Clinical Associations of Gout and Granular Kidney

It cannot be denied that gout and granular kidney are frequently met with in close association. But neither can it be disputed that in these disorders, as in many others, their outward affinities do but hark back to inward disparities. The occasional overlapping of the two affections, the trenching of the one upon the clinical or pathological territory of the other, must not blind us to the essential distinctness of the two morbid entities. Doubtless to the earlier advocates of the renal theory their not infrequent co-existence bespoke some hidden nexus, and at least seemed confirmatory of their views as to the pathogeny of gout. But, even if we allow that the connexion between the two disorders seems superficially intimate, it cannot be gainsaid that it is neither constant nor essential. For we have to recollect that—

(1) Some gouty subjects never develop granular kidney.

(2) Some individuals with granular kidney never develop gout.

Also we have to recall that—

(1) Paroxysms of gout often occur for many years before the symptoms of interstitial nephritis develop.

(2) In persons of gouty stock acute attacks may ensue at an age at which nephritis is practically unknown.

Apart from the difficulty of reconciling these disparities, we cannot overlook the fact that both gout and granular kidney are very common diseases, sufficiently common, as Samuel West pointed out, to be not infrequently associated accidentally, without any cause or connection. Again, both affections, be it observed, are prone to develop in the middle and later decades of life. In light of this, is it not readily conceivable that both may arise independently, mere coincidences, both evidences of pre-senilism? Hastings Gilford, indeed, classes gout with syphilis, lead, and alcohol as amongst “the chief promoters of pre-senility.”

Again, certain toxic agents which predispose to or initiate renal mischief also favour apparently the incidence of gout, e.g., lead and alcohol. Samuel West, discussing the relationship of both gout and lead to granular kidney, maintains that, though each may produce chronic change in the kidney, neither of them causes granular kidney. But the presence of granular kidney, he holds, greatly enhances the liability of the victim to gout on the one hand and plumbism on the other; also, to both together and in each affection alike markedly increases the gravity and the risk.

Sir William Roberts, too, has some wholly relevant observations on this point. Thus all will agree with him that “it is difficult to conceive that plumbism induces the same constitutional diathesis as that which obtains in true gout.” He held that gout and plumbism, though they differ in all other respects, yet have one point in common, a tendency to uratic deposition. But such precipitation, he contended, was the outcome of a gouty tendency, reinforced by lead poisoning; or if, on the other hand, uratic deposits occurred in plumbism, the same had but accentuated a pre-existing gouty diathesis. In this connexion, too, it should be recalled that the frequent association of gout and lead poisoning which exists in London is not seen in the North of England or in North America.

Is it not clear, then, that reflection on the broad clinical affinities exhibited by gout and granular kidney does but emphasise the essential distinctness of the two morbid entities? Inferentially, too, it lends no colour to the assumption that gout is of primary renal origin.

That the victim of gout, despite uricæmia and those unequivocal tokens, tophi, may, notwithstanding repeated arthritic outbreaks, be in the intervals in sound if not exuberant health, is a clinical truism. His kidneys, too, may, as far as can be ascertained, be normal; and his blood pressure not beyond what might be expected at his age. His output of uric acid may but touch the lower normal limit or a little less, and his metabolism of purin-rich foods be but a little protracted. Thus he runs his course, more frequently than not a strenuous one, chequered by occasional outbreaks which not seldom he regards as salutary rather than otherwise. Then, sooner or later, in one, two, or even three decades, that Nemesis of age, arterio-sclerosis overtakes him with its correlated chronic nephritic change.

Is not this very reminiscent of what Walker Hall reminds us of, the sequence of events in lead poisoning and alcoholism? “These poisons affect the general metabolism adversely and are connected with disturbances of purin assimilation and output. At a later stage they produce arterio-sclerosis and renal insufficiency.” And as he shrewdly observes, “It is, therefore, of importance to exactly appraise the stage of the disease when interpreting the results of experiments upon gouty individuals. When this obtains widened application, many generally accepted statements will have to be re-written.”

In conclusion, therefore, we see that the weight of clinical evidence is against the primary renal origin of gout, for not only are renal changes frequently slight, but they are often entirely lacking in gout. Confronted with these difficulties, the question inevitably rises as to whether there does not exist a special morbid entity, gout, which develops independently of renal abnormalities?

CHAPTER XI
URICÆMIA IN GOUT

In the summer of 1848, Garrod made his momentous announcement that “the blood in gout always contains uric acid in the form of urate of soda, which salt can be obtained from it in crystalline state.” Some eleven years later in his classic work on gout, he reiterated his affirmation, but appended thereto the words, “in abnormal quantities.” Garrod’s analyses were mainly qualitative, but, at any rate, in one instance, he obtained from a gouty patient the equivalent of 5 mg. of uric acid per 100 gm. of blood serum, maintaining, however, that this amount was much below that really present.

But not until 1895 was a series of quantitative estimates undertaken when Klemperer in three gouty subjects passing through an attack found the blood content of uric acid to be 6·6 mg., 8·8 mg., and 9·5 mg. per 100 c.c. of blood. Some years later, Magnus Levy, investigating seventeen gouty individuals, found that the amount of uric acid in the blood ranged from 2·1-9·5 mg. per 100 c.c.

Brugsch and Schittenhelm noted that, in gouty victims, uric acid was still present in the blood even when they had been on purin-free diet for weeks or months. They held endogenous uricæmia to be a constant symptom in gout. Even as late as 1913 the former investigator contended that, in a healthy person on a purin-free diet, the presence of uric acid in the blood cannot be satisfactorily demonstrated. But it must be recollected that the precipitation (ammonical silver and cupric bisulphite) method was beset with disadvantages. An approximate estimate only of the blood content of uric acid was with difficulty to be achieved even when large quantities were available.

Fortunately, however, our powers of analysis in this direction became greatly enlarged with the introduction in 1913 of the colorimetric method of Folin and Denis.