Current Concepts: Polyarthritis and Fever

Certain clinical and laboratory findings are useful in the differential diagnosis, but none are specific to a particular disease. [...]some diseases may present with more than one pattern (Table 2). Radionuclide scanning and magnetic resonance imaging may identify juxtaarticular osteomyelitis and effusions in deep locations such as the hip and sacroiliac joints11. Because delay in treatment is the best predictor of an unfavorable outcome,8,9 prompt arthrocentesis is essential. In this situation, the main challenge may be to identify another condition as the cause of fever and acute polyarthritis and to convince the patient that seropositivity is a reflection of previous illness. Since an enzyme-linked immunosorbent assay may be falsely positive in other inflammatory arthropathies, the more specific Western blot method should be used to confirm the presence of antibodies to B. burgdorferi. A direct pathogenetic role for HIV has been suggested but not yet documented. Since arthritis may be an early feature of AIDS, clinicians should be aware of the potential for HIV infection and obtain information about any predisposing factors in all patients with polyarthritis of new onset.