Septic arthritis in the adult caused by Streptococcus pneumoniae: a report of 4 cases and review of the literature.

OBJECTIVES: To identify coexistent diseases, clinical features, approaches to management, and predictors of outcome in patients with pneumococcal septic arthritis.
METHODS: Case series of 4 adults with Streptococcus pneumoniae septic arthritis seen at a university hospital, plus a review of 115 adults with pneumococcal septic arthritis reported in the medical literature from 1973 through 2003.
RESULTS: Among our 4 patients, 3 had polyarticular infections, joint prostheses were involved in 1, 3 had underlying joint diseases, and 1 had concurrent meningitis. Infection was caused by penicillin-intermediate/cephalosporine-susceptible S pneumoniae in 1 patient and penicillin-resistant/cephalosporine-intermediate S. pneumoniae in 1 patient. After a mean treatment duration of 6 weeks, all patients were clinically cured of infection. Review of the literature identified 115 cases of S pneumoniae septic arthritis in adults. Clinical data were available for 107 patients. Twenty-nine cases were polyarticular (26%), joint prostheses were involved in 15 patients (13%), and 61 patients had underlying joint disease (57%). Meningitis was a concurrent infection in 15 cases. The presumed primary focus of infection was the respiratory tree in 44 patients. Ninety-six percent of cases were caused by penicillin-susceptible organisms. Cure of infection with survival was achieved in 83% (79 of 95) of patients with native joint septic arthritis and in 67% (8 of 12) of patients with prosthetic joint infection. A good functional outcome (full range of motion or return to baseline range of motion) after infection was achieved by 44 of 71 patients (62%) with native joint infection and by 4 of 7 patients (57%) with infections of prosthetic joints. The likelihood of cure of infection or good functional outcome was not influenced by method of joint drainage.
CONCLUSIONS: S pneumoniae is an uncommon, but not rare, cause of septic arthritis in the adult. Many patients have underlying joint disease (especially rheumatoid arthritis) and coexistent alcoholism. Although most infections involve native joints, prosthetic joint infections comprise 13% of cases. Polyarticular disease occurs in approximately one quarter of patients. Most patients have a preceding or concurrent extra-articular focus of pneumococcal infection. To date, the majority of reported infections are caused by penicillin-susceptible organisms, so penicillin G or a third-generation cephalosporine such as ceftriaxone remains the appropriate treatment option. However, infection with drug-resistant organisms is likely to be an increasing problem in the future. With directed antimicrobial therapy and appropriate joint drainage, the outcome is generally good for patients with native joint infections. In contrast, only two thirds of patients with infections of prosthetic joints survive their infections. Approximately 40% of surviving patients experience functional impairment or chronic pain as a sequelae of their infection.