Olecranon Bursitis: Ultrasound Differentiation of Septic and Aseptic Process

Clinical Context

Olecranon bursitis is visualized as a well-demarcated collection between the olecranon and skin, distended by fluid. According to sources, common causes of aseptic bursitis include chronic trauma, gout, and inflammatory arthropathy.

Ultrasound Findings of Aseptic Bursitis

Longitudinal oblique scanning demonstrates a bursa distended by fluid with low-level echoes, indicating high-protein or hemorrhagic contents. In chronic gouty bursitis, transverse projection reveals a bursa filled with soft tissue material containing multiple echogenic foci—calcified crystalline aggregates.

Ultrasound Findings of Septic Bursitis

According to Jacobson (2026), septic bursitis may present with hyperechoic foci of gas with 'dirty' acoustic shadowing (dirty shadowing) against a background of mixed hypoechoic and isoechoic bursal contents. The presence of gas is an important sign of infectious process.

Role of Doppler Ultrasound

Color Doppler imaging reveals moderate hyperemia of the thickened bursal wall and peribursal tissues; internal contents and septa typically do not demonstrate hyperemia. This assessment helps characterize the activity of the process; however, by itself does not differentiate septic from aseptic bursitis [to be verified].

Differential Diagnosis

According to Griffith (2025), when a fluid collection is found in the elbow region, one should consider: cystic accumulation from underlying structures (parameniscal, ganglion cyst—based on location), abscess/collection, as well as a cyst adjacent to the bursa (seroma, hematoma).

Verification

Differentiation of septic from aseptic process based on ultrasound signs alone is limited; when infection is suspected, aspiration of bursal contents under ultrasound guidance is performed for laboratory analysis [to be verified]. Treatment of aseptic forms includes rest, anti-inflammatory medications, injections of long-acting corticosteroids and local anesthetic under ultrasound guidance, and excision in resistant cases.

Practical Note

Small amounts of fluid are normal for certain bursae (subacromial-subdeltoid, deep infrapatellar, retrocalcaneal), which should be considered when interpreting findings.