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

by Unknown

Where, however, polyuria, especially chronic, is due to habitual over-distension, it is in the highest degree probable that it is at least partly due to structural alteration of the kidney. The well-known experiment of Bernard, by which an increased flow of urine was induced by a puncture of the floor of the fourth ventricle, and those of Eckhard on section of the splanchnic nerves, show how it is possible for nervous affections to influence the secretion of urine, though the path or paths of the influence are by no means completely made out.

One of the most noticeable points in the pathology of the more excessive cases of polyuria is the disproportion which often exists between the amount of fluid ingested and the amount discharged, the latter often exceeding the former several times. The source of the excess of water has not been satisfactorily determined, but it is evident from a careful experiment of Watson, repeated by Dickenson, that the body has under some circumstances the power of appropriating water from the atmosphere instead of discharging aqueous vapor through the lungs and skin as usual. In the experiments referred to persons affected with extreme polyuria were weighed immediately after passing water, and again after as long an interval as they were able to restrain their thirst, of course being also without food and under observation, when it was found that the weight had been increased by a number of ounces. In Dickenson's case, weighing thirty pounds more or less, where the amount of urine excreted daily was from seven to nine liters, the gain in weight at several observations was as follows: in three hours, 15½ oz.; in five hours twenty minutes, 19¾ oz.; in three and a half hours, 3¾ oz.

The DIAGNOSIS of this affection rests, in the first place, upon the determination of a permanent increase in the quantity of urine passed considerably above the normal, and, as has been already remarked, may require a measurement of the daily amount—a procedure which it is well to make a matter of routine in any cases where urinary trouble may be present. The increase being found, if it be very great it will only remain to determine whether sugar be present, which will be indicated by the specific gravity and the appropriate chemical tests. Traces of sugar are sometimes found in cases of polyuria which do not present the characteristics of saccharine diabetes, and can hardly be considered to materially affect the character of the disease.

A specific gravity decidedly above normal, with an excessive quantity of urine, is not likely to belong to anything but diabetes mellitus, though the chemical tests should never be neglected. If, however, the polyuria be only moderate, it becomes necessary to exclude surgical affections of the urinary passages, especially an enlarged prostate, often attended with retention and distended bladder. Pyelitis and hydro-nephrosis may also give rise to the same condition of over-activity of the kidneys. The appropriate surgical examinations with the sound may be necessary, but the presence of pus, bacteria, and the epithelium of the urinary passages in the surgical urine, as well as its frequent alkalinity, may direct a very strong suspicion before the sound is used. The age of the patient also will be of considerable weight in this connection.

A point of real difficulty of diagnosis, and great importance for treatment and prognosis, is the distinction between simple polyuria not excessive, but attended by constitutional symptoms, such as impaired nutrition, dyspepsia, and severe headache, from chronic interstitial nephritis, which often makes its appearance with similar symptoms. Mistakes between these two affections have undoubtedly occurred, and can in many cases hardly be avoided except by reserving the diagnosis for a time.

The similarity is rendered still more deceptive by the undoubted occurrence of a trace of albumen or a hyaline cast or two in cases of nervous disturbance, without justifying a diagnosis of progressive renal disease. High arterial tension also is likely to be found in both conditions. Nothing but repeated and careful examinations of the urine and of the circulation, especially at times when the nervous symptoms are less marked, and often a considerable amount of time, can fix the diagnosis.

Hypertrophy of the heart, and even slight dropsy, will undoubtedly be extremely decisive symptoms, but are not likely to occur until after a time when the doubt no longer exists. In other cases it may be highly important to carefully exclude organic cerebral disease before making a diagnosis of simple polyuria.

It is hardly appropriate to speak of a diagnosis from azoturia or phosphaturia, since these conditions are extremely likely to exist coincidently with typical polyuria and to make a part of the same disease. It is of much importance, however, to ascertain their presence with reference to the probable effect of the disease on the nutrition.

In regard to the TREATMENT, it may be remarked, to begin with, that restriction of water, although naturally diminishing somewhat the discharge of urine, does not cure the disease, but, on the contrary, in many cases augments not only the discomfort of the patient, but tends to the dryness of the skin, dyspeptic and nervous disturbances, and emaciation. Patients may recover flesh, strength, and spirits on being allowed to drink ad libitum, even although the inconvenience of excessive urination be thereby somewhat increased. Sufficient food and drink should therefore be allowed, although a patient may be ordered to observe such moderation as will not put his powers of endurance to too severe a test.

Of the drugs proposed, nearly all have offered some prospect of success, and have been accordingly reckoned almost specifics. Opium has in some cases been found as useful in these cases as in diabetes mellitus, and probably, as in that disease, by diminishing the sensitiveness of the nervous system. Valerian and valerianate of zinc, recommended by Trousseau and apparently successful in his hands, have reckoned both failures and successes in the hands of others. Nitric acid, in the dose of from 1 to 5 drachms per diem of the dilute in a large quantity of water, is said to have been highly efficacious in one series of cases.¹² It is given until aching of the jaws and teeth, with some gingivitis, denoting its constitutional action, is produced. It was more successful than any other drug in Marion's case, although the specific symptoms were not produced, the patient being now in good health or free from her trouble. Atropia from its general action in diminishing secretion has been tried, and with occasional alleged success, but with many more failures. Pilocarpine from its action on the skin might be of value in those cases where the skin is very dry, but has no very general applicability.