Polyarthritis and fever may be manifestations of a wide variety of infectious and noninfectious diseases (Table 70.1). Prompt identification of treatable infectious diseases is important; even the diagnosis of nontreatable infections may have important consequences for the individual or for public health. In all cases, treatment is based on specifics that apply to the known or presumptive pathogen.

BACTERIAL INFECTIONS

Suppurative bacterial arthritis caused by Staphylococcus aureus, group A streptococci, and gram-negative bacteria usually is monoarticular, but 10% of patients have polyarticular involvement, occurring simultaneously or within 1 to 2 days. Risk factors for bacterial polyarthritis are listed in Table 70.2. Septic joints in such persons are not always red, hot, or exquisitely painful. The mortality rate is higher with polyarticular infection (>30%) than with monoarticular infection (≤10%) and has not changed in recent years. Therefore, just as for a monoarticular arthritis, prompt arthrocentesis of a polyarthritis is essential because delay in the diagnosis and treatment is the best predictor of an unfavorable outcome. Broad-spectrum antibiotic treatment should be started immediately.

The bacteria listed in Table 70.2 are more likely than others to produce polyarthritis. Neisserial arthritis, which is most often polyarticular, presents as migratory arthritis with chills, fever, and tenosynovitis in the wrist and ankle extensor tendon sheaths. Characteristic pustular or vesicular skin lesions often aid in diagnosis. Disseminated gonococcal infections occur more often in women, especially during menses and the second and third trimesters of pregnancy. Therapy should be started immediately after cultures are obtained.