During a recent two-year period, five patients with chronic rheumatoid arthritis who had developed acute suppurative arthritis were encountered. Elderly patients with chronic debilitating arthritis and minor skin infections are most susceptible. Hemolytic Staphylococcus aureus is by far the most common microorganism involved. This often fatal complication may be easily overlooked as the clinical features simulate those of an acute, uncomplicated rheumatoid exacerbation.
David L. Rimoin, John E. Wennberg. Acute Septic Arthritis Complicating Chronic Rheumatoid Arthritis. JAMA. 1966;196(7):617–621. doi:10.1001/jama.1966.03100200057018