The term septic arthritis usually refers to bacterial infection in a joint but also includes fungal and mycobacterial infections. Septic arthritis due to bacterial pathogens is often a dangerous and destructive form of acute arthritis. Predisposing factors, pathophysiology, clinical manifestations, diagnosis, and treatment of nongonococcal bacterial arthritis are reviewed here. Prosthetic joint infections, gonococcal arthritis, and fungal and mycobacterial arthritis are discussed separately because of their unique clinical manifestations. (See "Clinical manifestations and diagnosis of prosthetic joint infections" and "Treatment of prosthetic joint infections" and "Disseminated gonococcal infection" and "Skeletal tuberculosis".)
The prevalence of bacterial arthritis among adults presenting with one or a few acutely painful joints has been estimated to range from 8 to 27 percent, the lower figure arises from a consecutive series of 100 patients presenting to an urban hospital emergency department; the latter figure is based on a study of 75 patients presenting emergently in Taiwan [1,2]. These series included some patients with prosthetic joints and a small minority in whom the final diagnosis was gonococcal septic arthritis.
Predisposing factors for septic arthritis in adults were identified in a 2007 systematic review that included a total of 6242 patients with acutely painful joints ; 653 (10 percent) had septic arthritis. The predisposing factors and their predictive value (reflected by the estimated positive likelihood ratios [+LR]) are summarized as follows [3,4]:
●Age greater than 80 years