Polyarthritis

This chapter highlights polyarthritis. The co-occurrence of fever and arthritis educes a broad set of diagnostic considerations, especially infection. Yet, most forms of infectious arthritis typically involve one to three joints (monarthritis to oligoarthritis). The presence of a greater number of joints involved (polyarthritis) with fever evokes a more unusual and challenging range of diagnostic possibilities. Knowledge of prevalent forms of polyarthritis capable of fever can facilitate an early, accurate diagnosis and appropriate therapy. Polyarthritis is defined as inflammatory pain with swelling affecting four or more joints. The distribution, chronology of joint inflammation, and host factors help refine the diagnostic possibilities. The presence of fever is unique as most polyarticular conditions do not manifest substantial or sustained fever. Nevertheless, fever or pyrexia is further evidence of an inflammatory, infectious, or autoimmune disorder.