ARTHRITIS DEFORMANS (rheuma toid arthritis, or osteo-arthritis), a group of chronic progressive diseases of thejoints chiefly affecting the articular cartilages, bones and synovial membranes, and producing loss of function and great deformity from ossifi cation of some parts of the joint and atrophy of others. Their origins are various, some of which are known and some still under investi gation, the external appearance of the deform ity showing less variation than the internal causes. Thus there are chronic arthropathies which produce the characteristic deformities and result from chronic gonorrhoea of the joints; others follow tonsillar infections, others are related in some way to infections from the teeth. In the majority of the cases there are unconscious mental factors — chiefly, hate re actions — which in some, as yet not perfectly clear manner, have a very definite influence upon the nervous regulation of the bony and joint metabolism, permitting toxic, bacterial, dietetic or climatic factors to have their in fluence. Though sometimes spoken of as rheu matic gout, they are believed to have little in common with rheumatism or gout, but may coexist with either. This type of disorder is very rare in children, occurs occasionally in old age, is more common between 25 and 50, and in females than in males. In certain of its forms, it most often appears after the meno pause, though it may occur earlier, as when following parturition. Heredity plays a part in certain arthropathies which come tinder this group. In the older descriptions one reads of two theories as to the immediate cause of the affection. For previously the group of different diseases were treated as one disease.
The first, the nervous or neuropathic theory, is based upon the symmetrical distribution of the joint-lesions, the trophic changes in the skin, nails, etc., etc., the frequent pre-existing mental disturbances, shock, grief, worry and the like, the disproportionate muscular atrophy, and the similarity of the lesions to those ar thropathies of locomotor ataxia and other affections of the spinal cord. The second or infectious theory is derived from the facts that micro-organisms have been found in the fluids and tissues of the joints, that the dis ease sometimes begins with an acute onset, as do many of the infectious diseases, and that enlargement of the spleen and lymph glands is found in some cases. It is difficult to say which tissue is primarily at fault but sooner or later nearly all are involved. The
synovial membrane inflames and papillary outgrowths and cartilaginous nodules form upon it. These last may undergo fatty degen eration or they may ossify. They may slip into the joint-cavity. If serous effusion occurs it is absorbed early in the disease. The car tilages lose their cells, become fibrillated and soft and are removed by friction and absorp tion. The ends of the bones (the interarticu lar cartilages being absorbed) by friction be come smooth, rounded and shiny like polished ivory (eburnated). The eburnated surfaces, by attrition, become grooved and minute per forations of the Haversian canals result. De posits of new bone form around the margins of the joints and may be often felt externally. The muscles atrophy and are of a brownish color. Fibrous adhesions and bony anchylosis occur. Some of the small joints of the fin gers for example may move a little, but the knees, etc., may be interlocked by reason of the rims of bony material deposited. Dis location or subluxation may result. The periosteum along the shafts of the bones may thicken or ossify in nodules. A combined hypothesis which deals with both sets of fac tors with interplay between is probably nearer the real facts. In certain cases the nervous instability is accompanied by endocrinous — thyroid—deficiency. An acute form of a general or multiple progressive type is rare after 40. Smaller joints become simultaneously painful, tender and swollen but not red as in rheumatism; there is no migration from joint to joint, the affected joints are inflamed, while others are becoming diseased. Pa tients are anwmic, mentally depressed and complain of headache and malaise. Fever seldom goes above F. Temporary im provement occurs, hut the disease advances. The chronic form of this type is insidious and more common. One joint (of finger or toe) is involved; the disease affects the correspond ing joint and then other joints; pain may be mild or very severe; there are delusive inter vals while the disease marches on. After months, or it may be years, all or nearly ar of the joints are thickened, rigid and distorted The hands are bent toward the ulnar cio fingers strongly flexed, nails in the palms the hands. The thumbs, though drawn may be used. The knees are generally cro The general health through it all may be as visceral lesions are uncommon.