136.1 🎓 醫孞生版

136.1.0.1 📌 䞀頁重點

  • 分類:
    • Acute hematogenous (兒童 long bone metaphysis; 成人 vertebra) — S. aureus #1
    • Contiguous (鄰近 SSTI, post-op, trauma) — polymicrobial
    • Diabetic foot — polymicrobial (Staph, Strep, Gram -, anaerobes)
    • Vertebral (成人最垞 osteo) — S. aureus; TB (Pott’s); Brucella
    • Prosthetic / implant — biofilm: S. epidermidis (CoNS), S. aureus, P. aeruginosa
  • 蚺斷:
    • MRI = gold (sensitivity 90%+); CT for bone fragments
    • Bone culture (biopsy or aspirate) = essential — antibiotic 之前
    • ESR, CRP ↑↑; WBC variable
  • 治療: 6 週 IV standard (Vanc + 3rd gen ceph) → de-escalate; surgery if abscess / dead bone / refractory
  • 22E update: POET trial-like oral switch for stable osteomyelitis (OVIVA trial 2019, NEJM)

136.1.0.2 1⃣ 病原 by Context

情境 䞻芁病原
Adult community, hematogenous S. aureus (MSSA + MRSA), GBS, GAS
Children long bone S. aureus, K. kingae, S. pyogenes
Sickle cell Salmonella (#1), S. aureus
IVDU S. aureus, Pseudomonas (rare), Candida
DM foot Polymicrobial: S. aureus, Strep, Enterobacteriaceae, anaerobes, Pseudomonas
Vertebral S. aureus #1, GN (E. coli, Pseudomonas), TB, Brucella, fungi
Prosthetic joint / implant CoNS (S. epidermidis), S. aureus, P. acnes (shoulder), Enterobacteriaceae
Post-puncture wound foot Pseudomonas through sneaker (classic)

136.1.0.3 2⃣ 臚床衚珟

136.1.0.3.1 Acute Hematogenous (兒童)
  • 急性癌燒、骚痛、肢體 limping
  • Long bone metaphysis (femur, tibia)
  • ESR/CRP ↑↑
  • MRI 早蚺; bone scan alt
136.1.0.3.2 Vertebral Osteomyelitis (Adult, 最垞芋成人骚髓炎)
  • 老人 / DM / 透析 / IVDU
  • Insidious back pain (weeks), low-grade fever (50%), neuro 猺倱 (compression)
  • Imaging: MRI with contrast (sensitivity 95%+) — vertebral body + endplate + disc
  • Source: hematogenous (UTI, IE, IV catheter); contiguous (epidural injection); IVDU
  • Workup: blood cultures × 2, TB workup, CT-guided biopsy (if cultures negative)
  • Treatment: 6-12 wks IV antibiotic per organism
  • Surgical: epidural abscess + neuro deficit; spinal instability; refractory
136.1.0.3.3 DM Foot Osteomyelitis
  • Probe-to-bone test positive (sensitivity ~ 60%, specificity > 90%)
  • MRI for staging
  • Biopsy (deep wound culture, not superficial swab)
  • Treatment: 6 wks IV (or oral if stable + culture-directed) + offloading + glycemic + revascularization if PAD
136.1.0.3.4 Prosthetic Joint Infection (PJI)
  • Acute (< 3 mo post-op) / Delayed / Late
  • DAIR (debride, antibiotic, implant retention) if early acute + sensitive organism
  • 2-stage revision (gold standard): explant → cement spacer + 6 wk IV → reimplant
  • Rifampin add-on for staph (penetrates biofilm)

136.1.0.4 3⃣ 治療

136.1.0.4.1 Empirical
  • Vancomycin + Ceftriaxone (community, hematogenous)
  • Vanco + Pip-tazo / Cefepime (DM foot, hospital, severe)
  • Pediatric: Cefazolin (MSSA) or Vanco (MRSA) + Ceftriaxone
136.1.0.4.2 Specific Organism
Organism Treatment Duration
MSSA Cefazolin OR Nafcillin 4-6 wks IV
MRSA Vancomycin / Daptomycin / Linezolid 4-6 wks
Strep Penicillin / Ceftriaxone 4-6 wks
Pseudomonas Cefepime / Pip-tazo / Ceftolozane + aminoglycoside 6 wks
Salmonella Ceftriaxone 4-6 wks (sickle cell)
TB (Pott’s) RIPE × 2 mo + INH/RIF × 7-10 mo 9-12 mo
Brucella Doxy + Streptomycin or Rifampin 6 wks
Fungal Amphotericin B → azole months
136.1.0.4.3 Oral Switch (22E paradigm)
  • OVIVA trial (NEJM 2019): oral non-inferior to IV after 1-2 wks IV (in selected stable patients)
  • Oral choices: linezolid, fluoroquinolone + rifampin (staph), TMP-SMX, doxycycline
  • Requires good oral bioavailability + culture confirmation