A system of practical medicine. By American authors. Vol. 4

by Unknown

Munn¹⁵ found albumen in small quantities in 11 per cent. of cases presenting themselves for life insurance, supposing themselves healthy and having no lesions of heart or lungs. It is not stated whether casts were found in these cases or not, and their value as representing healthy persons cannot, it is obvious, be correctly estimated until some time has elapsed. It is well known that renal lesions may be exceedingly slow in their progress, and it is by no means improbable that a part of these cases may have been really in the early stages of a chronic form of Bright's disease. Albumen has been found in the urine of boys and adolescents, as well as in that of healthy soldiers, tested immediately after rising: in most of these cases the amount was extremely small. Certain conditions, moreover, may greatly increase the proportion of cases in these same classes in which albumen is present. Thus, fatiguing exercise will bring it on in some persons, and the urine of a body of soldiers if examined late in the day after severe drill shows a much larger proportion of albuminurics than if examined after rising. The urine of the pedestrian Weston is said to have contained not only albumen, but casts. It is certainly not true that fatiguing exercise will cause albuminuria in everybody, and it is not claimed, even by those who report these and similar cases, that they prove albumen to be a normal constituent. Some of the cases are distinctly described as delicate without being actually ill. Cases have been reported where cold bathing has been followed by temporary albuminuria. Here it is in the highest degree probable that a disturbance in the circulation is produced by contraction of the cutaneous arterioles; and it is possible that we may find in this increased sensitiveness of certain persons an explanation of the occurrence of acute dropsy as a sequel to scarlatina or as the result of exposure in only a small proportion of the cases where the exposure takes place. It is hardly necessary to admit, on the basis of these observations, that albumen is a constituent of healthy urine, although this may be shown at some future day by still more delicate tests, but simply that the renal circulation may in certain sensitive persons be sufficiently influenced by slight and transient causes to permit albumen to pass into the urine. It is the almost unanimous conclusion of practical writers, taking fully into the account these recently-ascertained facts of albuminuria in alleged health, that the presence of albumen in the urine in sufficient quantity to be detected by any of the ordinary tests is a decidedly serious symptom.

¹⁵ New York Medical Record, xv. 297.

The influence of many well-recognized pathological states in bringing about venous stasis, and that delay of the blood in the renal—and more especially the Malpighian—vessels which seems the most essential factor in the secretion of albumen, is well known, and its recognition is of much importance in diagnosis and prognosis, since the unfavorable signification of albuminuria in certain cases is liable to be overrated, and a diagnosis of chronic renal disease made to depend upon symptoms which really belong to some other affection. How far alteration in the capillaries and epithelium is in each case concerned in the production of albuminuria it is often impossible to say, since any alteration in these elements which can be observed after death is almost certain to be complicated with lesions which can disturb the local circulation.

Cardiac obstructive disease is very likely to be accompanied by albuminuria, and the state of the kidneys by which this condition is brought about is undoubtedly venous congestion. The urine in a case of this kind is usually scanty, of high specific gravity, high colored, often with a deposit of urates, while the albumen appears in small quantity. A few hyaline casts are not infrequently seen, and do not materially increase the gravity of the prognosis so far as renal disease is concerned. The kidney which furnishes this urine is usually a little harder and a little denser than normal, but with a nearly normal microscopic structure, exhibiting but little more than capillaries well filled with blood, and in the interior of some of the tubes casts similar to those found in the urine during life.

Doubt may occasionally arise as to the diagnosis between a congested kidney consequent upon valvular disease of the heart and an interstitial nephritis with hypertrophy of the heart. In the latter case, however, the urine, although containing albumen, is usually much more copious and of low specific gravity. Diminished power of the heart without valvular lesion may have as a consequence albuminuria which disappears if the heart recovers its vigor.

In many of the cases in which albumen appears in the urine temporarily it is not easy to say whether an actual nephritis may not be present, though not sufficiently severe to give rise to other symptoms.

In almost any febrile disease of sufficient intensity albumen is often found, and when such a case terminates fatally without renal symptoms, the condition of the kidneys, consisting in more or less granular degeneration of the epithelium, is often spoken of as parenchymatous nephritis. If it is correctly called so, it is certainly very different from the idiopathic form, whether acute or chronic, since it is very rare for typhoid fever, for example, either to present the symptoms of acute nephritis during life or to terminate in chronic Bright's disease. In scarlatina, and rarely in other fevers, a distinct nephritis is present, but a degeneration of structure sufficient to produce albuminuria is in many instances a result merely of a high temperature.

Many applications to the skin produce albuminuria, but in almost all, if not all, of these an actual nephritis has been found to exist. The same is true of poisoning with strong acids, phosphorus, and arsenic.

A very important form of albuminuria is that found during pregnancy, more frequent with a first child or with twin pregnancy, and often associated with other symptoms of nephritis. It is probable, however, that in many instances it is a result of impeded abdominal circulation, although it is very rarely that the gravid uterus can press directly on the renal veins. In the severer cases a well-marked parenchymatous nephritis exists; but it should be distinctly borne in mind that if every instance of albuminuria in pregnancy is due to nephritis, it is certainly a form of the disease which may lead neither to severe symptoms nor to chronic disease. On the other hand, the appearance of albumen in the urine of a pregnant woman, though not necessarily calling for active interference of any kind, should always be a danger-signal, and put the physician on the lookout for other indications of actual renal disease.

In many nervous affections albumen may be found in the urine. It can be produced, as was shown long ago by Bernard, by a puncture in the floor of the fourth ventricle near to the point where a similar puncture gives rise to diabetes. Lesion of the cerebral peduncles, section, destruction, or irritation of the spinal cord, and irritation of the renal nerves are also causes of this symptom. It is by no means difficult to account for this phenomenon by the changes which take place in the renal circulation under influence of the vaso-motor nerves which originate or pass through the peduncles, pons, and spinal cord, although it is highly probable that similar results might follow irritation transmitted from a distance. These facts are not without practical importance, for they give rise to very considerable chances of error in diagnosis; as, for instance, where a patient suffering from severe headache, with possibly gastric symptoms, is found to have albumen and casts in his urine, which is also copious and of low specific gravity. It might not be easy to decide that such a case was not one of interstitial nephritis with symptoms far from unusual, and yet it might perfectly well be a cerebral tumor. The diagnosis would demand a thorough search for other symptoms, such as double optic neuritis on the one hand, as indicating cerebral disease and cardiac hypertrophy, with high arterial tension on the other, as connected with nephritis. A careful consideration of the order of their occurrence is also desirable.