A Rational Approach to an Understanding of the Arthritides *

The word "arthritis" means "inflammation of a joint" and "inflammation" is the reaction of a tissue to irritation. Note that the word "infection" does not enter into the definition as yet, although infection may be, and is the most frequent type of, the irritation which brings forth the inflammatory reaction. It is important to an accurate understanding of inflammation, however, that infection be thought of as one of the forms of irritation rather than as the sole cause of all inflammation. The unqualified use of the term "arthritis" applied to a patient's complaint of joint difficulty is of very little value in explaining the pathological changes in the joint and the causes which gave rise to those changes. There are many causes for joint inflammation and in order that we may understand the joint pathology from an etiological standpoint a classification of the various types of arthritis is necessary. The classification used here is not the accepted classification of joint inflammatory diseases, but it is an understandable classification and necessary to an understanding of this confusing group of diseases. In this classification, the arthritides are divided into "acute" and "chronic." An "acute" disease might be described as one which exists only for the average length of time necessary for the progressive changes of the inflammatory reaction to reach an end-point. A "chronic" disease is one which continues to be active beyond the average length of time necessary for the progressive inflammatory process to take place. This is not the place to discuss the many factors which determine acuteness or chronicity, but the most important factors in prolonging the process are embraced by the term "body resistance."