ETIOLOGY

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ETIOLOGY

• acute hematogenous osteomyelitis
• subacute osteomyelitis
• chronic osteomyelitis

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osteomyelitis

• Osteomyelitis may occur at any age.
• Most common in ages 3-12 years.
• It affected boys twice frequently as girls .
• A microbial ethiology is confirmed in three
  fourth of osteomyelitis and two thirds of cases
  of septic joint

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pathogenesis

• Hematogenous
• Direct spread from a contiguous focus of
  infection.
• Osteomylitis in children is most often the
  consequence of bacterremia.

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Pathogenesis (con)

• involves growing bone . Particularly the
  metaphyses of the long bone .
• Femur and tibia are equally and together almost
  half of the all cases .
• (distal femur , proximal tibia ,distal humerus
  , distal radius)

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Pathogenesis (con)

• Bacteria lodge in nutrient arteries supplying the
  growth plates of bones.
• Blood in the large sinusoidal veins flows slowly
• No phagocytic cells present in this area.
• Obstruction of flow by bacterial microemboli
  produces small areas of avascular necrosis and
  metaphyseal abscess .

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• Bacteria lodge in nutrient arteries supplying the
  growth plates of bones.
• Blood in the large sinusoidal veins flows slowly.
• No phagocytic cells present in this area.
• 3. bstruction of flow by bacterial microemboli
  produces small areas of avascular necrosis and
  metaphyseal abscess .

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pathogenesis
(con)

• Trauma often is noted before the onset of
  osteomyelitis. (in about one third)
• In infantlt1 yr the capillaries perforate the
  epiphyseal growth plate .
• Spread across the epiphysis ,which causes a
  septic arthritis .

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pathogenesis (con)

• Pyartheritis complicating osteomyelitis is
  common in joints
• that capsule inserts to the metaphysis proximal
  to the epiphyseal plate .
• ( hip, elbow, shoulder , knee)

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capsule inserts to the metaphysis proximal to
the epiphyseal plate . ( hip, elbow, shoulder ,
knee)
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Chronic osteomyelitis

• Involucrum
• Infected periosteum calcify into a shell of
  new bone around the infected portion of the
  shaft .
• Brodie abscess a subacute intraosseous
• abscess that does not drain into the
  subperiosteal space and is classically located in
  the distal tibia
• Sequestrum portions of avascular bone that have
  separated from adjacent bone, frequenrly are
  covered with a thickened sheat

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Contiguous osteomyelitis

• Less common in children
• Usually occur after the spread of cellulitis as
  a result of Infected wound .
• osteomyelitis also may result from direct
  inoculation of a penetrating wound
• Primary viral infection of bones or joints
  are rare

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etiology

• S.aureus is responsible for most infections in
  all age groups.
• Group B ( neonate) or other streptococci(A) and
  pneumococcus , anaerobic microorganism ,
  gram-negative entric bacteria, M,tuberculosis .
• furunculosis , infected burns ,varicella,
  trauma,
• drug abuse ,prolong IV or central parenteral
  alimentation

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etiology

• Sickle cell anemia
• ( salmonella , staphylococcus and less common
  S.pneumonia)
• Cat or dog bite ( pasteurella multocida)
• Puncture wounds ,IV drug abuse (pseudomonas)
• H,influ type b account for more than half of all
  case but is rarely seen in an immunized
  population .

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Clinical manifestations

• Hematogenous osteomylitis usually involves a
  single bone.
• The most common presenting complaints are focal
  pain, exquisite point tenderness over the bone,
  warmth, erythema, swelling, and decreased use of
  the affected extremity.
• Fever, anorexia, irritability, and lethargy may
  accompany the focal findings.

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Clinical manifestations

• Weight bearing and spontaneous or requested
  motion are refused .( pseudoparalysis)
• Hematogenous vertebral osteomyelitis is insidious
  onset. With little fever or systemic toxicity.
• Pelvic osteomyelitis present with limp
  ,abdominal, hip ,groin ,pain and fever

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Clinical manifestations

• Neonate 40 multiple site local edema
  GBS,E coli
• 
  reduced limb motion
  S,aureus
• 
  joint effusion (60-70)
• 1-24 mo long bones
  pseudoparalysis
  S,aureus
• involve joints
  fever,limp
  GBS
• 2-20 yr metaphysis of focal pain
  fever (90) S,aureus(60-90)
• long bones
  focal tenderness (70) strep(10)
• rarely vertebral
  joint effusion (20)
• pelvis

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diagnosis

• Marked tenderness over the involved site.
• leukocytosis may be present , ESR ?, CRP ?
• Blood culture ( 60 positive).
• Cultures of aspirated cellulitis or priosteal
  space before antibiotic therapy.

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diagnosis

• Radiography
• finding of acute systemic osteomyelitis, at about
  9 days, is loss of the periosteal fat line
• Periosteal elevation and periosteal destruction
  are later findings
• technetium 99m bone scans .
• MRI is particularly useful for extended of
  infection or when infection is a complication of
  trauma , surgery, sickle cell anemia

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treatment

• Initial IV antibiotic should be based on result
  of Gram stain of bone aspiration ,blood culture,
  age associated disease.
• Initial IV antibiotic should cover S.aureus
• (oxacillin,nafcillin methicillin,
  clindamycin)
• Possibility of methicilin resistant staph
  should be considered .
• Gram- negative organism if wound contamination or
  IV drug abuse .

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treatment ( con)

• sickle cell anemia S.aureus and salmonell must
  be covered (cefotaxim ,ceftriaxon)
• The response to appropriate IV antibiotic
  usually occur in 48 hr .
• Lack of improvement in fever and pain after this
  time indicates that surgical drainage may be
  necessary or an unusual pathogen may be present .

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Treatment ( con)

• surgical drainage may be appropriate at earlier
  time if
• sequestrum is present
• disease is chronic or atypical
• the hip joint is involved
• Presence of spinal cord compression.
• standard therapy usually consist of antibiotic
  for 4-6 weeks

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• After initial inpatient treatment and a good
  clinical response, including decreases in CRP or
  ESR, consideration may be given for home therapy
  with IV antibiotics or oral antibiotics,

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Septic Arthritis

• It occurs most commonly during the first 2 yr of
  life and adolescence.
• Half of all cases occur by 2 yr and three fourths
  occur by 5 yr .
• Joints of the lower extremity constitute three
  fourth of all cases.

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pathogenesis

• Hematogenous dissemination of bacteria.
• Contaguous spread from surrrounding tissues.
• Spread of osteomyelitis through the epiphysis
  into the joint space in young children .
• Presenting in the first 3 days more often
  represent the hamatogenous spread of bacteria .

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pathogenesis

• Post infectious joint effusion
• Which is sterile .
• caused by antigen- antibody complex.
• Developed after 7 days of bacterial illness.
• ( bacteremia, meningitis, diarrhea , urethritis)

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etiology

• S.aureus is the most common agent.
• H.influ type b is the most common factor in 3
  month to -4 yr .
• Streptococci , pneumococci, meningococci that may
  occure in the absence of sepsis or meningitis.
• Gonococcal arthritis most common cause of
  polyartheritis and monoarticular artheritis in
  adolecent.

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Clinical manifestation

• Erythema , warmth , swelling, and tenderness with
  a palpable effusion and decreased range of
  movement . Toddlers demonstrate a limp .
• Acute septic arthritis most often involves a
  single joint .
• Multiple joints in 10 .
• The onset may be sudden with fever and chills
• Insidious with symptoms noted only when the joint
  is moved .

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Clinical manifestation( con)

• Often difficult to assess septic arthritis of the
  hip and may cause referred pain the knee .
• The hip for minimize pain from pressure ,The
  limb may be positioned in external rotation and
  flexion .
• The knee and elbow joints usually are in flexion .

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diagnosis

• Leukocytosis , elevated ESR or CRP are common .
• Arthrocentesis is the test of choice for rapid
  diagnosis .
• Blood or joint cultures are positive in 70up to
  85 in cases
• ultraSonography is helpful in detecting joint
  effusion and may guide localization for
  aspiration .

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• Plain radiographs typically add little
  information to the physical findings.
• Radiographs may show swelling
• of the joint capsule, a widened joint space,
  and displacement of adjacent normal fat lines.

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• Radionuclide scans are of limited use, although
  technetium-99m
• bone scans may be helpful to exclude concurrent
  bone infection, eithir adjacint or distant from
  the infected
• joint.

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• MRI is useful in distinguishing joint infections
  from cellulitis or deep abscesses.

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diagnosis (Synovial fluid analysis)

• Synovial fluid analysisfor cell count, diff
  ,protein and glucose has limited usefulness .
• Noninfection inflammatory disease can also
  increased cells and protein and decreased glucose
• (rheumatic fever , and rheumatoid arthritis)

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diagnosis

• In up to 30 of patients who have never received
  antibiotic may not reveal bacterial pathogens .
• In chronic arthritis synovial biopsy may
  distinguish between an septic and a non infection
  process.
• Radiography or bone scans of adjacent bone .

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Differential diagnosis

• Reactive arthritis is immune-mediated synovial
  inflammation thar follows a bacrerial or viral
  infection
• Non infectious
• (Rheumatoid arthritis , SLE,serum sickness , IBD)
• Henoch schonlein purpura, leukemia ,metabolic
  diseases , foreign bodies , traumatic arthritis
• viral infections may cause arthritis

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• Suppurative arthritis must be distinguished from
  Lyme disease, osteomyelitis, suppurative
  bursitis, fasciitis, myositis, cellulitis, and
  soft tissue abscesses.
• Psoas muscle abscess often presents with fever
  and pain on hip flexion and rotation

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Differential diagnosis

• Toxic tenosynovitis of the hip
• Common condition of children age 3-6 years .
• May be viral in etiology .
• Selflimited disorder and more common than septic
  arthritis .
• bacterial infections (TB, syphilis.Lyme disease)

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treatment

• Therapy is based on
• Likely organism
• Gramstain of joint fluid
• host immunologic status
• Parenteral antimicrobial agents.
• Surgical intervention reserved for specific
  situation.

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treatment (CON)

• Pyogenic arthritis of the hip or shoulder caused
  by S.aureus usually necessiatates prompt
  surgical drainage.
• Staphylococcal infection of the knee may be
  treated with repeated arthrocenteses and
  countinuation of appropriate IV antibiotics

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treatment (CON)

• For empirical therapy
• in the neonate antibiotic against
  staphyloccocci, GBS, and aerobic gram- negative.
• ( cefotaxim or ticarcillin / clavulanate)
• Infant 3 month- 4 years antibiotic against
• S. aureus and H .influ type b until culture
  results are known .
• ( cefotaxim or ampicillin /sulbactam)

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treatment (CON)

• IV meticillin is the choice for S.aureus .
• Vancomycin for methicillin- resistant .
• The length of therapy depends on
• Clinical resolation
• reduction of ESR .
• S.Aureus 14-21 days or more .
• Gonococcal or meningococcal 7 days of penicillin

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treatment (CON)

• Oral agents against s.aureus are
• augmentin.cloxacillin , dicloxacillin ,
  cephalexin , clindamycin, and ciprofloxacin
  these are often used to complete therapy .