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Bone _ Joint Infections

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					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
   Osteomyelitis
   Septic arthritis
   Infection of prosthetic joints
   Reactive arthritis
                    Sudheer Kher          2
Osteomyelitis
 Infection of bone and medullary cavity
 Tends to recur after treatment
 Classification
   Basis – Anatomy
          » Hematogenous
          » Contiguous focus: with or without
            vascular insufficiency
   Basis – Duration
          » Acute
          » Chronic



                      Sudheer Kher              3
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
   phagocytes.
      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
    ages)
   Streptococcus pyogenes
   Haemophilus influenzae
   Coliforms
   Gp B Streptococci in neonates
    Source – Not always apparent. Usually
    septic focus elsewhere e.g. a boil


                   Sudheer Kher                5
Haematogenous Osteomyelitis

  Adults –
     Usually secondary to distant focus e.g. infected injection site in
     IVDU.
     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
      Coliforms
      Candida sp., Salmonalla sp., Pneumococcus in Sickle Cell Anaemia

                           Sudheer Kher                            6
Contiguous – Focus
Osteomyelitis
 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
      shoes’.
      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.


                        Sudheer Kher                      7
Chronic osteomyelitis
 All forms of osteomyelitis can
 progress to chronicity.
 Presentation –
   Pain, bone destruction, formation of
   sequestrum
   Discharging sinuses, formation of new
   bone : involucrum
   Brodie’s abscess (late, localised
   abscess)
   Involvement of adjacent joints
   Distant spread e.g. endocarditis
                  Sudheer Kher             8
Chronic osteomyelitis

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



                  Sudheer Kher               9
Lab Diagnosis (osteomyelitis)

 Isolation of causal organism & AST
 Cultures
   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
                       Sudheer Kher          10
Lab Diagnosis (osteomyelitis)
   Hematology –
     Acute cases –
      – Polymorphonuclear leukocytosis
      – Raised ESR
      – Raised C-reactive proteins
     Radiology -




                     Sudheer Kher        11
Treatment

 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
                  Sudheer Kher          12
Treatment

        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 /
        Clindamycin)


                         Sudheer Kher                      13
Treatment

     H. influenzae – Ampicillin / Ciprofloxacin
     /Ceftriaxone
     P. aeruginosa – Ciprofloxacin + Gentamicin
     Coliforms, Salmonella - Ciprofloxacin
     /Ceftriaxone
     Anaerobes – Metronidazole or Clindamycin
     Tuberculosis, Brucella, Actinomycosis –
     Specific treatment of the infection.
   Note – Treatment must be continued for
   up to 6 weeks.
                    Sudheer Kher                  14
Septic Arthritis

 Infection of the joint space usually
 seen as
   Complication of septicemia in pre-
   existing joint disease e.g. Rheumatoid
   arthritis
   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
   knee
   Sudden onset, fever, Swelling, redness over
   joint
   Crippling sequelae common
 Causal organsms –
   As in Osteomyelitis, Staph aureus most
   common
   Neisseria gonorrhoeae, N. meningitidis,
                     Sudheer Kher            16
   Mycoplasma hominis, Ureaplasma urealyticum,
Lab Diagnosis (Septic Arthritis)
 Examination of Joint fluid
    Direct Gram film –
        Polymorphs
        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.
 gonorroheae
                             Sudheer Kher                17
Infection in prosthetic joints

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


                  Sudheer Kher      18
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
   bacteraemia
 Causal Organisms – S. aureus, Coagulase
 negative Staphylococci, anerobes.
                       Sudheer Kher                 19
Infection in prosthetic joints

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



                     Sudheer Kher                20
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 +
   Cojunctivitis
                      Sudheer HLA B 27 – 50%
   Predisposing factors –Kher                        21
   patients
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




                     Sudheer Kher                 22

				
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