Diagnostic Approach for Elbow Bursitis
Begin with clinical assessment focusing on signs of infection (tenderness, erythema, warmth, fever, skin lesions), followed by bursal aspiration with synovial fluid analysis when septic bursitis is suspected, as distinguishing septic from aseptic bursitis is critical for appropriate management. 1
Initial Clinical Evaluation
Key physical examination findings to assess:
- Tenderness is present in 88% of septic cases versus 36% of aseptic cases 1
- Erythema or cellulitis occurs in 83% of septic cases versus 27% of aseptic cases 1
- Warmth is found in 84% of septic cases versus 56% of aseptic cases 1
- History of trauma or visible skin lesion is present in 50% of septic cases versus 25% of aseptic cases 1
- Fever occurs in 38% of septic cases but is absent in aseptic cases 1
Important caveat: Physical examination and laboratory findings overlap significantly between septic and aseptic bursitis, making clinical distinction difficult without aspiration 1. The presence of fever is the most specific finding for septic bursitis, though it is only present in approximately one-third of cases 1.
Imaging Approach
Plain radiographs (AP and lateral views) should be obtained initially to rule out osseous pathology, heterotopic ossification, soft tissue calcification, occult fractures, or underlying joint disease 2, 3. Radiographs complement subsequent advanced imaging if needed 4.
Ultrasound is highly effective for visualizing superficial bursae and can demonstrate bursal fluid, wall thickening, and internal debris characteristic of bursitis 5. High-resolution ultrasonography has particular advantages for easily accessible superficial structures like the olecranon bursa 5.
MRI without contrast is indicated when:
- Radiographs are normal but symptoms persist 2, 3
- Underlying soft tissue pathology or nerve entrapment is suspected 2, 3
- Differentiation from other elbow pathology (tendinopathy, osteochondral lesions) is needed 4, 2
Patient positioning for ultrasound examination:
- Sitting position with elbow flexed at 90° angle 4
- Hand placed on hip or thigh with moderate internal rotation of humerus for dorsal scans 4
Bursal Aspiration and Fluid Analysis
Aspiration is essential when septic bursitis is suspected based on clinical findings, particularly when erythema, warmth, or fever are present 6, 1.
Synovial fluid analysis should include:
- White blood cell count: Elevated WBC (>3000 cells/mm³) suggests infection 6
- Gram stain: Immediate identification of bacteria 6
- Culture and sensitivity: Staphylococcus aureus is the most common pathogen 6, 1
- Crystal analysis: To exclude gout or pseudogout as alternative diagnoses 7, 5
Critical pitfall: A case report demonstrated that initial treatment with oral antibiotics alone for confirmed septic bursitis (S. aureus, WBC 3040 cells/mm³) resulted in interval worsening requiring hospitalization and surgical washout 6. This highlights the importance of close follow-up and low threshold for escalating treatment.
Diagnostic Algorithm
Assess clinical presentation for signs of infection (tenderness, erythema, warmth, fever, skin lesions) 1
Obtain plain radiographs (AP and lateral views) to exclude osseous pathology 2, 3
Perform bursal aspiration if any signs suggest septic bursitis 6, 1
Analyze synovial fluid for cell count, Gram stain, culture, and crystals 6, 7
Consider ultrasound for visualization of bursal characteristics and to guide aspiration if needed 5
Order MRI without contrast if diagnosis remains unclear or underlying soft tissue pathology is suspected 2, 3
Special Considerations
Immunocompromised patients require heightened suspicion for atypical organisms, as demonstrated by a case of Exophiala oligosperma causing chronic olecranon bursitis in a patient on immunosuppressive therapy for Wegener's granulomatosis 8. This patient required aspiration and intrabursal amphotericin B for successful treatment 8.
Chronic bursitis may require advanced imaging to exclude underlying conditions such as inflammatory arthropathies (rheumatoid arthritis, psoriatic arthritis, gout), degenerative diseases, synovial tumors, or pigmented villonodular synovitis 5.
Comparison with the contralateral elbow is often useful when interpreting imaging findings 2, 3.