Septic arthritis radiology

4. Causes :
• Bacterial (staphylococcus aureus, E.coli, proteus and
streptococcus)
• viral
• mycobacterial
• fungal

5. Predisposing factors:
 Rheumatoid arthritis
 Intravenous drug abuse
 Immunosuppressive drug therapy
 AIDS
 DM
 Old age >80 years
 Chronic disorder

7. Hematogenous spread
 Most common form of spread
 Usually affect people with underlying medical
problem
Direct inoculation
• May result from penetrating trauma
• Introduction of organism during diagnostic and
surgical procedure e.g. arthroscopy and intra-articular
injection
Direct spread from adjacent focal infection

10. Clinical manifestations
 Fever
 Acute severe pain
 Swelling of the joint
 Tenderness
 Warmth
 Limited joint mobility

11. Imaging:
X-RAY:
 Early stage –soft tissue swelling, loss of tissue planes,
widening of joint space and slight sublaxation due to
fluid in the joint.
 Gas may be seen with E.coli infection
 Late stage – narrowing and irregularity of joint space
 Periosteal reaction, bone destruction and
sequestrum formation

13. Lateral view of ankle joint, exaggerated soft tissue swelling,
decreased joint space with sclerotic ends of bone

14. Underlying bony erosions and reduced joint space in
talus AP view

15. Joint space
decreased
osteophytes AP view

16. Head of femur deformed and
necrosed,loss of joint space LEFT SIDE

17. Ultrasonography
 More reliable in revealing a joint effusion in early
cases.
 Widening of space between capsule and bone of
>2mm indicates effusion.
 Echo free  transient synovitis
 Positively echogenic  septic arthritis
 Ultrasound can detect joint-swelling.

18. Being a non- ionizing, easily available, non-invasive
and relatively cheap modality, Ultrasound should be
first line of investigation in a suspected case of
infective arthritis.

21. computed tomography:
 Early findings:
 Soft tissue swelling
 Joint space widening

22.  Late findings(2-3 w):
 Joint space narrowing
 Blurring of fat planes
 Increased density of fatty marrow
 Periosteal reaction
 Cortical erosion or destruction
 Intraosseous gas

23. CT Scan demonstrating soft tissue oedema localised to the
right sternoclavicular joint (A) and appearances of an
associated joint effusion, erosion and destruction of sternal end

24. CT of left hip joint The dd included septic
arthritis/osteomyelitis joint

25. Sagittal CT scan of C-spine shows a bone
erosion of the anterior portion of odontoid
process of C2 (arrow)

26. MRI findings:
• Synovial enhancement
• Perisynovial edema and joint effusion.
• Single or multiple radiolucent abscesses
• Assessment of the extent of tissue affected

27. Significance of CT and MRI:
• Cross-sectional imaging modalities such as CT and
MRI are now considered standard in the diagnosis of
septic arthritis because they have,
• Excellent spatial resolution
• Early detection
• Assessment of the extent of tissue affected
 Although expensive, they are sensitive and specific.

32. Nuclear medicine imaging:
 Nuclear medicine imaging can detect septic arthritis
10 to 14 days before changes are visible on plain
radiographs.
 Highly Sensitive but Nonspecific
 Inexpensive
 Focal hyper perfusion
 Focal hyperemia
 Focal bone uptake

33. Complications:
 bone destruction and dislocation of the joint
(especially hip)
 Cartilage destruction
 May lead to either fibrosis or bony ankylosis
 In adult partial destruction of the joint will result in
secondary osteoarthritis
 Growth disturbance
 Presenting as either localized deformity or shortening
of the bone

34. Thank you