How are the many diseases causing polyarticular symptoms classified?
No single classification scheme can be used to differentiate the wide variety of diseases presenting with polyarticular symptoms. In most instances, the clinician uses several variables in combination to reduce the number of diagnostic possibilities. These variables include:
• Acuteness of onset of the process
• Degree of inflammation of the joints
• Temporal pattern of joint involvement
• Distribution of joint involvement
• Age and sex of the patient
• Extraarticular features