Rheumatic disease: Diagnostic clues in the pattern of joint involvement

The diagnosis of rheumatic disease can often be made in the office or at the patient's bedside based on information from the history and physical examination. Useful dues can be garnered from the patient's age, family history of rheumatic disorders, and onset and course of the disease. However, the pattern of joint involvement - including the number of joints involved - and the presence or absence of extraarticular symptoms are the most helpful clinical details. A monarthritis suggests trauma; crystal diseases, such as gout; and infection. Acute monarthritis of the knee is a late manifestation of Lyme disease, which is now reported in more than 40 states; consider this diagnosis, even in patients who deny exposure to ticks or who cannot recall any skin lesions or rashes.