.1.0.6 5⃣ C. sordellii

  • Post-partum, post-abortion (medical / surgical)
  • IDU “skin popping” black tar heroin
  • 2005 mifepristone-induced abortion cases USA
  • TSS-like: shock + leukemoid reaction + hemoconcentration + 無癌燒
  • Mortality 高 (80%+)
  • Tx: debridement + PCN + clinda + ICU

159.1.0.7 6⃣ Anaerobic Cellulitis (without myonecrosis)

  • Gas + crepitus 䜆 muscle uninvolved (subcutaneous only)
  • Less toxic systemically
  • 倚 polymicrobial
  • 處理同 debridement + 抗生玠

159.1.0.8 7⃣ C. tertium

  • Gram + 䜆 aerotolerant (難認)
  • Neutropenic enterocolitis, bacteremia
  • PCN/clinda R — 甹 vanco/metronidazole