Musculoskeletal · Overuse Injuries
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Overuse or direct trauma inflames a bursa or tendon; classic examples are olecranon bursitis (student's elbow) and prepatellar bursitis (carpet layer's knee).
Key exam finding is pain with active and resisted motion but preserved passive range, distinguishing it from true arthritis (painful active AND passive motion).
When septic bursitis is suspected (especially olecranon), aspirate the bursal fluid; septic fluid is purulent with leukocytes typically >30,000 (mean ~75,000) cells/mm3 and positive culture.
Send aspirate for cell count, Gram stain, culture, and crystal analysis to separate septic from crystal or aseptic causes.
Septic bursitis requires antibiotics covering Staphylococcus (including MRSA) and Streptococcus, with drainage as needed, and generally responds well to oral antibiotics.
Aseptic bursitis/tendonitis is treated with rest, ice, compression, NSAIDs, and activity modification.
Avoid corticosteroid injection if infection is possible, and avoid it in the patellar/Achilles tendons given rupture risk.
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A 38-year-old plumber presents with 2 days of a swollen, red, warm, and tender posterior elbow with a small overlying skin abrasion. He has a low-grade fever. Passive flexion and extension of the elbow are relatively preserved, but there is fluctuant swelling directly over the olecranon. Aspiration yields purulent fluid with a leukocyte count of 80,000 cells/mm3.
Which of the following is the most appropriate next step in management?
Start antibiotics covering Staphylococcus (including MRSA) and Streptococcus.
Purulent olecranon bursal fluid with a markedly elevated leukocyte count and an overlying skin breach indicates septic bursitis, most commonly from Staphylococcus aureus. Empiric coverage for Staph (including MRSA) and Strep is indicated; corticosteroid injection is contraindicated when infection is present.
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Etiology / Epidemiology
Inflammation of a bursa or tendon from overuse/repetitive trauma; classic examples olecranon bursitis (student's elbow) and prepatellar bursitis (carpet layer's knee).
Clinical Manifestations
Localized pain, swelling, and tenderness over the bursa/tendon; pain with active and resisted motion but preserved passive arc.
Diagnosis
Clinical; aspirate the bursa when septic bursitis is suspected (especially olecranon) to exclude infection or crystals.
Treatment
Rest, ice, NSAIDs; antibiotics covering Staph (incl. MRSA) and Strep for septic bursitis; avoid steroid injection if infection possible.
Prognosis
Most aseptic cases resolve with conservative care; septic bursitis usually responds well to oral antibiotics.
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Epidemiology & Etiology
Bursitis is an inflammatory process involving any of the more than 150 bursae in the body and may be caused by repetitive trauma/overuse, direct trauma, infection, crystal deposition (gout/pseudogout), or rheumatologic disease. Tendonitis is analogous inflammation of a tendon. Classic occupational examples include olecranon bursitis (student's elbow) and prepatellar bursitis (carpet layer's knee). Common tendonitis sites include the rotator cuff/subacromial space, patellar tendon (jumper's knee), and the Achilles.
Pertinent Anatomy
A bursa is a fluid-filled synovial sac that reduces friction between tendons, bone, and skin (e.g., olecranon, prepatellar, subacromial, trochanteric). Tendons attach muscle to bone and pass through sheaths near joints. Superficial bursae (olecranon, prepatellar) are especially prone to direct trauma and to inoculation, predisposing to septic bursitis.
Pathophysiology
Repetitive friction or a single direct blow incites synovial inflammation, effusion, and pain. In tendonitis, microtears and degeneration of collagen produce inflammation at the tendon or its insertion. Septic bursitis arises from direct inoculation through overlying skin breaks, most often by Staphylococcus aureus (including MRSA) and Streptococcus species; crystal-induced bursitis results from urate or calcium pyrophosphate deposition.
Clinical Manifestations
Patients present with localized pain, tenderness, warmth, and swelling over the involved bursa or tendon. There is pain with active and resisted movement, whereas a true arthritis hurts with both active and passive motion. Septic bursitis shows erythema, warmth, fluctuance, and sometimes fever, frequently with an overlying skin breach. Rotator cuff/subacromial tendonitis produces a painful arc of abduction.
Diagnosis
Diagnosis is clinical based on focal periarticular tenderness with preserved passive joint motion. When septic bursitis is suspected (especially olecranon), aspirate the bursal fluid: septic fluid is purulent with markedly elevated leukocytes (typically >30,000, mean ~75,000 cells/mm3) and a positive culture, distinguishing it from aseptic, crystal, or inflammatory causes. Send fluid for cell count, Gram stain, culture, and crystal analysis.
Treatment
Aseptic bursitis/tendonitis is treated with rest, ice, compression, NSAIDs, and activity modification. Septic bursitis requires antibiotics covering Staphylococcus (including MRSA) and Streptococcus, with drainage as needed; it generally responds well to oral antibiotics. Corticosteroid injection can help refractory aseptic tendonitis but must be avoided if infection is possible and avoided for patellar/Achilles tendons given rupture risk.
Prognosis
Most aseptic cases resolve over weeks with conservative measures, though recurrence with continued provoking activity is common. Septic bursitis usually responds well to drainage and oral antibiotics with full recovery when treated promptly.
Differential Diagnosis
Septic arthritis: pain with active AND passive joint motion, intra-articular effusion, systemic toxicity.
Gout/pseudogout: acute crystal arthritis; aspirate shows negatively (urate) or positively (CPPD) birefringent crystals.
Cellulitis: diffuse skin erythema/warmth without a discrete bursal effusion.
Tendon rupture: sudden loss of function and a palpable defect (e.g., positive Thompson test for Achilles).
Fracture: focal bony tenderness with positive imaging after acute trauma.