The morbid anatomy of simple chronic articular rheumatism will vary with the severity and duration of the disease. The alterations are such as chronic inflammation of a non-suppurative character might be expected to produce in the joints by one who had learned those characteristic of acute rheumarthritis. In the simple chronic form the proliferating process involves chiefly the synovial membrane, the capsular and other ligaments, and the periarticular tissues; to a less degree the cartilages, and to a much less degree, and exceptionally, the osseous surfaces. The synovial membrane is thickened, slightly injected, and its fringes hypertrophied and more vascular than normally. Little fluid usually exists in the joint unless during an exacerbation, when a moderate amount of thin, cloudy serum may be present; generally only a trace of thick, turbid fluid, containing oil-globules, and in severe cases débris of the cartilages, but no pus, is found. The fibrous capsule and ligaments become thickened, dense, and stiffened by hyperplasia; and sometimes the adjacent tendons and their sheaths, the fasciæ and aponeuroses, undergo similar alterations, so that the movements of the joints become seriously interfered with. In some cases this irritative hyperplasia specially involves these periarticular fibrous structures, and these, undergoing retraction, produce marked deviations, subluxations, and deformities of the articulations very like those observed in rheumatoid arthritis, although the osseous components of the joints are unaffected. Jaccoud gave to such cases the title of chronic fibrous rheumatism.211 It is worth noting that Jaccoud's, Charcot's,212 and Rinquet's213 cases of so-called "chronic fibrous rheumatism" developed out of acute articular rheumatism, while Besnier's was primarily chronic. In simple chronic rheumatism, if protracted, the cartilages also proliferate, lose their semi-transparency and polish, and become opaque and white; they are often rough and traversed by fissures, and occasionally present erosions; and these erosions are either naked or covered with a layer of newly-formed connective tissue, which may occasionally produce fibrous adhesions between the articular surfaces. Points of calcification occur in the cartilages and tendons in very chronic cases. Instances are observed in which the bones exhibit, to a slight degree, the alterations found in rheumatoid arthritis, and are probably transitional between the two affections. The muscles which move the affected articulations in severe cases are often atrophied, and the wasting imparts to the joints an appearance of considerable enlargement.
211 Vide Jaccoud, Clin. Méd. de la Charité, 23e Leçon, Paris, 1867.
212 Besnier, Dictionnaire Encyclopéd., etc., t. iv., p. 680 et seq.
213 Du Rheum. Artic. Chronique, etc., par Martial Rinquet, Thèse, Paris, 1879, pp. 28-33.
SYMPTOMS AND COURSE.—Simple chronic articular rheumatism presents many varieties. In the milder forms the patient experiences trifling or severe pain in one, or less frequently in two or more, joints, more especially in the knee or shoulder, or both, attended with want of power in the member or with stiffness in the affected articulation. The pain frequently is likewise felt in the soft parts, muscular and tendinous, near the joints, and is usually increased by active or passive movement; it is not always accompanied by tenderness, and rarely with local elevation of temperature or swelling. The wearying aching in the joint is of an abiding character, but is very liable to exacerbations, especially at night; and these come on just before atmospheric changes, such as a considerable fall of temperature, the approach of rain, variations in the direction of the wind, etc., and they usually continue as long as the weather remains cold and wet. A very common symptom is a creaking or a grating which may be felt and heard during the movements of the joint.
The above symptoms may rarely prove more or less constant by night and day for years, but far more frequently, at least at first, they last an indefinite period and disappear to recur again and again, especially in the cold and changeable seasons of the year. Although in the earlier attacks, and often for a long time, no alteration of structure is perceptible in the painful joints, yet in some instances slight effusion into the articulation may be observed during the exacerbations, or the capsule and ligaments may at length become slightly thickened, or the muscles may waste and produce an apparent enlargement of the joint; and this prominence of the articular surfaces may be increased by retraction of the tendons and aponeuroses—a condition which causes real deformities (deviations, subluxations, etc.) of the articulation and impairs more or less its movements. In very chronic cases a fibrous ankylosis may be established.
These last-mentioned conditions often entail great and long-continued suffering, and may even cause some anæmia and general debility; but very frequently the general health and vigor continue good, notwithstanding the permanent impairment of the functions of one or several of the large articulations, and the liability to exacerbations often amounting to attacks of subacute rheumarthritis from changes in the weather, fatigue, or exposure.
Besides the above varieties may be mentioned a not infrequent one consisting of a series of attacks of subacute articular rheumatism recurring at short intervals, involving the same joints, and attended with slight elevation of temperature, febrile urine, perspiration, and moderate local evidences of synovitis, heat, pain, tenderness, swelling, and effusion into the affected joints. This is an obstinate variety, and is often associated with rheumatic pain in the muscles and fibrous tissues of the affected member.
Simple chronic articular rheumatism, like the acute form, is most apt to affect the larger articulations, knees, shoulders, etc., but it frequently also involves the smaller ones of the hands and feet. Although usually polyarticular, it is prone to become fixed in a single joint, but even then it may attack several other articulations, and may migrate from one to another without damaging any.
The course of the disease is usually one of deterioration during persistent or recurring attacks, and in many cases the intervals of relief become shorter and less marked; the joints become weaker and stiffer; and although the pain may not increase and the general health may not be seriously impaired, yet the patients may continue for many years or the rest of their lives severe sufferers, unable to work, and often hardly able to walk even with the aid of a stick. Occasionally, after several years of pain and weakness, a sudden or slow improvement may set in and the patient become free from pain and lameness, and only experience some stiffness in the movements of the joints after several hours of rest, and slight thickening of the ligaments and capsule of one or more articulations. The duration of the disease is indefinite; the danger to life trifling.