OSTEOMYELITIS

 

Etiology:

  1. Diseased bone secondary to trauma, FB (nail wound), prosthesis.
     
  2. Systemic disease (sickle cell), sepsis (hematological spread), IVDA.
     
  3. Contiguous skin infection (diabetic ulcers, sacral decubiti), human bite, PVD.
     
  4. Common pathogens are: S. aureus (most frequent), Pseudomonas (nosocomial or nail-through    sneaker wound, IVDA), streptococci (human bites), Salmonella (SCD), Bartonella henselae (AIDS), Pasteurella or Eikenella (animal bite), Mycobacterium (TB), anaerobes (ulcers, human bites).

S & S:

  1. Pain over underlying bone, fever, fatigue. These symptoms may vary: pt with paraplegia or pt who has neuropathy 2ry to DM will not experience pain.  In pt who had joint prosthesis and now develops joint instability 12-24 weeks later, the instability may be the only sign of osteomyelitis.

DX:

  1. Xray is the scout diagnostic tool. To be sensitive it requires disease to be present for over 7 -10 days.
     
  2. Bone scan and MRI are more definitive for establishing the diagnosis.
     
  3. Surgical sampling and/or needle biopsy are needed for proper diagnosis/treatment.  Swabs from ulcers are always multimicrobial and misleading.
     
  4. Blood cultures, WBC, ESR.

Treatment:

  1. Open wound FX - cefazolin 1gm IV
  2. Orthopedic surgery - prophylactic  1st  generation cephalosporin 30 min prior to skin incision (Vancomycin in hospitals with MRSA).
     
  3. Empirical treatment:
      • S. aureus:- Nafcillin 2 gm IV or Vancomycin 1 gm IV (if MRSA)
         
      • Enterobacteriaceae (Salmonella, Serratia): Ciprofloxacin 750mg
         
      • Pseudomonas: Ceftazidime 2gm IV + Ciprofloxacin 750mg
         
      • Anaerobes:  Clindamycin 600mg IV
         
      • Pasteurella/Eikenella:  ampicillin/clavulanate (Augmentin ) PO  or ampicillin/sulbactam (Unasyn) IV
         
  4. Surgical debridement.

 

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