Management of Septic Arthritis

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Management of Septic Arthritis

• Craig Wiseman

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Pyarthrosis

• Pyon pus
• 0.2-0.7 of hospital admissions
• Peak incidence in the first years of 1st decade
  and 50 years
• MalesFemales
• LEUE

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Mechanisms

• Hematogenous spread local or distant
• Local - injections, surgery, penetrating inj.
• Distant - Sinusitis, brochiectasis, IVDU
• Direct inoculation
• Host factors
• Immunosuppression due to chronic disease,
  chemotherapeutic agents
• Local factors
• Trauma, prior arthritis, methylmethacrylate

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Kochs postulates

• The organism must be identified at the site
• The organism must not be found in other diseases
• The organism must be able to produce the disease
  in other animals
• The organism must be identfied in the disease
  that is produced

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Pathophysiology

• Synovial joint vascular, no BM in synovium,
  transudate, avascular cartilage
• Joint has limited ability to clear bacteria
• Esp. pyogenic bacteria
• Present early in synovium and joint
• Within hrs synovitis fibrinous exudate and
  necrosis

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Inflamatory Response

• PMN, synovial cell enzymes
• Proteases, peptidases, collagenases that degrade
  cartilage matrix
• Gram negative bacteria and S. Aureus also release
  proteolytic enzymes or have direct effect on
  matrix
• First change is loss of proteoglycan matrix
• As early as 8 hrs. reversible
• Cartilage becomes stiff and increase mech
  stress
• Collagen damage is next producing visual changes
  irriversible
• Do need live organisms for this destructive cycle
• End result can be large pannus formation,
  arthrofibr or ankylosis

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HP

• Painful ROM, swelling, erythema, not bearing
  weight, recent illnesses
• Children
• pseudoparalysis or disuse of limb, not septic
• antalgic limp
• Fevers not consistent
• Have parent examine the child

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Labs

• Leukocyte count not reliable early stages
• 25 of children had elevated counts and 65 the
  diff was abnormal
• ESR
• Nonspecific test of inflammation
• Affected by cell size, shape and protein content
• i.e. sickle cell, anemia, steroids
• Not reliable in neonates
• Elevated in 48-72 hrs returns to baseline 2-4
  weeks
• Mayo series, Morey et al
• only 5 of 76 had ESR below 20mm/hr,
• elevated in 90 of patients w/ septic arthritis

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ESR

• No change w/ antibiotic therapy
• Continues to rise 3-5 days after this may
  consider change in tx
• Not good for early evaluation of tx

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CRP

• Rises within 6 hrs and peaks 30-50hrs
• Half life 47hrs
• Makes this marker of greater value for early
  diagnosis and resolution of inflammation
• CRP is elevated in trauma, in otitis
  media(22bacterial 65 viral)

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Cultures

• Blood cultures
• yield organisms 30-50 of cases
• Decreases w/ previous antibiotic therapy
• Aspiration of joint fluid
• Gram stain, leukocyte cell count, PMNs
• Cell counts 80,000 100,000/ml likely septic
  arthritis
• Frank and Nelson 126 positive culture
• Counts of 50,000/ml or less in 55, 34 had
  100,000/ml
• Other inflammatory processes can give you
  80,000/ml
• Gram stain can give you a presumptive early
  diagnosis
• 1/3 are positive

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Differential Diagnosis

• Transient synovitis of the hip
• Self limited post-infectious arthritis
• Predominantly in boys 70 3-10 years old
• Usually preceded by URI or trauma
• 4 bilateral
• Low grade fever, mildly elevated ESR and WBC
• positive effusion on U/S
• Cyclical Recurrence in 4-17 in 6 months
• Less painful than septic joints
• Tx NSAIDS and observe, resolution in 2 weeks

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JRA

• Gradual onset
• Remains ambulatory
• Good ROM inspite of large effusion
• Can have cell counts 100,000/ml
• Other causes of aseptic arthritis
• Rheumatic fever, HSP, Salmonella, Yersinia
  enteroarthritis, Kawasaki disease, and serum
  sickness, sickle cell disease?

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Kocher et al. 1999

• Hx of fever
• Nonweightbearing
• ESR 40mm/hr
• WBC 12,000/mm3

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Imaging

• Ultrasound
• Used frequently in pediatrics assessing the hip
  for effusion/dislocations
• Cannot differentiate between TSH and septic
  arthritis by positive effusion alone
• If extracapsular effusion may distinguish between
  osteomyelitis around hip/pelvis
• Bone scan better in osteomyelitis(92)
• Equally Increased uptake on both sides of the
  joint 90 of septic joint had a positive bone
  scan
• MRI sensitivity 97 and specificity 92

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Microbiology

• Gonococcal arthritis is the most common cause of
  septic arthritis in the healthy adult
• S. aureus most common nongonococcal bacterial
  arthritis 40-60 of cases
• Streptococcal species 27, gram negative 23, S.
  epi 4, diplococcus pneumoniae 6
• Staphylocci make up 77 nongonococcal infections
• Gram positive cocci most common post-op ortho
  infection 60-80
• Arthroplasty of hip and knee Staph aureus and
  epidermis are equally common, mixed and gram neg
  sepsis have poorer outcomes

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Gonoccocal Arthritis

• Most common in women in the 2nd and 3rd decade
• Dissemination of GU infection
• Associated in adolescence w/ pregnancy,
  menstration, low progesterone activity
• Suspect child abuse in prepubescent girls
• Presentation
• Rash(1/3), tenosynovitis of dorsal wrist/hand,
  polyarthralgia(80), knee most common
• Wbc count elevated (2/3)
• Culture of joint fluid and genital tract
• Treatment
• DOC ceftriaxone
• Debridement if hip involved, serial aspirations
  if knee, surgery if grossly purulent w/ drains

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Pediatric organisms

• Neonates (birth 6 weeks)
• Group A or B streptococcus
• DOC cefotaxime or ceftriaxone
• Children under 3-4 y/o
• Kingella kingae now greater than H. flu due to
  vaccination
• Tx w/ pcns or cephalosporins
• Strep. Pneumococcus 30-40 are resistent to
  pcn/cephalosporins
• DOC is ceftriaxone

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Pediatric organisms

• S. Aureus most common causative organism 5 years
  old
• 25-64 range depending on the age
• Strep infections 4-21
• DOC pcns/cephalosporins
• DOCs are initial txs and should be taylored to
  sensitivities.

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Indications for Surgery

• Aspiration vs. debridement
• Joint does not respond to serial aspirations
• No improvement in 48hrs of tx
• Frank pus is aspirated
• Loculations noted on MRI or U/S
• Documented Hip and SI septic arthritis should be
  debrided surgically
• No change in morbidity between arthroscopic vs.
  arthrotomy of knee

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Surgery

• Hip
• anterior iliofemoral in children
• Adults posteriorlateral approach better drainage?
• Knee
• Arthroscopy vs. Parapatellar approach
• Posteriomedial approach for dependent drainage
• Shoulder
• Arthroscopy vs. deltopectoral
• Wrist
• Dorsal approach between 3rd and 4th compartments
• Elbow
• Posteriolateral
• Close over suction drainage, loose closure
• Splint for 2-3 days until swelling has subsided

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Abx Treatment

• IV abx 4-7 days
• Check CRP,WBC every 2 days
• Once labs normalize and clinically improving
  consider discharge
• Continue tx 2-3 weeks with oral or IV abx (PICC
  line)
• No true standardization of tx
• Get ID involved

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Rehabilitation

• Splinting for 48 hrs
• Salter 1981
• Rabbit knees septic S. aureus
• Had arthrotomy and abx tx
• Casting vs. ROM w/ CPM vs. cage activity
• CPM fared sig. better on pathology of cartilage
  w/ decreased ground substance
• WBAT once rom and pain subsided

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Prognosis and complications

• Poor prognosis factors
• Immunodeficiency, RA, prematurity, osteomyelitis,
  hip, prosthetic infections, blood cultures,
  symptoms 1 week, 4 joints, cultures after
  aspiration after 7 days of abx tx
• Complications
• Mortality 8-15 in three series
• arthritis stiffness, dislocation, subluxation,
  AVN, local growth distrubance, osteomyelitis,
  postinfection synovitis
• Favorable outcome in 50-80 of cases

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The End