osteomyelitis by saccente
DESCRIPTION
Internal Medicine, osteomyelitis resident lectureTRANSCRIPT
Michael Saccente, M.D.
Hematogenous osteomyelitis Contiguous focus osteomyelitis Osteomyelitis associated with peripheral
vascular disease
Waldvogel FA, Medoff G, Swartz MN.N Engl J Med 1970;282:198, 260, 316
Any acute bone infection can become chronic (~ 10 days)
Chronic osteomyelitis is refractory to cure with antibiotics alone
Devitalized bone serves as a nidus for persistent infection (sequestrum)
Compromised soft tissue envelope, draining sinuses
BacteremiaExtension from
contiguous focusAdherence to bone
Acute inflammation
Increased intraosseous pressure andtoxic oxygen radicals, proteolytic enzymes
Vascular congestion and thrombosis
Bone necrosis
Sequestra
Bacterial persistenceLimited host response
Foreign body
Apposition of new bone
Stabilization
Intracellular survival of microorganisms Impaired delivery of host defenses and
antibiotics into dead bone Role of foreign body
Biofilm Local PMN defect Slow growth of surface-adherent bacteria
Hevroni A and Koplewitz B. N Engl J Med 2007;356:e7
An afebrile 8-year-old Ethiopian girl presented with a limp
Lew DP, Waldvogel FA. NEJM 1997; 336: 999-1007
Unusual locations for hematogenous spread Sternoclavicular C- spine Pubic symphysis
Bacteriology similar to infective endocarditis in IDU S. aureus Aerobic GNB- Pseudomonas Others
Gold standard- histopathologic and microbiologic examination of bone
Hematogenous- blood culture (40%) + imaging Extension into joint- fluid culture + imaging Cultures from a chronic draining sinus may be
unreliable (Mackowiak 1978)
Early identification of disease Identify remote sites of disease Define extent of local disease and
complications Assist in surgical plan Should NOT be used alone to make the
diagnosis of osteomyelitis
Plain radiography 99mTc diphosphonate bone scan 111Indium-labeled WBC scan 67Gallium citrate scan CT MRI
Sensitivity (%) Specificity (%)
Bone scanUncomplicatedComplicated
9495
9533
Gallium scan 81 69
In WBC scanGeneralFracturenonunion
8895
8588
MRI 95 88
From Haas DW, McAndrew MP. Am J Med 1996;101:550
SURGICAL MEDICAL
Debridement Hardware removal Obliteration of dead
space Wound protection Restoration of blood
flow Limb stabilization
Optimization of host factors
Specific antimicrobial therapy
There is only limited evidence upon which to base antibiotic selection
No IDSA guidelines exist (though guidelines for diabetic foot infections were published in 2004 and those for prosthetic joint infections in 2013)
Virtually all severe and some moderate infections require parenteral therapy, at least initially
Oral drugs with high oral bioavailability can be used initially in some cases of osteomyelitis
“Standard of care”*- 4 - 6 weeks parenteral for hematogenous (including vertebral) and contiguous
2 weeks parenteral + 4 weeks oral 6 weeks parenteral + > 3 months oral Initial oral quinolones for susceptible
aerobic GNB
*Mader JT, Norden C, Nelson JD, Calandra GB.
Clin Infect Dis 1992;15(suppl 1):S155
Hematogenous Typically 2 bodies and disk Lumbar > thoracic > cervical
Contiguous from Surgery Trauma Visceral source
Manifestations Back pain, fever, tenderness over spine
Complications Instability/Cord Compression
Neurologic complications in 38% of cases in one study (Am J Med 2005;118:1287)
Extension of infection with abscess
Imaging plus culture of Blood 58% (30-78%) Bone 77% (47-100%)
CT-guided or open biopsy Adjacent abscess
Figure 2. MRI of lumbar spine discitis/osteomyelitis. A. Sagittal T1-weighted images of the lumbar spine in the same patient as figure 1 demonstrate T1-hypointense signal (solid arrows) centered around the L3-4 interspace. B. Post gadolinium sagittal fat-
suppressed T1-weighted images shows marrow (dashed arrows) and disc enhancement with endplate erosions.
Vertebral osteomyelitis without abscess can be cured without surgery
No prospective trials Select agent based on in vitro susceptibility
data Duration is usually 6 weeks Usually entire course is intravenous, but switch
to oral FQ is acceptable for a susceptible gram negative
Diagnosis Open biopsy after CT-guided attempts have failed
Relieve cord compression Drain epidural abscess Drain other abscesses when CT-guided
attempts have failed Debridement when medical management has
failed Remove hardware
Skin ulceration or soft tissue infection of foot
Visualize or probe to bone?
Yes No
Presumptive osteo
Plain x-ray
Neg
c/w osteo
Severe peripheral neuropathy
No Yes
High clinical suspicion?
Yes No
WBC or MRI
Suggestive of osteo
Neg
Rx as soft tissue infx,f/u x-ray
Approx mean (range)
Test Sensitivity (%) Specificity (%) PPV (%)
Plain X-ray 60 (28 – 93) 66 (50 –92) 74 – 87
Tc99m bonescan
86 (68 – 100) 45 (0 –79) 43 – 87
In111 WBC 89 (45 –100) 78 (29 –100) 75 – 85
MRI 99 (29 –100) 83 (71 –100) 50 –100
From Lipsky BA. Clin Infect Dis 1997;25:1318
As of 1996, 5 published prospective comparative trials involving 154 patients
Heterogeneous patient types, microbiology, surgical intervention
Debridement obscures the effect of antibiotics Long follow-up
Osteo documented or suspected
Sepsis, plantar abscess, gas in tissues Yes
No
Immediate surgery,cultures,
antibiotics
Assess blood flow, tissue oxygenation, +/- vascular surgery
Not surgical candidate, does not desire surgery
Suppressive antibiotics
Amputation
Perioperative
All infected bone removed
2 weeks
Not all infectedbone removed
4-6 weeks
Definition
Type 1 + intraoperative cultures during revision for what was thought to be a mechanical problem
Type 2 Early postop infection diagnosed within 1 month of index arthroplasty
Type 3 Acute hematogenous infection of a previously well prosthesis
Type 4 Late chronic infection diagnosed > 1 month after index arthroplasty
Prosthetic Joint Infections: Bane of Orthopedists,Challenge for Infectious Disease Specialists
Joseph R. LentinoClinical Infectious Diseases 2003; 36:1157–61
Prosthetic Joint Infections: Bane of Orthopedists,Challenge for Infectious Disease Specialists
Joseph R. LentinoClinical Infectious Diseases 2003; 36:1157–61
Causes of Infection Associated with Prosthetic Joints
Del Pozo J, Patel R. N Engl J Med 2009;361:787-794
Prosthetic Joint Infections: Bane of Orthopedists,Challenge for Infectious Disease Specialists
Joseph R. LentinoClinical Infectious Diseases 2003; 36:1157–61
A radiolucent line along the prosthesis-bone interface suggests loosening
Scanning Electron Micrograph of a Staphylococcus epidermidis Biofilm on Foreign Material. Bacteria grow in multicellular clusters. The scale bar represents 10 microm. (Photograph courtesy of Robin Patel, Mayo Clinic College of Medicine). From: Zimmerli: N Engl J Med, Volume 351(16).October 14, 2004.1645-1654
Bacteria attach to a solid surface When microbial density is high, cell-to-cell signaling
activates the genes involved in the production of glycocalyx (quorum sensing)
The result is a complex community of bacteria that functions almost as a multicellular organism
Individual bacteria within the biofilm enter into a metabolically inactive state
These stationary phase bacteria are resistant to antimicrobial killing and host defenses
Resection with replacement One stage Two stage
Debridement with retention Resection without replacement No surgery
Short duration of symptoms Definitive microbiology Use of an agent which is active against
stationary phase, adherent bacteria (rifampin) No loose implants No MRSA
Small number of patients (safety advisor stopped study after 33 patients were enrolled)
Only 24 patients completed the study Cure rates
12/12 in rifampin group 7/12 in placebo arm
Algorithm for the Treatment of Infection Associated with a Prosthetic Joint
Del Pozo J, Patel R. N Engl J Med 2009;361:787-794