Bone _ Joint Infections

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Bone _ Joint Infections Powered By Docstoc
					Bone & Joint Infections

                Dr. Sudheer Kher
                   Prof & Head
               Dept of Microbiology
         Gulf Medical College, Ajman, UAE
Infections of the bones & joints
 Both children and adults are affected.
 Delay and inadequate treatment can
 result in protracted illness &
 permanent disability.
 Four main diseases are
   Septic arthritis
   Infection of prosthetic joints
   Reactive arthritis
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 Infection of bone and medullary cavity
 Tends to recur after treatment
   Basis – Anatomy
          » Hematogenous
          » Contiguous focus: with or without
            vascular insufficiency
   Basis – Duration
          » Acute
          » Chronic

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Haematogenous Osteomyelitis
 Clinical features –
   Children – Usually under 10 Y age, present
   with acute metaphyseal disease. This region is
   ideal bacterial ‘seeding’ area: unusual end-
   artery capillary system forming venous
   sinusoids of slow-moving blood lacking in
      Classical sites – Distal femur, Proximal tibia and
      proximal humerous.
      Presentation – Bone pain, fever, local tenderness.
      The child is reluctant to move the limb. History of
      previos trauma may be there. Neonates may not have
      no localizing signs.
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Haematogenous Osteomyelitis
    Causal organism –
   Staphylococcus aureus (Most common in all
   Streptococcus pyogenes
   Haemophilus influenzae
   Gp B Streptococci in neonates
    Source – Not always apparent. Usually
    septic focus elsewhere e.g. a boil

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Haematogenous Osteomyelitis

  Adults –
     Usually secondary to distant focus e.g. infected injection site in
     Commonly affected sites –
        Most common - Vertebrae
        Long bones – Diaphysis
        In IVDU – Pubic & Clavicular bones often extending into joint cavity.
     Presentation – Often non-specific pain and vague symptoms, but
     can present with acute site specific symptoms.
     Causal organisms –
      Staphylococcus aureus (Most common)
      Ps. aeruginosa
      Streptococcus pyogenes
      Haemophilus influenzae
      Candida sp., Salmonalla sp., Pneumococcus in Sickle Cell Anaemia

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Contiguous – Focus
 Infection at any age may follow direct
 contamination of exposed bones.
   Without vascular insufficiency –
      After major trauma (compound fracture)
      Animal & human bites (Clenched-fist injury)
      Puncture wound to calcaneum through soft ‘training
      Extension of septic arthritis.
      Orthopedic surgocal infections: may be device related
      e.g. fixator sites.
      Causal organisms- S. aureus (usually MRSA),
      coliforms, streptococci and anaerobes.

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Chronic osteomyelitis
 All forms of osteomyelitis can
 progress to chronicity.
 Presentation –
   Pain, bone destruction, formation of
   Discharging sinuses, formation of new
   bone : involucrum
   Brodie’s abscess (late, localised
   Involvement of adjacent joints
   Distant spread e.g. endocarditis
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Chronic osteomyelitis

 Causal organisms –
   In addition to listed organisms,
   uncommon causes like
   M. tuberculosis
   Brucella spp.
   Actinomycosis (usually involving dental

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Lab Diagnosis (osteomyelitis)

 Isolation of causal organism & AST
   Blood cultures – Positive in many
   hematogenous cases. Several cultures
   may be necessary.
   Pus –
     Collected from diseased bone
      – Needle aspiration
      – Bone biopsy at open operation
      – Pus from sinus tract is unreliable
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Lab Diagnosis (osteomyelitis)
   Hematology –
     Acute cases –
      – Polymorphonuclear leukocytosis
      – Raised ESR
      – Raised C-reactive proteins
     Radiology -

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 General – Antibiotic therapy.
 Empirical for Staph. aureus
 (flucloxacillin) + Gentamicin if GNB
 infection suspected.
 Surgery –
   To drain pus
   Remove sequestrum
   Obliterate dead space
   Restore vascular supply
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        Orthopedic procedures
         – Bone grafting
         – Stabilization of fractures
   Specific treatment
     Antibiotic choice –
        Basis – Bactericidal activity, Bone penetration, Route of
        administration (initially parenteral; later switch to oral)
        S. aureus – Flucloxacillin + either Gentamicin / Clindamycin /
        Fusidic acid / Rifampicin
        MRSA strains – Vancomycin + Fusidic acid / Rifampicin
        Streptococci (Gp A, B or Pneumococci – Penicillin /

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     H. influenzae – Ampicillin / Ciprofloxacin
     P. aeruginosa – Ciprofloxacin + Gentamicin
     Coliforms, Salmonella - Ciprofloxacin
     Anaerobes – Metronidazole or Clindamycin
     Tuberculosis, Brucella, Actinomycosis –
     Specific treatment of the infection.
   Note – Treatment must be continued for
   up to 6 weeks.
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Septic Arthritis

 Infection of the joint space usually
 seen as
   Complication of septicemia in pre-
   existing joint disease e.g. Rheumatoid
   An extension of osteomyelitis
   Infection following intra-articular
   injection, arthroscopy or orthopedic
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   surgery especially insertion of joint
Septic Arthritis
 Clinical Features –
   Severe pain leading to restriction of movement
   Generally single joint involvement – particularly
   Sudden onset, fever, Swelling, redness over
   Crippling sequelae common
 Causal organsms –
   As in Osteomyelitis, Staph aureus most
   Neisseria gonorrhoeae, N. meningitidis,
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   Mycoplasma hominis, Ureaplasma urealyticum,
Lab Diagnosis (Septic Arthritis)
 Examination of Joint fluid
    Direct Gram film –
        Bacteria – Presumptive diagnosis & treatment
        Culture – Variety of media for causal organsim
 Blood Cuture – Positive in 30-60% cases
 Culture of specimens from other infected sites –
    Throat / Genital tract / Meninges
    Sputum/urine in suspected tuberculosis
 Serological tests in Brucellosis / Lyme Disease
 Molecular Methods for detecting Bacterial DNA in
 synovial fluid e.g. B. burgdorferi, M. hominis, N.
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Infection in prosthetic joints

 Often organisms of low pathogenecity
 can infect.
 Risk factors –
   Rheumatoid arthritis
   Diabetes mellitus

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Infection in prosthetic joints
 Clinical features –
   Early fulminant, with hematoma or wound
   sepsis, usually within a month of operation
   Delayed indolent low grade painful infection,
   within one year of surgery
  Source of Infection – Operation site Patient’s skin
   / Surgical team / Contact / Theatre air
   Late onset septic arthritis –(usually after 2
   years) caused by organisms settling in the
   implant from a transient asymptomatic
 Causal Organisms – S. aureus, Coagulase
 negative Staphylococci, anerobes.
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Infection in prosthetic joints

 Lab diagnosis –
   Often impossible due to difficulty in accessing
   Culture – Perioperative surgical tissue.
   Culture of sinus track or superficial wound is
   not recommended.
   Hematology – ESR & CRP usually elevated

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Reactive Arthritis
 Acute arthritis affecting one or more joints
 which develops 1-4 weeks after infection of
 genital or gastrointestinal tracts.
 Caused due to immunological mechanism.
 Joint exudate is sterile.
 Forms of reactive arthritis
   Post-sexual reactive arthritis – Arthritis + ocular
   inflammation (Conjunctivitis / Iritis) post non-
   gonoccal urethritis - Often caused by
   Chlamydia trachmatis. Almost exclusively seen
   in men.
   Reiter’s sundrome – Arthritis + Urethritis +
                      Sudheer HLA B 27 – 50%
   Predisposing factors –Kher                        21
Reactive Arthritis
     Post-dysenteric reactive arthritis – Arthritis
     presents after Gastrointestinal infection with
     Gram-negative bacilli such as shigella,
     salmonella, campylobacter, yersinia. Affects
     both men & women. Urethritis and
     conjunctivitis common features

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