Cleavage of Arthritis Deformans into Two Types
In reviewing the researches of the foregoing writers it will be clearly seen that though they did yeoman service in differentiating broadly gout from the disorders grouped under Arthritis Deformans, there is little doubt that not for many years afterwards was their distinctiveness sufficiently realised. This may be in large part attributed to the fact that they still awaited the next great process of fission as applied to chronic joint disorders.
I allude in the first place to Charcot’s momentous discovery of the nerve arthropathies, and secondly, to the cleavage of arthritis deformans into the rheumatoid or atrophic, and the osteoarthritic or hypertrophic varieties.
It is to Vidal that we are indebted for the first clinical description of the atrophic type. Charcot in his lectures refers to it as the “Atrophic form of Vidal,” noting that in this variety “induration of the skin, a sort of scleroderma develops, the cutaneous covering is cold, pale, smooth, polished, and will not wrinkle, adding also that in such cases atrophy of the bones and muscles accompanies the wasting of the soft tissues.”
Notwithstanding this, Charcot, to our mind, unquestionably refers to the category of chronic articular gout certain of these examples of Vidal’s atrophic type of arthritis deformans. The reasons he adduces for their gouty nature are, to say the least of it, both conflicting and unconvincing. On the one hand, he admits that they are clinically indistinguishable from Vidal’s type, in respect of their pronounced atrophic changes; on the other, he postulates them as gouty even though the uratic deposits “either do not exist at all, or only mere traces of them, or when only the articular cartilages are invaded by the urate of soda.” It must be conceded that chronic articular gout and rheumatoid or atrophic arthritis are totally distinct affections.
Now as to the hypertrophic variety, or osteoarthritis, which, of the twain, more closely resembles gout, and whose confusion therewith is far from infrequent even at the present time. Sir Dyce Duckworth, while he recognises with Charcot a tophaceous form of chronic articular gout, postulates the existence of another type, arthritis deformans uratica. Unlike Charcot, however, he seems only to have included under this term instances of the osteoarthritic or hypertrophic variety. But like Charcot, his claim that this particular variety is of gouty nature seems to rest on equally frail foundations, as witness his statement that they “may be complicated with visible or invisible tophaceous deposits!”
That osteoarthritis and gout may coexist in the same individual is certain, and equally sure is it that uratic deposits may supervene in joints the seat of osteoarthritis. But it is now, I think, generally conceded that, despite these coincidences, gouty arthritis and osteoarthritis are wholly distinct disorders, of wholly different origin.
At this period of our historical résumé we see that by the withdrawal of these three great groups—rheumatism, the nerve arthropathies and arthritis deformans—the domain of gout has, through these several allotments, undergone substantial shrinkage.