Bone and Joint Infections arthritis

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Bone and Joint Infections arthritis Powered By Docstoc
					Bone and Joint Infections
   February 13, 2003
     Cass Djurfors
Objectives:
1. Osteomyelitis
2. Septic Arthritis

     Epidemiology
     Clinical features
     Diagnosis
     Management
            Epidemiology
Bimodal age distribution
   Under 20
   Over 50
Pediatrics:
   boys>girls
   Usually no identifiable risk factors
Adults:
   Usually have risk factors
Bone and Joint Infections:
Mechanism
   Hematogenous seeding most common
   Seeding from a contiguous source of
  infection
   Direct inoculation of the bone, from
  surgery, trauma or joint aspiration
Risk factors for bone and joint
infections:
   diabetes mellitus
   sickle cell disease
   AIDS
   alcoholism
   IV drug abuse
   chronic corticosteroid use
   preexisting joint disease
   other immunosuppressed states
  postsurgical patients—especially those with
  prosthetic devices
Pathogens:
   Bacteria are most common
   Viruses, fungi and parasites are possible
   Staph aureus most common in all ages
   except neonates
   GBS most common in neonates
   H. influenzae b has essentially disappeared
   as a pathogen in vaccinated children
Pathogens:
   Gonococcal arthritis is the most common
   type of septic arthritis in individuals under
   30 years old
   In the elderly, gram-negative bacteria
   account for a higher percentage of cases of
   bone and joint infections than in younger
   people
   MRSA, MRSE, and VRE have emerged as a
   significant microbiologic problem in the past
   decade
Pathogens:
   Usually unimicrobial
   Polymicrobial (36 to 50%) more likely
  in diabetic foot osteomyelitis,
  posttraumatic osteomyelitis, chronic
  osteomyelitis, and chronic septic
  arthritis
Osteomyelitis: Presentation
   May be acute or chronic
   Pain over the affected bone
   In children: limp or refusal to weight
   Localized warmth, swelling, and erythema
   Fever is inconsistently present
   Systemic complaints often reported:
  headache, fatigue, malaise, and anorexia
Osteomyelitis: Presentation
   Point tenderness over the infected
  segment
   Palpable warmth and soft-tissue
  swelling with erythema may be present
Osteomyelitis: Diagnosis
  WBC is neither sensitive nor specific
     Values commonly range from normal to
      15,000/mm3
  ESR usually elevated
     One series reported 90% sensitivity
     Very nonspecific however
     Can be used to follow treatment
  CRP
     yet another nonspecific marker of inflammation
Osteomyelitis: Diagnosis
  Plain films:
     Low sensitivity early in the disease
     3-5 days: may detect soft tissue edema
     7-10 days: >66% still have normal x-rays
     30-50% of bone mineral must be lost to detect
      lucency on plain film
     By 28 days, >90% of plain films will be positive
     Characteristic finding: lucent lytic lesions of
      cortical bone destruction
     Advanced disease: lytic lesions are surrounded by
      dense, sclerotic bone, and sequestra may be
      noted
Plain radiograph of tibia. Lucent areas in metaphysis are sites of
advanced osteomyelitis
Plain radiograph of humerus. Distal
portion of humerus has involucrum
 formation, representing advanced
case of osteomyelitis.
Osteomyelitis: Diagnosis
  Bone Scan:
     More useful early on than plain radiographs
     Can detect osteomyelitis within 48 to 72
      hours of disease onset
     Sensitivity 90% with technetium-99 scan
     False positive rate as high as 64%
        Trauma, surgery, tumours, soft tissue infection
Example of gallium (top) and
technetium (bottom) bone
scans in advanced osteomyelitis
of tibial metaphysis. Both scans
show increased radionuclide
uptake.
Osteomyelitis: Diagnosis
  111   In-labeled WBC scan
     Can distinguish infected bone from bone
      that has increased turnover from fractures,
      surgery, prostheses, osteoarthropathy, and
      tumor
     Usually reserved for situations of equivocal
      or normal bone scans in patients where
      osteomyelitis is still a consideration
Osteomyelitis: Diagnosis
  CT
     Used for infection in bones that are difficult to
      visualize on plain radiographs and bone scans:
      sternum, vertebrae, pelvic bones, and calcaneus
     Appears as rarefaction, or lucent areas, on the CT
      scan images
     Gas may also be visible in bony abscess cavities
     Limitation: disease must be present for > 1 week
Osteomyelitis: Diagnosis
  MRI
     Good for early detection
     Limited availability
Osteomyelitis: Diagnosis
  Microbiologic Diagnosis:
     Needle aspiration or surgical specimen is
      best
     Swab of draining wound or sinus is not
      adequate
     Blood cultures in untreated patients are
      positive ~50% of the time
Differential Diagnosis:
  Tumour:
     Osteoid osteoma, chondroblastoma,
      Ewing’s sarcoma, metastases, lymphoma
  Trauma
  Myositis ossificans
  Erythema nodosum
  Cellulitis
  Eosinophilic granuloma
Osteomyelitis: Management
  IV Antibiotics
     Empiric broad spectrum initially
     Narrow appropriately when sensitivities available
     4-6 weeks
  +/- Surgical debridement
     Often not needed for acute hematogenous
      osteomyelitis in children
     Required in the diabetic foot or chronic
      osteomyelitis
  HBO
     Controversial
Special considerations
  Kids: usually acute hematogenous and often
  responds to Abx alone
  Vertebral osteomyelitis
     Risk of paralysis!
     Watch for epidural abscess
     Careful with back pain and fever in IVDU
  Post-traumatic osteomyelitis:
     10% of open fractures
     2% with puncture wounds: Pseudomonas
      aeruginosa and S. aureus
Special considerations
  Diabetic foot:
     Usually chronic and polymicrobial
     Surgical debridement almost always
      required
     Amputation often required
  Sickle cell disease:
     Increased risk of osteomyelitis
     S. aureus and Salmonella species
Empiric Therapy Adults: CHA
   Osteomyelitis              Pathogen             Therapy
Hematogenous              S. aureus        Cloxacillin or Cefazolin
                                           +/- Gentamicin
IVDU                      S. aureus        Cloxacillin or Cefazolin
                          P. aeruginosa     + Gentamicin
Contiguous: vascular      Polymicrobial    Clinda + Cipro or
insufficiency, diabetic                    Ancef + Metronidazole
foot                                       Severe: imipenem or pip-
                                           tazo
Nail-puncture of foot     P. aeruginosa    Prophylaxis: cipro
                                           Treatment:pip-tazo +
                                           tobramycin
Post-op prosthetic        S. aureus        Vancomycin +
joint                     S. epidermidis   Gentamicin
Empiric Therapy Kids: CHA
   Osteomyelitis             Pathogen                Therapy
Neonates                GBS, S. aureus,        Cloxacillin +
                        Enterobacteriaceae     Cefotaxime
Children                S. aureus, Strep, H.   Cloxacillin
                        flu
Sickle cell             S. aureus,             Cloxacillin +
                        Salmonella sp.         Cefotaxime
Post-op                 S.aureus, GAS,         Cefazolin +/-
                        Enterobacteriaceae     Gentamicin
Post-op spinal rods     S. aureus, CNS, GAS, Vancomycin +
or sternotomy           Enterobacteriaceae, Gentamicin
                        Pseudomonas
Nail puncture of foot   Pseudomonas            Piperacillin+Tobra or
                        aeruginosa             Ceftazidime + Tobra
Disposition:
  Inpatient
  Outpatient IV antibiotic therapy
  Outpatient PO antibiotic therapy
  (usually as step-down)
Septic Arthritis: Presentation
  Usually hematogenous but may also result
  from contiguous spread or direct inoculation
  Occurs in all age groups
  Most common in children
  Usually monoarticular
  Polyarticular in less than 10% of pediatric
  cases and less than 20% of adult cases
  Hip and knee are most frequently affected
Septic Arthritis: Presentation
  Predisposing factors:
     Any joint disease
        Osteoarthritis
        Gout
        Rheumatoid arthritis
     Surgery
     IVDU
Septic Arthritis: Presentation
  Usually acute in onset
  Joint pain is main feature – worse with
  movement (careful with immunosuppressed
  and steroid dependent patients)
  Kids may refuse to use the affected limb
  Fever - 80% of children, > 40% of adults
Septic Arthritis: Presentation
  Physical exam:
     Joint is held in position of greatest comfort, slight
      flexion
     Swelling, erythema, and warmth in almost all
      cases
     Palpation of the septic joint causes exquisite pain
     Both flexion and extension of the joint cause
      severe pain
     Effusion
Septic Arthritis: Diagnosis
  Joint fluid for culture and analysis
  Knee joint is both the most likely to be
  infected and the easiest to aspirate in the ED
   Other joints (hip) may require ortho
  consultation +/- ultrasound or fluoroscopy-
  guided aspiration
  Iatrogenic septic arthritis occurs in less than 1
  in 10,000 joint injections or aspirations
Septic Arthritis: Diagnosis
  Joint fluid:
     aerobes, anaerobes and fungi
     Gram stain
     Cell count and differential - wbc > 50000/mm3
     Glucose – decreased in septic arthritis with joint
      fluid/serum glucose ratio < 1:2.
  Synovial tissue from arthroscopy can be
  helpful in diagnosis
Septic Arthritis: Diagnosis
  Blood cultures positive in 25% to 50%
  of cases
  ESR elevated in ~90%
  WBC may or may not be elevated
  Plain radiographs not very helpful
  except to reveal joint effusion
  Bone scan will be ―hot‖ but causes
  unnecessary delay
Special Considerations:
  Kids:
     More common than osteomyelitis
     Of all cases in kiddies, 2/3 under age 2
     Neonates: GBS, S. aureus, GNB
     >3 months: S. aureus > GAS > S. pneumo
  Teenagers and young adults:
     N. gonorrhoeae
     Most are symptomatic with genital/oral infection
     Classic triad of disseminated gonococcal infection
      is migratory polyarthritis, tenosynovitis, and
      dermatitis
     Joint fluid may be negative…treat on suspicion
Septic Arthritis: Differential
  Kids
      Osteomyelitis
      JRA
      Transient synovitis
      Legg-Calvé-Perthes disease
      Slipped capital femoral epiphysis
      Rheumatic fever
Septic Arthritis: Differential
  Adults:
      Osteomyelitis
      Gout
      Pseudogout
      Reiter’s syndrome
      Psoriatic arthritis
      Arthritis associated with inflammatory bowel
       disease and ankylosing spondylitis
      Traumatic hemarthrosis
Septic Arthritis: Management
  Orthopedic emergency
  Immediate IV Abx
  Needle vs. surgical decompression
  Abx alone in gonococcal arthritis only
Septic Arthritis: CHA Adults
Septic Arthritis       Pathogen               Antibiotics
Adults (native joint   S. aureus, P.          Cloxacillin or
+/- penetrating        aeruginosa             cefazolin +/-
trauma)                                       gentamicin
Gonococcal             N. gonorrhoeae         Cefotaxime

Rheumatoid arthritis   S. aureus, Strep sp,   Cefazolin +/-
                       Enterobacteriaceae     gentamicin
Prosthetic joint       S. aureus, S.          Vancomycin +
                       epidermidis, others    gentamicin
IVDU                   S. aureus, P.          Cloxacillin or
                       aeruginosa             cefazolin +/-
                                              gentamicin
Septic Arthritis: Kids
 Septic Arthritis Pathogen         Antibiotics
 Neonates         GBS, S.          Cloxacillin +
                  aureus,          Cefotaxime
                  Enterbacteriac
                  eae
 Children         S. aureus,       <5yrs:
                  Strep sp.,       cefuroxime
                  rarely H. flu    >5yrs:Cloxacilli
                                   n or cefazolin
 Sexually active N.                Cefotaxime
                 gonorrhoeae
Septic Arthritis: Disposition
  Diagnostic joint fluid aspirate or high clinical
  suspicion requires admission
  Non-diagnostic aspirates with equivocal
  clinical findings may be discharged home and
  re-evaluated in 24 hours
  Be conservative (consider admission) for
  patients with joint disease, prosthetic joints
  or immunosuppression and suspected septic
  arthritis