department of radiology. institut m t kassab d’orthopédie. ksar said. tunisia ultrasound of...
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Department of Radiology. Institut M T Kassab d’orthopédie. Ksar Said. Tunisia
ULTRASOUND OF MUSCULOSKELETAL INFECTIONS
MA KAMMOUN, M CHELLI BOUAZIZ, A MAALEJ, M F LADEB
MUSCULOSKELETAL : MK 23
INTRODUCTION
• Musculoskeletal infections are commonly encountered in clinical practice in children and adult patients
• Radiographs remain the first imaging modality to perform in these conditions
• Ultrasound (US) may be used either as the primary imaging technique or as an adjunct to radiography, computed tomography (CT), magnetic resonance imaging (MRI) and nuclear medicine studies
OSTEOMYELITIS
Acute osteomyelitis
•Daily US examination allows an early detection of subperiosteal
abcess thus indicating surgical treatment (protocol of Tunis).
•Clinical and US differential diagnosis is sometimes difficult with
sickle cell anemia vaso-occusive crisis and subperiosteal
haematoma.
Acute osteomyelitis: subperiosteal abcess of the femur is well assessed with US
Acute osteomyelitis: subperiosteal abcess of the tibia is well assessed with US
Vaso-occlusive crisis. US shows a subperiosteal haematoma of the tibia
Vaso-occlusive crisis. US shows a subperiosteal haematoma
OSTEOMYELITIS
Chronic osteomyelitis
• Soft tissue modifications and /or Juxtacortical collections are
assessed with US in acute reactivation of chronic osteomyelitis.
• Fistula , soft tissue sequestra and cortical bone modifications are
also well assessed with US
Chronic osteomyelitis reactivation: Juxtacortical abcess with sequestrum
*
Chronic osteomyelitis reactivation:
Juxtacortical abcess with a fistula.(*)
*
Reactivation of a chronic osteomyelitis. US shows cortical bone irregularities and calcifiactions with a soft tissue abcess
ARTHRITIS
• In acute arthritis, US shows a joint effusion with or
without synovial thickening and local hyperhemia.
• Bone abnormalities such as periosteal new bone
formation or perichondral erosions are also well
assessed by US
ARTHRITIS
• Chronic arthritis may show a similar appearance
• A local amyotrophy around the joint may be observed.
Several ultrasonographic signs may help to identify
specific infections
ARTHRITIS
• The importance of synovial thickening and the
presence of thin calcifications into the synovium
suggests a tuberculous origin whereas a multicystic
appearance is characteristic of echinococcosis
Acute knee arthritis. US shows a joint effusion with synovial thickening
Acute arthritis of the elbow. US Shows a joint effusion without synovial thickening
Acute arthritis of the knee. US shows an important synovial thickening with joint effusion and local
hyperhemia.
Osteo arthritis of the first metatarsophlangeal joint. Bone abnormalities such as periosteal new bone formation (*) and perichondral bone erosion (**) are easily assessed by US
* **
Tuberculous arthritis of the knee. Note the importance of the synovial thickening and the fine synovial calcification(*).
*
Echinococcosis of the iliac bone. US shows a characteristic multicystic appearance in the soft tissues.
INFECTIOUS CELLULITIS
• Infection of the skin and subcutaneous tissue
• Clinical diagnosis often obvious:
• Sudden onset of local and general
inflammatory closet "orange peel“
• Alteration of general state, fever, ganglia
INFECTIOUS CELLULITIS IMAGING
• Radiographs: nonspecific
• Ultrasound: abscessDiffuse thickening of the skin"dissected appearance" of subcutaneous fat lobulesHyperemia at color Doppler
• CT / MRI:Infiltration of subcutaneous fatHypo T1, T2 Hyper without mass effectEnhancement after contrast injection+ / - Edema of the fascia and adjacent muscles
Radiographs showing thikening
of sucutaneous fat (*).
*
US: soft tissue thickening and Doppler hyperhaemia
soft tissue cellulitis: US shows "dissected appearance" of subcutaneous fat lobules
PHLEGMON AND PYOMYOSITIS
• Pyomyositis: muscle abscess
• Phlegmon: inflammatory infiltration of the muscle not collected before the collected stage
PHLEGMON AND PYOMYOSITISCLINICAL PRESENTATION
• Pain
• Muscle induration
• History of local trauma: from 22 to 67%
• A single muscle group is usually affected
• Careful analysis of adjacent bones and joints to confirm the muscular origin of the infection
PHLEGMON AND PYOMYOSITISIMAGING
• Radiographs : of little use
• Ultrasound:Increased muscle volumehypoechoic septaEvolution towards the abscess with hypoechoic center + / - standard liquid or thin wallsEchogenic wall + / - thick that may contain calcificationsImaging can guide the puncture
Pyomyositis of the thigh: US shows muscle thickening, heterogenous appearance
and colour Doppler hyperhemia.
Pyo-myositis in 33 years old man. US shows global thikening of biceps muscle and
presence of liquid collection (abcess) into the muscle.
SEPTIC BURSITIS• Clinical presentation: local inflammatory syndrome
Fever: 40% of cases
• Germ: staph aureus
• X-rays + CT: Swelling of the bursa
• Ultrasound: Thickening of the bursa wall, echogenic content , Doppler
hyperemia
• MRI: staging
Septic bursitis: Ultrasound shows
thickening of the subacromial subdeltoid
bursa wall with color Doppler
hyperemia and fluid collection
SEPTIC TENOSYNOVITIS
• Often by inoculation
• Staph aureus, tuberculosis
• Fingers and toes flexors
• Radiographs: eliminate arthritis or osteitis
• Ultrasound: thickening of tendon sheath + / - effusion, Doppler hyperemia
• MRI: thickening of tendon sheath, enhancement after contrast injection
Tenosynovitis: US shows thickening of the tendon sheath + / - effusion, Doppler hyperhemia Note also the presence of little abcesses into the synovial sheath
CONCLUSION
• Ultrasound is very performant in the diagnosis and follow up of musculoskeletal infections.
• It allows to:
• differentiate infection from tumors or non-infective inflammatory conditions with similar clinical presentation
• localize the site and extent of infection
• guide drainage or biopsy