248 Vide Charcot's and Ord's cases, loc. cit.
The partial form presents some peculiarities of causation—thus: it occurs chiefly in advanced life (senile arthritis), much less frequently in middle life, very exceptionally in the very young. Men are much more liable to it than women. It is chiefly this variety which follows injuries, blows, dislocations, pressure, etc., and the disease may then be limited to the injured joint and be monoarticular, or it may extend and become polyarticular, or rarely, as in Ord's case, even general. This monoarticular form appears to be sometimes induced by other local irritations of the articular structures than those following traumatic influences; and as foreign growths in joints and gouty irritation may respectively induce the lesions indicative of rheumatoid arthritis, so, it is probable, may simple chronic rheumatism; and this may be the true relationship existing between these several affections. It is doubtful at present whether purely local irritation or injury of a joint can originate the alterations belonging to rheumatoid arthritis—that is, in the absence of all predisposition to that disease or of the arthritic diathesis. Cold and dampness are generally admitted to be causes of the partial form, but the evidence on this point is not altogether satisfactory. It may be that chronic articular rheumatism is induced by the prolonged operation of damp cold, and that the prolonged rheumatic irritation, aggravated by constant use of the joint and by occasional violence, ultimately superinduces the profounder alterations characteristic of arthritis deformans. It appears highly probable that if the predisposition exist, any long-abiding irritation of a joint, whether the result of violence or disease, may ultimately originate the alterations of the cartilages and bones which obtain in rheumatoid arthritis.
As regards the etiology of Heberden's nodosities, and their relation to other affections of the joints, the following summary must suffice: They obtain chiefly in advanced life, but do occur rarely in the young; they are probably somewhat more frequent in women than in men; although more frequently seen in the upper classes, the poor are not exempt from them, no doubt because they are specially exposed to slight but oft-recurring injuries of their digits, such traumatism being an exciting cause of the disease, especially when confined to a single joint. The affection is sometimes hereditary; both it and the general or the partial forms of rheumatoid arthritis may coexist in the same family and even in the same person. The alterations in the joints are identical with those found in the general variety of rheumatoid arthritis, and exist without deposits of urate of soda (Charcot). It resembles the general form of the disease just mentioned in its tendency to involve many symmetrical articulations at the same time, and the partial form in the rarity with which it extends beyond the joints first attacked. While Heberden's nodosities, as Haygarth taught, do occur independently of gout and the gouty habit, I believe with Begbie249 and Duckworth250 that in some persons they are evidences of gout or the gouty diathesis.
249 Contributions to Practical Med., 1802, p. 29.
250 "On Unequivocal Gouty Diseases," St. Bartholomew's Hospital Reports, vol. xvi., 1880, p. 190.
Quite recently a woman aged forty-eight consulted me with these nodosities beginning upon the last joint of the fingers, while she was the subject of vesico-renal irritation and was passing free uric acid in the urine. Hutchinson has twice seen them in combination with a peculiar insidious and painless inflammation of the iris and vitreous body, which occurs in the children of the gouty, yet such children have no deposits of lithates in their joints, nor any lithiasis, nor acute paroxysms of true gout, and he considers that "the last joint arthritis is to be regarded as in part gouty, and in part a kind of articular chilblain."251
251 Trans. International Med. Cong., ii. p. 96.
Lastly, in some instances they are no doubt the hybrid offspring of an inherited tendency to both gout and rheumatoid arthritis.
No more important principle in pathology exists than has been of late years insisted upon, especially by Jonathan Hutchinson and in his recent lecture by Sir James Paget252—to wit, that "by inherited dispositions, accumulating and combining or converging in definite proportions, new diseases may be developed and old ones be variously modified."
252 Lancet, ii., 1882, 1017-1021.