BONE AND JOINT INFECTIONS

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BONE AND JOINT INFECTIONS

• MICHAEL WHITEHEAD, D.C., D.A.C.B.R

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TERMINOLOGY

• Osteomyelitis
• Infection of bone and marrow
• Septic Arthritis
• Implies a septic process of the joint itself.
• Soft Tissue Infection
• Contamination of cutaneous, subcutaneous,
  tendinous, ligamentous and bursal structures.

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TERMINOLOGY

• Two Types of Osteomyelitis And Septic Arthritis
• Suppurative Osteomyelitis
• Non-suppurative Osteomyelitis

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TERMINOLOGY

• Suppurative Osteomyelitis
• Based on clinical presentation.
• Acute
• Subacute
• Chronic

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RISK FACTORS

• Immunosuppressed Individuals
• Alcoholics
• Newborns
• IV drug users

• Diabetes
• Sickle-Cell
• Post surgical
• Vascular Insufficiency

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MICROORGANISMS

• Suppurative Osteomyelitis
• Staphylococcus aureus (M/C)
• Streptococcus pyogenes
• Streptococcus pneumoniae
• Pseudomonas aeruginosa
• Salmonella
• Haemophilus influenzae

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MICROORGANISMS

• Non-Suppurative Osteomyelitis
• Tuberculosis
• Mycobacterium tuberculosis
• Syphilis
• Treponema pallidum
• Fungal
• Actinomycosis, Coccidioidomycosis

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ROUTES OF CONTAMINATION

• Hematogenous
• Contiguous Source
• Direct Implantation
• Postoperative Infection

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SKELETAL LOCATIONS

• Appendicular skeleton most often affected.
• Femur most common bone involved
• Tibia
• Humerus
• Radius

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CLINICAL MANIFESTATIONS

• M/C age group is 2-12 years of age
• More common in males
• Differences in the clinical and radiographic
  presentation and course of hematologic
  osteomyelitis in the child, infant and adult
  exists

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CLINICAL MANIFESTATIONS

• Childhood and infancy
• Sudden onset of high fever
• Localized pain and swelling
• Chills
• Loss of limb function
• Findings may be less dramatic in the infant

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CLINICAL MANIFESTATIONS

• Adult
• May have a more insidious onset with a longer
  period between the appearance of S/S and the
  diagnosis
• Fever and malaise
• Edema and erythema and pain

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CLINICAL MANIFESTATIONS

• Frequently associated with pre-existing
  infections of other systems
• Genitourinary
• Skin
• Respiratory

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CLINICAL MANIFESTATIONS

• Mainliners Syndrome
• M/C microorganisms are Staphylococcus aureus and
  Pseudomonias
• Other gram-negative organisms
• Frequently involves the S joints.

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LABORATORY FEATURES

• Elevated white cell count
• Schilling shift to the left
• Elevated ESR
• Positive blood cultures with hematogenous (50)

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PATHOLOGIC FEATURES

• Vascular Supply
• Infantile Pattern
• Fetal vascular compartments may persist up to age
  of 1 year
• Vessels may penetrate the physis
• Higher incidence of septic arthritis

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PATHOLOGIC FEATURES

• Vascular Supply
• Childhood Pattern
• 1 year until time open physis fuses
• Epiphyseal supply is separate
• Hematogenous osteomyelitis affects more often the
  metaphysis and not physis or epiphysis

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PATHOLOGIC FEATURES

• Vascular Supply
• Adult Pattern
• Metaphyseal vessels gradually penetrate the
  physis re establishing communication with the
  bone end
• Increased incidence of septic arthritis secondary
  to osteomyelitis

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PATHOPHYSIOLOGY

• Hematogenous Dissemination
• Mechanism
• Usually direct extension from extravascular sites
  of infection ?bloodstream
• Bacteremia

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PATHOPHYSIOLOGY

• Implantation of organism medullary tissue
• Vascular and cellular response
• Active hyperemia?focal osteolysis
• Suppurative edema? intramedullary
  pressure?infarction
• Reaches the subperiosteal space? periosteal
  response

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PATHOPHYSIOLOGY

• Sequestrum
• Necrotic bone due to infarction
• Involucrum
• Bony collar from periosteal new bone
• Cloaca
• Defect in involucrum? discharge
• Most often assoc. with chronic osteomyelitis
• Marjolins ulcer squamous cell carcinoma

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IMAGING FEATURES

• Early Detection
• MRI
• Bone Scintigraphy
• Conventional Radiography
• Latent period Time before osseous changes are
  evident radiographically
• Extremity About 10 days
• Spine About 21 days

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IMAGING FEATURES

• Extremity
• Soft tissue changes are earliest findings
• M/C in the metaphysis
• Moth-eaten or permeative pattern of destruction,
  may see focal osteopenia
• Medullary and cortical destruction
• Periosteal response, Codmans triangle

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IMAGING FEATURES

• Extremity Late Changes
• Sequestration
• Involucrum
• Cloaca
• Sclerosis

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IMAGING FEATURES

• Spine lt20 yoa
• Initial disc involvement ? disc narrowing
• Paraspinal edema, endplate destruction,
  osteolysis
• Spine Adult
• Usually begins vertebral body involves disc
  secondarly
• Vertebrae destruction, collapse, paraspinal
  swelling
• Bony ankylosis may be seen

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BRODIES ABSCESS

• General Comments
• Localized, aborted suppurative osteomyelitis
• Staph aureus m/c
• Often associated with hx of previous infection
• Localized pain worst at night relief by aspirin
• M/C young male children
• Radiographic Features
• M/C metaphysis, distal tibia, prox tibia, fibula,
  dist radius
• Oval, elliptical or serpiginous radiolucency with
  rim of sclerosis

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SEPTIC ARTHRITIS

• General Comments
• M/C below age 30, monoarticular m/c
• Staph aureus m/c
• Restricted ROM, erythema, fever, labs typical
  infection
• M/C knee and hip
• Radiographic Features
• Soft tissue changes in about 3 days
• Loss of subchondral white line, juxta
  periarticular osteopenia, destruction of
  articular ends
• Bony or fibrous ankylosis

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TUBERCULAR SPONDYLITIS

• General Comments
• Radiographic Features