Photo Rounds

Tender, swollen elbow

A 52-year-old woman with pemphigus vulgaris presented to her family physician (FP) with a painful, swollen left elbow. She was taking prednisone and mycophenolate mofetil for the pemphigus, which was under control. On examination, the patient’s elbow was red and tender; she was unable to fully extend it. She had no lesions on her skin or in her mouth.

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The FP suspected that the patient had septic olecranon bursitis and he was particularly concerned about the patient’s immunosuppressed status. Aspiration of the bursa demonstrated a yellow-green fluid with white cells and bacteria seen under light microscopy. The FP admitted the patient to the hospital for IV vancomycin and sent the fluid for culture. The laboratory reported gram-positive cocci on the Gram stain.

Olecranon bursitis can be aseptic—from repetitive trauma or systemic disease—or septic, most commonly from gram-positive bacteria.

Bursal fluid findings can help differentiate septic from aseptic olecranon bursitis.

  • The white blood cell (WBC) count is >30,000 in septic bursitis and <28,000 in aseptic bursitis. However, an elevated WBC count is also seen in rheumatoid arthritis or gout.
  • Neutrophils are seen in septic bursitis; monocytes are seen in aseptic bursitis.
  • Glucose is <50% of serum glucose in septic bursitis. It is >70% of serum glucose in aseptic bursitis.
  • Gram-positive organisms are found on the Gram stain in septic bursitis.

Aseptic olecranon bursitis is treated with an elbow pad, nonsteroidal anti-inflammatory drugs, and ice. Septic olecranon bursitis is treated with drainage and antibiotics. Septic bursitis should be treated until the fluid is sterile. Some experts recommend re-aspiration after 4 to 5 days of antibiotics and continuing antibiotics for 5 days after the fluid is sterile.

In this case, the patient was doing better 3 days after being admitted. The culture was reported as methicillin-resistant Staphylococcus aureus (MRSA). The organism was sensitive to doxycycline and the patient was sent home on oral doxycycline 100 mg twice daily to complete a 2-week course of antibiotics.

Photos and text for Photo Rounds Friday courtesy of Richard P. Usatine, MD. This case was adapted from: Chumley H. Olecranon bursitis. In: Usatine R, Smith M, Mayeaux EJ, et al, eds. Color Atlas of Family Medicine. 2nd ed. New York, NY: McGraw-Hill;2013:596-600.

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