bone and joint infections (and mimics) - amazon web...

© 2012 Virginia Mason Medical Center© 2012 Virginia Mason Medical Center

Bone and Joint Infections (andMimics)

C. Craig Blackmore, MD, MPH, FASERVirginia Mason Medical Center

Seattle, WA


Bone and Joint Infections

• Continuous infection (90%)§ Diabetics§ Trauma§ Iatrogenic

• Hematogenous spread§ Children, elderly§ Immunocompromise, systemic infection§ Intravenous drug use§ MRSA


Osteomyelitis

• Risk factors§ Diabetes RR=5§Male RR=2§ Vascular disease RR=2


Osteomyelitis

Involucrum

Sequestrum


Osteomyelitis

Cloaca


Subacute Osteomyelitis


Chronic Osteomyelitis


Direct Osteomyelitis

• Wounds• Decubitus Ulcers• Diabetic feet


Osteomyelitis


Osteomyelitis• Radiographs/CT§ Normal up to 2 weeks§ Focal osteopenia§ Periosteal new bone formation§ Bone destruction

• MRI§ High STIR signal, edema§ Low T1§ Enhancement


Osteomyelitis

2 weeks later

STIRT1

T1

T1 Gad


Hallux OsteomyelitisT1 Gad

T1 Gad

STIR


Toe Subungal Fracture


Infected Arthroplasty• Radiographs often normal• Subtle (if any) lucencies• Periarticular new bone• Hip/shoulder 1%• Knee 2%


Nuclear Medicine

Courtesy of Paul Sicuro, MD


Pressure Ulcer

• Continued pressure/shear• Elderly, immobile, malnourished• Deep tissues more susceptible than skin§ Underestimate extent of injury

• Bony prominence§ Ischial tuberosity, sacrum, heel, elbow

• Imaging-extent of injury, infection


Decubitus Ulcer


Decubitus Ulcer

• Damage to skin and underlying tissue fromrestricted blood flow due to pressure

• Grade I-IV• Grade IV muscle and bone• Imaging to stage


Decubitus Ulcer

10 months later


Heel Ulcer

2 months later


Amputation


Diabetic Osteomyelitis• 45 yo diabetic male with 1 year non-healing ulcer

STIR

T1 Gad

T1

T1


Diabetic Foot:Accuracy of Imaging

ImagingModality

Source Number ofpatients

Sensitivity(%)

Specificity(%)

Radiography 4 trials 177 54 68

MRI 4 trials 135 90 79

Bone scan 6 trials 185 81 28

Probe tobone

2 trials 288 60 91

Dinh, et al. Clin Infect Dis 2008;299:806-813


Diabetic FootSTIR

T1 GadT1 Gad

T1


Diabetic Foot InfectionsT1 Gad

T1 GadT1

T1


Mimics of Osteomyelitis


Bone Infarct

T1 Gad

T1 Gad

T1


Sickle Cell Anemia


Osteoid Osteoma


Bone Marrow Replacement

62 year old male with leukemia

PD Fat SatT1


Septic Arthritis

• Direct inoculation§ Continuous infection§ Iatrogenic

• Risk factors§ Immunocompromise§ IVDA§ Rheumatoid arthritis§ Diabetes


Septic Arthritis63 yr old female 3 weeks

post prolotherapy

STIR

T1 Gad

T1 Gad


Radiograph Findings

• Early Normal§ Joint effusion§ Osteopenia

• Late§ Focal bone loss§ Bare area erosions§ Collapse subchondral bone


Septic Arthritis

• Imaging (x-ray, CT) NOT sensitive to earlyseptic arthritis


Septic Arthritis


MRI Findings-T1

Low T1 in peri-articular boneConfluent low T1 implies osteomyelitis


MRI Findings-T2/STIR• Joint effusion• High T2 in adjacent bone and soft tissues• Peri-articular bare areas

STIR

T2 Fat Sat


MRI Findings-Contrast

• Thick synovial enhancement• Bare area enhancement

T1 GadT1 Gad


Septic Athritis

62 yr old male, s/p bone marrowtransplant for lymphoma

T1 Gad

T1 Gad


Elbow Septic Bursitis


Osteomyelitis-Septic ArhtritisT1

T1

STIR

STIR


SynovialChondromatosis/Septic Joint

STIR

T1 GadT1 Gad


Mimics of Septic Arthritis


Avascular NecrosisSTIRT1


RheumatoidArthritis

STIR

T1 Gad

T1 Gad


HemophiliaPD Fat Sat

PD Fat Sat

T2 GRE


Pigmented Villonodular SynovitisPD Fat SatPD Fat Sat


Lead Arthropathy


Charcot Joint• Disorganization/subluxation• Fragmentation• NO low T1 in bone• NO enhancement in bone


Charcot vs Osteomyelitis

STIR

T1 Gad


GoutSTIR T1 Gad

T1 Gad

T1 T1 Fat Sat

• Bare area erosions• Overhanging edges• Tophus• NO low T1 in bone


Thank You!

bone and joint infections (and mimics) - amazon web...

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