Polyarticular joint pain with fever poses a unique diagnostic challenge given the magnitude of complaint, urgency to identify the underlying cause, and the uncertainty of outcome. Knowledge of the most prevalent causes of polyarthritis associated with fever can facilitate an 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 (e.g., demographics, comorbidities, geography) help refine the diagnostic possibilities. The presence of fever is notable 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. This chapter will examine the diagnostic approach to polyarthritis and pyrexia.

History and physical exam

The diagnosis of any disease relies heavily on the history and physical examination. Eliciting an accurate history will identify those who are at risk for significant morbidity and mortality. The goals of the encounter are to: (1) relieve symptoms, (2) treat the underlying disease, and (3) avoid irreversible organ damage. Characteristics distinguishing arthritis include prolonged morning stiffness, warmth, erythema, tenderness to palpation, swelling, and joint effusion. Range of motion, muscle strength, and function may be limited around the inflamed joint. In an effort to reduce joint volume and pain, the patient may involuntarily hold the joint in a position of partial flexion. Hence, joint contracture may be evidence of an inflammatory process. The key elements that should be obtained from history and physical exam are as follows and simplified in Figure 71.1.