Amyloid degeneration of the kidneys is not such a common lesion as it used to be, owing to the improvement in the treatment of septic cases. Still, from time to time amyloid disease is still found associated either with phthisis or as a result of long-continued suppuration. There is a considerable clinical resemblance between these cases and those of chronic Bright's disease, and even of granular kidney, but the dietetic treatment of amyloid disease of the kidney is quite different to that of either of these other lesions, and hence it is important that an accurate diagnosis should be made. This is more especially necessary, inasmuch as in cases of phthisis, for instance, both amyloid disease of the kidney and nephritis may exist as complications. In amyloid degeneration the excretory functions of the organ are not compromised to the same serious extent that they are in nephritis, unless the amyloid disease is very far advanced or, as not infrequently happens, the two lesions are co-existent in the same kidney.
One of the most striking effects produced by amyloid disease is albuminuria, and the daily loss of albumin may be very considerable. In some instances, however, the type of urine excreted is more like that seen in granular kidney, being abundant and dilute, and containing but a trace of albumin.
In amyloid disease, as a rule, the renal lesion should not materially influence the dietetic treatment, in other words, the diet ordered should be that suitable for the underlying disease, and no undue stress should be laid on the presence of the renal complication. Much harm may be done by restricting the diet owing to the existence of albuminuria, with the mistaken idea that the diet suitable is similar to that ordered in other forms of chronic kidney disease. It is quite hopeless to attempt to restrict the albuminuria by dietetic measures; both in nephritis and in amyloid kidney a solid diet, containing considerable quantities of meat, may not materially increase the daily loss of albumin, and inasmuch as the underlying disease associated with amyloid degeneration is usually one where there is very great malnutrition, it is obvious that the diet should not be restricted unless there is very urgent necessity, such as the development of uraemic symptoms, or the occurrence of marked renal dropsy; the former is a more important indication for dietetic restriction than the latter.
Thus cases where albuminuria results from amyloid disease should be treated quite differently to any other renal lesion accompanied by albuminuria, since a liberal diet in no way restricted is probably the most suitable, and hence the patient's tastes and inclinations can be allowed far greater play than in other affections. Again, there is not the same objection to the use of stimulants in amyloid disease, and they may be ordered where it is considered advisable either from a point of view of the general weakness, or where it is thought advisable to give them from the point of view of aiding digestion or increasing appetite.