Bursitis

Bursitis is the inflammation of a bursa and is typically triggered by acute trauma, overuse, or an underlying inflammatory joint disease, such as rheumatoid arthritis or gout. Bursitis most commonly affects the olecranon, prepatellar, subacromial, or anserine bursae. Depending on which bursa is involved, the clinical presentation may include localized swelling, fluctuance, and/or pain with passive range of motion of the adjacent joint. Bursitis that is complicated by infection is referred to as septic bursitis and should be ruled out in patients with significant tenderness, erythema, and/or warmth of the inflamed bursa. Although bursitis is primarily a clinical diagnosis, imaging modalities such as x-ray, ultrasound, and/or MRI may be used to evaluate for alternative diagnoses or underlying joint disease. In patients with signs of acute inflammation, bursal aspiration with fluid analysis is indicated to rule out septic bursitis or gout. Conservative management (including rest, compression, and NSAIDs) is the mainstay of treatment for patients with nonseptic bursitis; intrabursal glucocorticoid injections may be used in refractory cases. Septic bursitis requires systemic antibiotic therapy and bursal drainage; surgical intervention is considered for patients with severe, recurrent, or refractory purulent effusions.

Pes anserine bursitis and trochanteric bursitis can occasionally contribute to pain syndromes that are primarily caused by tendinopathies; see “Pes anserinus pain syndrome” and “Greater trochanteric pain syndrome.”

• Nonseptic bursitis: inflammation of a bursa without infection
• Septic bursitis: inflammation of a bursa due to infection

• Nonseptic bursitis ^[1][2]
  • Local trauma (e.g., fall on the joint)
  • Overuse injury (e.g., due to excessive kneeling, leaning on the elbows)
  • Inflammatory joint disease (e.g., rheumatoid arthritis, gout)
• Septic bursitis: Typically preceded by minor injuries to the overlying skin ^[1][2][3]
  • Causative organisms: S. aureus (most common), Streptococcus spp.
  • Risk factors: immunocompromise (e.g., diabetes, chronic alcohol use), chronic skin or joint inflammation (e.g., atopic dermatitis, rheumatoid arthritis), prior nonseptic bursitis

• Olecranon bursitis: inflammation of the olecranon bursa typically caused by acute direct trauma or prolonged pressure ; ^[1]
  • Localized swelling and fluctuance over the extensor surface of the elbow
  • Significant tenderness, erythema, and warmth may indicate septic bursitis.
• Subacromial bursitis; : inflammation of the subacromial bursa often caused by repetitive overhead motion ^[1][4]
  • Shoulder pain exacerbated by reaching up
  • Anterolateral tenderness below the acromion
  • Positive shoulder impingement tests (e.g., pain with shoulder abduction beyond 60°)
• Prepatellar bursitis: inflammation of the prepatellar bursa typically caused by chronic pressure on flexed knees (sometimes referred to as “housemaid's knee”) or acute direct trauma ^[1][2]
  • Localized swelling and fluctuance over the kneecap
  • Significant tenderness, erythema, and warmth may indicate septic bursitis.
• Pes anserine bursitis: inflammation of the anserine bursa, often secondary to overuse in runners, or in middle-aged women in association with obesity and osteoarthritis
  • Medial knee pain that is worse when rising from a seated position or walking up stairs ^[2]
  • Localized tenderness and, sometimes, swelling over the anserine bursa
  • Can be associated with tendinopathy of pes anserinus and inflammation at its insertion site (See “Pes anserine pain syndrome.”)
• Trochanteric bursitis: inflammation of the trochanteric bursa (rare)
  • Lateral hip pain with localized tenderness over the greater trochanter
  • Can be associated with gluteus medius or minimus tendinopathy (See “Greater trochanteric pain syndrome.”)

General joint swelling and significant pain with passive range of motion of the elbow or knee should raise concern for arthritis rather than bursitis. ^[1]

Fever, signs of acute inflammation, and/or overlying cellulitis suggest septic bursitis. ^[1]

Bursitis is primarily a clinical diagnosis. ^[1][2]

• Bursal aspiration: Consider if signs of acute inflammation are present (to rule out septic bursitis or gout).
  • Fluid microbiology: Positive Gram stain and/or culture are diagnostic of septic bursitis.
  • Fluid cell count: WBC > 1000–5000 cells/μL can indicate infection (even if Gram stain is negative). ^[1][2][3]
• Imaging
  • Ultrasonography: can support clinical diagnosis and guide aspiration, if indicated
  • X-ray or MRI: can be used to exclude alternative diagnoses or evaluate for underlying conditions

Identification of monosodium urate crystals in bursal fluid indicates gout but does not rule out concurrent septic bursitis. ^[3]

Nonseptic bursitis ^[1][2]

• Rest, ice or heat, elevation, and NSAIDs
• Bursal aspiration for significant swelling
• Compression to prevent fluid reaccumulation
• Consider intrabursal glucocorticoid injection with specialist guidance. ^[1]

Septic bursitis ^[1][3]

• Antibiotics: Empiric coverage for S. aureus and Streptococcus spp. ^[1][3][5]
  • Immunocompetent with mild to moderate infection: Consider trial of outpatient oral antibiotic therapy for 10–14 days
    • No MRSA risk factors: dicloxacillin OR a 1^st generation cephalosporin, e.g. cephalexin ^[1][5]
    • MRSA risk factors or penicillin allergy: sulfamethoxazole/trimethoprim OR clindamycin ^[1][5]
  • Immunocompromised, poor follow-up, or severe infection : Inpatient treatment with IV vancomycin ^[1][5]
  • Adjust antibiotic therapy according to culture results.
• Bursal aspiration: : Repeat every 1–3 days as needed for persistent purulent effusion. ^[1][5]
• Surgical intervention: Consider for severe, recurrent, or refractory purulent effusions. ^[1][5]
  • Incision and drainage
  • Bursectomy

Oral antibiotic therapy for septic bursitis may fail in up to 50% of patients. Maintain a low threshold for admission and inpatient IV antibiotic therapy. ^[1][5]