Thus, recently a friend of mine came across an instance of what he deemed acute gout in a metacarpo-phalangeal joint. Its failure to respond to colchicum and the growing intensity and extent of the local inflammation suggested incision, when, lo, pus issued, to the subject’s comfort, but to his own chastening!
There are, however, many more likely sources of fallacy, these, too, of the most diverse type, inasmuch as they differ according to the exact location in the foot of the assumed gouty process. For while the big toe is the site of predilection for the initial manifestation, it is not always so. The primary outbreak may be located in any of the smaller joints of the foot, or outside them in related structures: in the heel, the sole, or the tendo Achillis. These vagaries greatly enhance the difficulties of diagnosis. For the process of differentiation will vary according to the particular joint or structure involved, the predilections of certain infective processes, not to mention the marked liability of the foot to painful disturbances of static origin.
Differential Diagnosis
Inasmuch as the primary outbreak may be located in any part of the foot, we purpose, for reasons just cited, dealing seriatim with gout in (1) the big toe; (2) the instep; (3) the heel; (4) the sole.
Gout in the Big Toe
Infections.—There is no â priori reason why any of the infections may not find a nidus in the first metatarso-phalangeal joint. Thus, Garrod, as we know, held gouty subjects specially liable to pyæmia. In rare instances, the primary focus has been in or near the great toe, and has consequently been mistaken for gout. The rapid progress of the disease would of course soon clear up the nature of the case. But if the subject has previously suffered from gout, such a diagnostic error at first sight is quite excusable. Accordingly, as a safeguard in all doubtful cases, inquiry should be made as to the existence of bladder troubles, piles, etc., especially any recent operation in this or other regions.
Again, while gout in its articular form is rarely, if ever, met with in children, it must be recalled, on the authority of Sir James Goodhart, that rheumatism in their instance is occasionally limited to one joint. Moreover, this distinguished physician actually saw it localised in the great toe, “in a case in which the subsequent course of the disease showed that it was acute rheumatism.”
Acute Gonococcal Arthritis.—We may recall that Van Swieten, a disciple of Boerhaave, held that sometimes a wife while nursing her gouty husband had contracted the same disorder. A tribute, we fear, to Van Swieten’s diplomacy rather than to his clinical acumen—an euphemism for gonorrhœal rheumatism!
Of course in adolescents or in young adults monarticular pain, with or without swelling, heat, or redness, should not suggest “gout,” but an infective disorder either in the joint or the related bone-ends. At the same time middle-aged men enjoy no immunity from gonorrhœa, and we may add that gonococcal infection of the metatarso-phalangeal joints is not so uncommon. When located in that of the great toe, it is easy to see how readily the acute arthritis may be confused with gout. But, unlike the latter, its duration is measured by months or weeks rather than by days. It is well to recollect, too, that “gouty” persons are more prone to develop arthritis following gonococcal infection. Given therefore a history even remote, we should in doubtful cases recall the longevity of the organism, its persistence in the prostatic recesses, and the need for bacteriological investigation.
Traumatic Lesions.—Its exposed situation renders the big toe very liable to trauma. Often, too, the injury being slight, and not followed by any immediate consequences, the connection may easily be overlooked. A blow or a fall may readily bruise the synovial membrane without at first any external sign. But given trivial hæmorrhage into the cavity or subjacent tissues, an acute synovitis with effusion is induced.