Term
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Definition
– Infection of the bone
• Can involve the marrow, cortex, and periosteum |
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Term
| Acute osteomyelitis (AOM) |
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Definition
| – Infection present for < 6 weeks |
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Term
| Chronic osteomyelitis (COM) |
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Definition
| – Infection present for > 6 weeks |
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Term
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Definition
– Inflammation in a joint 2° to infection of synovial or periarticular tissue
• Prosthetic joint infection (PJI) |
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Term
| Route of infection Osteomyelitis |
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Definition
– Hematogenous
– Contiguous
– Vascular insufficiency |
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Term
| Osteomyelitis Associated Factors |
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Definition
– Bacteremia
– Trauma
– Surgery
– Orthopedic implants
– Overlying infections
• Diabetic foot ulcerations / infections
– Vascular insufficiency |
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Term
|
Definition
• Bacteremia -> seeding of the bone tissue
– 20% of cases of osteomyelitis in adults
• Infants/children > adults
• Most commonly affects the vertebrae
– Vertebral OM +/- epidural abscess
• Lumbar spine
– May affect other bones
• Long bones, pelvis, clavicle |
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Term
| Osteomyelitis: Contiguous Focus |
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Definition
• Traumatic bone injury /surgery (younger pts)
• Spread from a nearby source (older pts)
• Most common in adults à tibia and femur
• Associated factors
– Surgery
• RIF, prosthetic devices
– Open fractures
– Chronic or regional soft tissue infections
• Decubitus ulcers
– Burns |
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Term
| Osteomyelitis: Vascular Insufficiency |
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Definition
• Impaired blood supply to susceptible tissues
• Usually in older patients 2° to
– Diabetes mellitus
– Severe atherosclerosis
• Predominantly in the small bones of the feet
• OM more likely if ulcer
– Large (>2 cm in diameter)
– Deep (>3 mm)
– Positive probe to bone test
• Bone exposure |
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Term
|
Definition
Onset Less than 6 weeks
Symptoms Fever, chills, malaise
Infection site:
• Pain, limited range of motion, and
redness, warmth or swelling
• May present as septic arthritis
Pathophysiology Hematogenous or contiguous
• IVDU, trauma
• Before development of sequestra
Imaging X-Ray: +/-
MRI: Very sensitive
Bone scan: The sensitivity and specificity varies depending on the appearance
of correlative radiographs. False-positive may occur with noninfectious
changes. False-negative in AOM or in COM with impaired blood flow or
infarction |
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Term
|
Definition
More than 6 weeks
Chronic low-grade fever
Infection site:
• Chronic localized pain, and a draining
sinus tract
• Present for months or even years
Contiguous or vascular insufficiency
• Wounds, injury, DM
• Formation of sequestra / involucrum
• Local bone loss
X-Ray: +
MRI: May overestimate extent/duration
Bone scan: The sensitivity and specificity varies depending on the appearance
of correlative radiographs. False-positive may occur with noninfectious
changes. False-negative in AOM or in COM with impaired blood flow or
infarction |
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Term
|
Definition
Gold standard
– Bacteria from a bone biopsy + histopathology
• Bone biopsy
– Stop antibiotics 48 to 72 hours prior the procedure
• May increase the microbiological yield
• Often positive regardless of prior antibiotic therapy
• Swab, superficial wounds, sinus tracts cultures
and aspiration of material adjacent to the
periosteumà NOT Dx of OM
– Poor correlation with bone biopsy culture results
• Histopathology
– Necrotic bone with extensive resorption adjacent
to an inflammatory exudate
• Laboratory testsà nonspecific
– Leukocytosis
– Elevated ESR/CRP
• May be normal
– Blood cultures
• Positive in 50% of AOM cases
– Isolated organism likely cause of OM |
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Term
|
Definition
• No official guidelines for OM
– Guidelines available
• PJI
• Diabetic foot infections
• Acute OM “easier” to treat vs. chronic OM
• Historically IV antibiotics used
– More published data on PO than IV
• Show similar outcomes
• Duration
– 4-6 weeks (or longer)
• CULTURES BEFORE ABX !!!!
– If blood cx positive
• No need for invasive cxà assume the same organism
– If blood cx negative
• Need bone cx
• DO NOT culture sinus tract drainage
– Not predictive of bone cx
• No empiric therapy for
– Chronic OM
– Vascular insufficiency
• Unless acutely ill |
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Term
Extremity OM Etiologies
(Usual) |
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Definition
|
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Term
|
Definition
MRSA possible:
Vancomycin
MRSA not possible:Nafcillin /Oxacillin(Clindamycin, TMP-SMX,Linezolid*)
• Cx prior to ABX, micro diagnosis is essential
• If Gram stain GNR add cefepime or ceftazidime |
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Term
|
Definition
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Term
|
Definition
MRSA possible: Vancomycin
MRSA not possible Nafcillin/Oxacillin
MRI to evaluate for epidural abscess |
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Term
Sickle Cell /
thalassemia Etiologies
(Usual) |
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Definition
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Term
Sickle Cell /
thalassemia Treatment |
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Definition
Ciprofloxacin (+/- 3rd gen ceph)
Levofloxacin (+/- 3rd gen ceph)
Increased resistance to FQ |
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Term
| OM secondary to nail through tennis shoe Etiologies |
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Definition
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Term
| OM secondary to nail through tennis shoe Treatment |
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Definition
Ciprofloxacin or Levofloxacin
Cefepime or Ceftazidime
• OM in 1-2% of plantar puncture wounds
• If no OM, debridement and removal of foreign body, no ABX
• Tetanus prophylaxis |
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Term
| OM of long bone postinternal fixation of fracture Etiologies |
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Definition
| S. aureus,GNR, P.aeruginosa |
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Term
| OM of long bone postinternal fixation of fracture Treatment |
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Definition
Vancomycin + Cefepime or Ceftazidime
Linezolid,Clindamycin,TMP-SMX + Cefepime or Ceftazidime
• May need hardware removal and revascularization |
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Term
Contiguous w/ Vascular
Insufficiency: Empiric |
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Definition
• Most patients will have DM
• Polymicrobial
– No empiric therapy
• Unless acutely ill
– Treatment based on cultures
• Revascularization if possible
• Chronic OM
– No empiric therapy |
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Term
| Septic Arthritis: Pathophysiology |
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Definition
• Hematogenous spread to the bone
– Most common
• Bites / trauma
• Direct inoculation of bacteria
– Surgery
• Spread from adjacent infected bone
– Rare
• Bacterial infection most common
– Fungal
– Mycobacterial |
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Term
| Septic Arthritis: Associated Factors |
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Definition
• Age > 80 years old
• DM
• Rheumatoid arthritis (RA)
• Recent joint surgery
• Prosthetic joint
• Skin infection, cutaneous ulcers
• Previous intra-articular corticosteroid injection
• IV drug abuse, alcoholism |
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Term
| Septic Arthritis: Nongonococcal |
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Definition
• Clinical Presentation
– Acute
– Monoarticular
• 20% of cases are oligoartiular or polyarticular
– 2 or 3 joints
– Patients with RA or overwhelming sepsis
– Knee, wrist, ankle and hips
• IVDU: sternoclavicular or sternomanubrial
– Joint pain, swelling, restricted movement
– Fevers
• Elderly persons are more likely to be afebrile |
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Term
| Septic Arthritis: Diagnosis |
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Definition
• Identification of bacteria from synovial fluid
– Synovial fluid aspiration
• Gram stain
• Culture
• Leukocyte count and differential
• Blood cultures
– Positive in 50% of patients
• CBC with differential
• ESR, CRP
Synovial fluid culture
– Positive in majority of patients with nongonococcal
septic arthritis
– Negative cultures can occur
• Recent antibiotics
• Fastidious organisms (Mycoplasma spp., some
streptococci)
• Gram stain
– Often positive (not always)
– False positive
• Precipitated crystal violet and mucin à GPC |
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Term
| Septic Arthritis: Treatment |
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Definition
• Antimicrobial choice is based on
– Most likely cause
– Clinical presentation
– Gram stain
• Gram stain with GPC
– Vancomycin
• Gram stain with GNR
– 3rd generation cephalosporin or anti-PSA β-
lactam (if PSA suspected)
• Ciprofloxacin if allergy
• Gram stain negative
– Immunocompetent
• Vancomycin
– Immunocompromised, IVDU
• Vancomycin + 3rd generation cephalosporin or anti-
PSA β-lactam (if PSA suspected)
– Ciprofloxacin if allergy
• Modify antibiotics based on culture results
• Durationà No randomized trials
– IV X 14 days followed by PO 14 days
• Longer IV for bacteremia and certain pathogens |
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Term
| Septic Arthritis: Gonococcal |
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Definition
• Most common cause of septic arthritis
• One of the manifestations of disseminated
gonococcal infection (DGI)
– N. gonorrhoeae
• Untreated mucosal infection
• Asymptomatic infection
• Usually 1 or 2 large joints are affected
– Most commonly knees, wrists, ankles, elbows
– Joints are hot, painful, swollen with restricted movement |
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Term
|
Definition
• Treatment
– Ceftriaxone 1g IV q24 hrs X 7 -14 days
• Up to 21 days
– Joint drainage
– Concurrent treatment for Chlamydia
• Doxycycline 100mg PO BID X 7 days
– Sex partner to be referred for
• Evaluation and treatment |
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Term
|
Definition
• Sinus tract that communicates with the
prosthesis
• Purulence without another known etiology
surrounding the prosthesis
• 2 or more intraoperative cultures or
preoperative aspiration and intraoperative
culture that grows the same organism
– Growth of a virulent organism (S. aureus) in one
specimen can represent PJI |
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Term
|
Definition
• Almost always: surgery + prolonged ABX
• Preoperative
– ESR and CRP
– Blood cultures
• If febrile or acute onset of symptoms
– Diagnostic arthrocentesis
• If possible withhold antibiotics for 2 weeks prior
• Intraoperative
– At least 3 sets of cultures, optimally 5 or 6 tissue
samples for cultures or prosthesis itself
– If possible hold antibiotics for 2 weeks prior
• Surgical options
– Debridement and retention of prosthesis
• Well-fixed prosthesis, no sinus tract, within 30 days
of implantation or < 3 weeks of symptoms
– 2 stage exchange
• Most common in US
– 1 stage exchange
• May be greater risk of failure
– Permanent resection arthroplasty
– Amputation |
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Term
|
Definition
• Total 3 months of pathogen-specific therapy
– Total hip arthroplasty (THA)
– Total elbow arthroplasty
– Total shoulder arthroplasty
– Total ankle arthroplasty
• Total 6 months of pathogen-specific therapy
– Total knee arthroplasty (TKA)
• 2-6 weeks of IV antibiotics + rifampin
– Followed by PO antibiotic + rifampin
• If rifampin cannot be used
– 4-6 weeks of IV antibiotics
• For chronic suppression evaluate
– Ability to use rifampin in the initial treatment
– Progressive implant loosening
– Loss of bone stock
– Risk of prolonged antibiotics
– Generally reserved for patients
• Unsuitable / refuse further exchange revision, excision arthroplasty or amputation |
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Term
|
Definition
• Total 3 months of pathogen-specific therapy
– Total hip arthroplasty (THA)
– Total elbow arthroplasty
– Total shoulder arthroplasty
– Total ankle arthroplasty
• Total 6 months of pathogen-specific therapy
– Total knee arthroplasty (TKA)
• 2-6 weeks of IV antibiotics + rifampin
– Followed by PO antibiotic + rifampin
• If rifampin cannot be used
– 4-6 weeks of IV antibiotics
• For chronic suppression evaluate
– Ability to use rifampin in the initial treatment
– Progressive implant loosening
– Loss of bone stock
– Risk of prolonged antibiotics
– Generally reserved for patients
• Unsuitable / refuse further exchange revision,
excision arthroplasty or amputation. |
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Term
| PJI due to other organisms |
|
Definition
• 4 – 6 weeks of pathogen-specific antibiotics
– IV or PO (if with good bioavailability)
• May consider chronic suppression therapy
– After initial therapy and not candidate for further
surgery
– Not unanimously recommended if FQ are used as
initial therapy for GNR infections |
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Term
RESECTION ARTHROPLASTY WITH OR WITHOUT
REIMPLANTATION Management |
|
Definition
• 4 – 6 weeks of pathogen-specific antibiotics
– IV or PO (with good bioavailability)
• Medical treatment following amputation
– 24 to 48 hours of pathogen-specific antibiotics
after amputation
• All infected tissue has been surgically removed
• No concomitant sepsis or bacteremia
– Concomitant sepsis or bacteremia
• Treatment duration based on those specific syndromes |
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