Diagnostic use of superb microvascular imaging in evaluating septic arthritis of the manubriosternal joint: A case report

BACKGROUND: Septic arthritis of the manubriosternal joint is a diagnostic challenge due to its rarity and anatomical characteristic. Conventional ultrasound, plain radiographs, and computed tomography are not able to confirm or even suspect arthritis early. Superb microvascular imaging is a new advanced Doppler technique in evaluating low-flow microvascular patterns. The higher sensitivity for increased peri-synovial vascularity helps to suspect septic arthritis and forms a methodical approach to using magnetic resonance imaging (MRI). CASE SUMMARY: A 34-year-old immunocompetent woman presented with a fever and a dull ache in the chest radiating to the right arm. Traumatic injury and the most common respiratory and cardiac disorders were ruled out. Blood cultures came back positive for Staphylococcus aureus, and sepsis was confirmed. A small lump was noted on the chest during the first week of hospitalization. Superb microvascular imaging was performed and septic arthritis of the manubriosternal joint was detected. MRI confirmed the diagnosis and showed septic arthritis of the manubriosternal joint with several localized abscesses behind the sternum. The patient was treated for three weeks with intravenous antibiotics and the outcome was favorable: Inflammatory markers became normal, and the lump disappeared. Three months later, the patient was examined for a new episode of mild pain in the sternum and was diagnosed with persistent perichondritis by ultrasound in comparison with MRI. CONCLUSION: Superb microvascular imaging is a useful tool for the early diagnosis of septic arthritis of the manubriosternal joint and following-up.