155.1 🎓 醫孞生版

155.1.0.1 📌 䞀頁重點

  • C. diphtheriae: gram + rod, club-shaped, metachromatic granules (Loeffler stain)
  • Exotoxin (β-phage carried): ADP-ribosylate EF-2 → 蛋癜合成 stop
  • 臚床: respiratory diphtheria (pseudomembrane 灰癜芆扁桃 → 窒息), cutaneous, myocarditis, polyneuritis
  • DAT (Diphtheria Antitoxin) æ•‘å‘œ — equine, hypersensitivity test 先
    • 抗生玠: erythromycin 或 PCN G
  • Vaccine: DTaP / Tdap (toxoid)
  • 2022-2024 Outbreak: Ukraine, Pakistan refugee, Yemen
  • Non-diphtheriae: C. jeikeium (JK, hospital-acquired), C. urealyticum (UTI), C. ulcerans (zoonotic, milk), C. minutissimum (erythrasma)

155.1.0.2 1⃣ C. diphtheriae

155.1.0.2.1 现菌孞
  • Gram + rod, pleomorphic, club-shaped
  • Metachromatic granules (Loeffler stain → blue-purple)
  • Culture: tellurite media (gray-black)
  • 3 biotypes: gravis, mitis, intermedius
155.1.0.2.2 臎病機蜉
  • β-corynephage 携垊 tox gene → exotoxin
  • Exotoxin: A subunit ADP-ribosylates EF-2 (elongation factor 2) → 蛋癜合成停 → 现胞死
  • 黏膜壞死 → pseudomembrane (fibrin + 现胞 debris + neutrophils + 菌)
155.1.0.2.3 A. Respiratory Diphtheria
  • 望䌏 2-5 d
  • 喉嚚痛、癌燒、䞍適
  • Tonsil/pharynx 灰癜色 pseudomembrane (拉撥血腫); 可蔓延 larynx → stridor → 窒息
  • é ž LAP + 軟組織腫 (“bull neck”)
  • Toxic complications:
    • Myocarditis (1-2 wk, T-wave 反蜉, AVB, CHF) - mortality cause
    • Polyneuritis (3-7 wk, palatal paralysis 先, → 党身)
    • Renal failure
155.1.0.2.4 B. Cutaneous Diphtheria
  • 熱垶, 街友, IDU
  • 慢性, 䞍癒合, “punched-out” 邊
  • 通垞合䜵 GAS / S. aureus

155.1.0.3 2⃣ 蚺斷

  • Clinical suspicion + culture (tellurite)
  • Elek test or PCR for tox gene — 確認 toxigenic
  • 通報 (notifiable disease)
  • 䞍等培逊 — 治療立即啟動

155.1.0.4 3⃣ 治療

155.1.0.4.1 A. DAT (Diphtheria Antitoxin) — æ•‘å‘œ
  • Equine antiserum
  • 越早越奜 (神經元䞀旊受 toxin 䞍可逆)
  • 劑量 by site + severity:
    • Pharyngeal mild: 20,000-40,000 U IM/IV
    • Larynx + neck: 40,000-60,000 U
    • Severe/extensive: 80,000-100,000 U
  • Hypersensitivity test 先 (銬血枅過敏)
  • Pre-medication: antihistamine + steroid
155.1.0.4.2 B. 抗生玠
  • Erythromycin 500 mg PO/IV qid × 14d OR
  • Procaine PCN G 600,000 U IM q12h × 14d
  • 䞻芁 eradicate carrier state — 䞍取代 DAT
155.1.0.4.3 C. Supportive
  • Airway (tracheostomy if obstruction)
  • Cardiac monitor (myocarditis EKG)
  • Bedrest (myocarditis)
  • IV fluid + nutrition
155.1.0.4.4 D. 隔離
  • Respiratory isolation × 48hr after antibiotic
  • Eradication: 2 - throat cx 埌解陀
  • 接觞者 → throat cx + prophylaxis erythromycin × 7-10d + booster vaccine

155.1.0.5 4⃣ 預防

  • Toxoid (DTaP, Tdap, Td)
  • DTaP × 5 (2, 4, 6, 15-18 mo, 4-6 yr)
  • Tdap (adolescent + 1 in adulthood)
  • Td booster q10y
  • 2022-2024 Outbreak — 烏俄戰爭, 難民營 → 補霊 vaccine

155.1.0.6 5⃣ 非 diphtheriae Corynebacterium

155.1.0.6.1 A. C. jeikeium (JK group)
  • Multi-drug R 醫院 isolate
  • Catheter / device infection, bacteremia, IE in immunocompromise
  • Vancomycin (intrinsic R β-lactam)
155.1.0.6.2 B. C. urealyticum
  • UTI alkaline stones, encrusted cystitis (struvite-like)
  • Vancomycin or linezolid
155.1.0.6.3 C. C. ulcerans
  • Zoonotic (cattle, milk), human diphtheria-like
  • Tox gene 可有 → DAT 也甚
  • Risk: dairy worker, animal contact
155.1.0.6.4 D. C. pseudotuberculosis
  • Sheep, lymphadenitis
  • Rare in human
155.1.0.6.5 E. C. minutissimum
  • Erythrasma: 灰棕色 patch, intertriginous (axilla, groin)
  • Coral-red Wood’s lamp
  • Erythromycin topical or oral
155.1.0.6.6 F. C. diphtheriae 非 toxigenic
  • 可造 endocarditis (rare)
  • 培逊 + 埌 elek/PCR 看 toxigenicity