Can a septic bursa be visualized on ultrasound?

Ultrasound Evaluation of Septic Bursitis

Yes, a septic bursa can be visualized on ultrasound, making it a valuable first-line imaging modality for diagnosing this condition. 1

Ultrasound Findings in Septic Bursitis

• Ultrasound can detect fluid collections within bursae, which is a key feature of septic bursitis 1, 2
• Septic bursitis typically appears as a distended bursa with either simple anechoic or complex hypoechoic fluid 2
• Characteristic features include:
  • Bursal distention that is typically unilocular and compressible 2
  • Thickened bursal walls with increased vascularity on Doppler imaging 1, 2
  • Internal debris or septations may be present in infected bursae 1, 2

Diagnostic Value of Ultrasound

• Ultrasound is recommended as the modality of first choice for detecting septic bursitis and other soft tissue infections 1
• It allows for real-time evaluation of bursal fluid collections and can distinguish them from other pathologies 1, 2
• Ultrasound has demonstrated high sensitivity for detecting abscesses and fluid collections, with one study reporting 96.7% sensitivity and 85.7% specificity 1
• The absence of fluid on ultrasound essentially excludes the diagnosis of septic bursitis 1

Advantages of Ultrasound for Septic Bursitis

• Readily available and can be performed as a bedside investigation 1
• Non-invasive and does not involve radiation exposure 1
• Allows examination of contralateral side for comparison 1
• Can assess vascularity and hyperemia using color Doppler without requiring IV contrast 1
• Facilitates ultrasound-guided aspiration for definitive diagnosis and treatment 1, 3

Limitations of Ultrasound

• Operator dependent, with variable sensitivity depending on the examiner's experience 1
• May have limited visualization of deeper structures compared to CT or MRI 1
• Cannot always differentiate between infectious and non-infectious causes of bursal fluid 2

Role in Management

• Ultrasound guidance significantly improves the success rate of diagnostic aspiration and therapeutic drainage 1, 3
• It allows for accurate needle placement while reducing the risk of complications 1, 3
• Serial ultrasound examinations can be useful for monitoring treatment response 4

When to Consider Alternative Imaging

• When ultrasound is not diagnostic, CT should be considered as the next imaging modality 1
• CT offers better sensitivity for detecting small foci of infection and is superior for visualizing soft tissue gas 1
• MRI provides excellent soft tissue contrast and is highly sensitive for detecting inflammation but is less commonly used as first-line imaging 1

Ultrasound plays a crucial role in both diagnosis and management of septic bursitis, offering a safe and effective means of visualizing the infected bursa and guiding therapeutic interventions 3, 5.