A 42-year-old man with a history of metastatic lung cancer on chemotherapy and daily steroid therapy presented to the ED with right elbow pain. The pain had begun the day before, and the patient denied history of trauma, overuse, or increased time or pressure on his elbows. His review of systems was otherwise unrevealing.
Physical exam was notable for a right elbow with focal swelling posteriorly with associated tenderness to palpation and pain with range of motion. No overlying skin changes or pain with axial loading were noted. The remainder of his exam, including other joints, was unremarkable. Vital signs were within normal limits, and the patient was afebrile.
Initial evaluation in the emergency department was notable for an elevated lactate (3.1 mg/dL), elevated C-reactive protein (26.5 mg/L), and a white blood cell count of 11.3 x109/L. An x-ray of the right elbow is shown below. What diagnosis is of most concern, and what are next steps to evaluate and treat?
Find the diagnosis and case discussion on next page.
Diagnosis: Septic Olecranon Bursitis
The x-ray demonstrated a small joint effusion and soft tissue swelling of the elbow. An aspirate of the olecranon bursa demonstrated brown, turbid fluid with a nucleated cell count of higher than 260×109 per liter and nearly 50×109 red blood cells per liter, with a gram stain notable for gram-positive cocci in clusters. The patient was started on vancomycin and admitted to the hospital for septic olecranon bursitis.
The olecranon bursa is a superficial fluid-filled sac that sits posterior to the olecranon process. Inflammation of these superficial bursas can be infective (septic) or sterile (aseptic). Approximately two-thirds of these superficial bursitis cases are thought to be aseptic secondary to acute injury or overuse, crystal deposition, or systemic inflammatory disease. (Arch Intern Med 1979;139:1269.)
Septic bursitis, on the other hand, is usually caused by direct trauma to the overlying skin with transcutaneous spread of infectious microorganisms. Staphylococcus aureus is by far the most common causative agent in septic bursitis, although streptococcal species are also frequently associated with septic bursitis. Numerous other species including gram-negative bacilli and mycobacterium have been isolated in immunocompromised patients, and polymicrobial infections account for approximately 10 percent of cases. (J Shoulder Elbow Surg 2016;25:158.)
Clinically distinguishing aseptic from septic bursitis can be difficult. The presence of a fever is thought to be relatively specific for septic bursitis but not particularly sensitive, with approximately 40 percent of patients with confirmed septic bursitis presenting with a fever. Overlying signs of cellulitis are more commonly seen in septic bursitis than nonseptic bursitis (60% vs 25%, respectively). Inflammatory markers can be elevated in septic and aseptic cases. Fluid aspirates from septic bursitis tend to have higher white blood cell counts exceeding 30,000/mm3 with a neutrophilic predominance (aseptic bursitis white cell counts < 28k/mm3). The glucose-to-serum ratio can also help characterize septic bursitis, and is less than 50 percent in 90 percent of cases. (J Emerg Med 2009;37:269.)
Given the difficulty of clinical diagnosis, all cases of suspected olecranon bursitis should be drained. If the aspirate suggests septic bursitis, initial antibiotic therapy should be guided by the severity of presentation and individual patient risk factors. Uncomplicated septic bursitis in an immunocompetent patient can be managed with dicloxacillin or clindamycin. Doxycycline or trimethoprim-sulfamethoxazole can be considered in patients with risk factors for MRSA. Admission and broad-spectrum coverage to include IV vancomycin may be prudent if the clinical presentation is severe or if the patient is immunocompromised. Duration of therapy will depend on clinical response, but many cases require two to three weeks of antibiotics. Antibiotic guidelines remain based on consensus because large-scale studies are lacking.
Surgery or repeated drainage may be considered if the patient does not respond to conservative management. Surgical management as a first-line therapy is less likely to be successful and more likely to be associated with complications such as the creation of a chronic sinus tract when compared with aspiration. Corticosteroid injections are not indicated in septic or aseptic bursitis. Some evidence suggests that corticosteroids may shorten recovery times, but they are associated with more than double the rates of complications. (Arch Ortho Trauma Surg 2014;134:1517.)
The patient was hospitalized overnight for continued administration of IV vancomycin. The patient was noted the following day to have rapid clinical improvement, and was discharged home with a two-week course of trimethoprim/sulfamethoxazole. Unfortunately, his swelling and pain worsened shortly after returning home, and he presented to another hospital for further evaluation. The patient had a surgical washout of his right olecranon bursa, a wound vac was placed, and he was started again on IV antibiotics before transitioning to oral cephalexin. The patient ultimately recovered without further complications.
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