Septic bursitis

Background

  • Most common sites are prepatellar bursa and olecranon bursa

Clinical Features

  • Acute pain, tenderness, warmth, and erythema of affected bursa
    • None of which is seen in aseptic bursitis
  • Fever (<50%)

Differential Diagnosis

Evaluation[1]

  • Plain radiograph, CT, MRI usually not helpful
  • US may help guide procedures or help with diagnostic uncertainty
  • Bursal fluid aspiration
    • Both diagnostic and therapeutic
    • Do not perform if there is evidence overlying cellulitis
  • Procedure
    • Placed in flexed position, elbow and forearm rested on surface
    • Prep and drap
    • Plus/minus local anesthesia skin wheal
    • Approach with 18-22 ga needle from posterior aspect of bursa, aspirate until bursa is flat
    • Compressing bursa to help with aspiration
    • Arthocentesis should be performed if joint involvement suspected
  • Septic workup
    • Cell counts > 5000 - 20,000/µL depending on source
      • Predominance of PMNs
      • Cell counts < 2000/µL, with predominant mononuclear cells highly suggestive of nonseptic bursitis
    • Gram stain and culture
      • Gram stain with variable levels of sensitivities
      • Thus, high WBC count with negative gram stain should not exclude diagnosis
    • Elevated protein
    • Reduced glucose
    • Crystal analysis

Management

Antibiotics

Cover Staphylococcus aureus (80-90%) and Streptococcus

Outpatient Options

Inpatient Options

Disposition

  • Consider admission for:
    • Extensive purulent bursitis
    • Extensive surrounding cellulitis
    • Suspected joint involvement
    • Immunocompromised
    • Failure to respond to course of PO antibiotics

See Also

References

  1. Lohr KM et al. Bursitis workup. eMedicine. NOV 2017. https://emedicine.medscape.com/article/2145588-workup#c8