Presentation
Chronic shoulder pain. History of previous trauma since 2 years and shoulder arthroscope for "frozen shoulder" 6 months ago.
Patient Data
You can see:
- Marked gleno-humeral joint effusion with markedly thickened and enhancing synovium
- Erosions of the articular surfaces of the glenoid bone and humeral head with subchondral edema signal demonstrating low T1 and high T2 and GRE signal. The subchondral bone shows intense enhancement. The proximal humerus shows edema signal with post-contrast enhancement as well
- Erosion of the labrum glenoidale with muffed appearance
- Normal rotator cuff muscles and tendons
- No evidence of supraspinatus impingement
- Small subacromion / subdeltoid bursitis
- Enlarged axillary lymph nodes with intense enhancement
Case Discussion
The findings are compatible with chronic septic arthritis of the right shoulder joint as well as small subacromion / subdeltoid bursitis.
Synovial enhancement as well as perisynovial edema, and joint effusion are the clue findings for the diagnosis of septic arthritis in the proper clinical setting.
The differential diagnosis is rheumatoid arthritis (however, it could be an association and predisposing factor as well). Thickened edematous synovium with effusion in patient with chronic articular inflammation is the key diagnostic findings in the proper clinical situation. Erosions are common as well.