The Joint Deformities of Chronic Gout
The palpable changes in the affected joints differ widely in different cases, and why is not apparent. Thus, the first attack, if of prolonged duration, may bequeath a legacy of crippledom comparable to that met with after repeated paroxysms. On the other hand, some, although they have suffered from the disorder off and on throughout their lives, yet escape those consecutive deformities which in others deform and cripple the hands and feet, though the disease may be of relatively brief duration.
But in the less fortunate cases the continued ravages of gout lead to a pitiful disablement of the affected limbs, reaching its acme in the hands and individual fingers, flail-like and semi-paralytic as they so frequently become.
Not only are the digits variously distorted, their joints more or less ankylosed, but the overlying skin, distended by the ever increasing subjacent uratic deposits, becomes thinned and purplish red in hue, and occasionally ulcerates. Similarly at ankle, knee, wrist and elbow thickening and deformity ensue as the concretions accumulate in and around the affected joints, these further accentuated by the correlated inflammatory and degenerative processes. Coincident deposits in the tendon sheaths and related bursæ contribute their quota, and at knee and elbow the bursal masses may reach extraordinary dimensions. Not only do the joints become deformed, but distorted also, through reflex muscular spasm and instinctive adoption of unnatural attitudes for the avoidance of pain.
So much for the broad outline of the picture presented, but a still closer scrutiny is called for. The deformities produced are the outcome of uratic deposits, which, as Charcot long since pointed out, take on the shape of “irregularly rounded or ovoid swellings, bunched, and either large at the base or just the opposite, i.e., provided with a pedicle.”
As shown in the coloured plate, the favourite site for their development is the dorsum of the hand or the vicinity of the metacarpo-phalangeal or mid-phalangeal joint. The resultant disfigurement of the hand is very characteristic. Irregular tuberous swellings surmount the knuckles, and spreading laterally, obliterate the fossæ between them and their fellows. The same extend forward over the first phalanges, from nigh the distal end of which again arise similar bossy excrescences over the mid-phalangeal joints. Encroaching thus upon the length of the first phalanx from either end, but little of its shaft is ultimately left exposed. In like fashion the mid-phalanx may be buried in uratic deposits, its contour wholly lost; and, the terminal phalanx participating, the digits become almost pedunculated, the nails projecting from the ends thereof—the “parsnip hand” of Sydenham. Such is the appearance presented in inveterate chronic gout.
Fortunately such examples are relatively rare, and a study of the condition in its earlier stages reveals some interesting features. The uratic deposits, it is important to note, are not located exactly at the level of the articulation. Unattached as they are to the articular ends, they are not compelled to, nor do they in any way, adapt themselves, as it were, to the contour or shape thereof. In short, the tophaceous formations are erratic, are not like osteo-arthritic nodules, erupted from and continuous with the articular bone ends. Again, relatively independent of the contiguous tissues, they, unlike osseous outgrowths, are slightly movable in lateral directions.
When of recent incidence, their consistence is soft, and, be they never so ancient, they do not attain the density and hardness of bony outgrowths. The overlying skin, to which they are sometimes adherent, takes on a peculiar glossy and satin-like texture, its dusky pink blotched with spots of dead white colour, i.e., subjacent uratic deposits.
In other particulars also they differ from bony outgrowths. The tophaceous masses may soften and disappear after exacerbations of arthritis, and others may form at different sites. Following such absorption or difference in their location, some increase in joint mobility may happily ensue. This same fortunate occurrence may follow discharge of the uratic masses through ulceration and perforation of the skin.