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

• Olecranon bursitis (nonseptic)
• Prepatellar bursitis (nonseptic)
• Cellulitis
• Septic arthritis

Evaluation

• 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 drape
  • 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
  • Arthrocentesis 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 a 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

• Clindamycin 300 mg PO three times daily x 14 days OR
• TMP/SMX 2 DS tabs PO two times daily x 14 days OR
• Dicloxacillin 500mg PO q6hr x10 days

Treatment followup with primary physician is important since the regimen may need extension to 3 weeks.

Inpatient Options

• Vancomycin 25-30 mg/kg IV loading then 15-20 mg/kg IV OR
• Clindamycin 600 mg (10/mg/kg) IV three times daily
• Linezolid 600 mg IV BID (10mg/kg Q8hrs for pediatrics)

Disposition

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

See Also

• Bursitis

External Links

• Septic Bursitis: ED Presentation, Evaluation, and Management on emDocs.net