j. Water (Sweating Cures) - Should Be Avoided In Renal Disease

I have already said that water is very badly excreted by the kidneys when they are acutely diseased and frequently also in sub-acute and sub-chronic forms of nephritis; individual cases differ greatly in this respect. On the other hand, there is no substance which excites the function of the kidneys so powerfully as does water. If active diuresis is induced by abundant water drinking, other excretory substances that may have accumulated in the body are usually flushed out at the same time. I say "usually" because this does not always happen. I can recall, several cases of chronic nephritis in which diuresis suddenly became more free, but in which at the same time the quantity of solid urinary constituents and especially the quantity of urea did not increase.

From the standpoint of prophylactic therapy that we are discussing, the limitation of water seems to be indicated in cases where the kidneys refuse to excrete it, in cases where diuresis is not increased by water drinking, and in cases where the water ingested only serves to augment the oedema and hydraemia. A condition of hydraemia must be regarded as a constant source of irritation to the kidneys, and the problem that confronts us is to prevent excessive stimulation of these organs as much as possible.

It is customary to permit patients with acute nephritis and allied conditions, even if there is much oedema and a scanty flow of urine, to drink large quantities of fluid (milk and mildly alkaline waters). The generous supply of water is expected, as it were, to forcibly overcome the resistance offered by the kidneys to the elimination of excretory substances. It is my impression that harm is occasionally done in this way; the oedema increases from day to day, the strength of the heart diminishes, respiration becomes impeded, and nausea and vomiting become more frequent. Under such conditions, that do not of course obtain in every case of acute nephritis, I have often been forced to reduce the quantity of fluid and of food in general to the smallest possible amount. In these cases the patients are often strong and in good general condition and well able to bear a great diminution in the amount of food; they may even stand total abstinence from food for a few days. Patients are benefited more in this way than if they are persuaded or even forced to take food; for we must always remember that a large part of the food will be vomited. As a matter of fact patients with severe nephritis absorb extremely little of their nutriment; only water is demanded with eagerness, - this is remarkable in view of the fact that the tissues are more than saturated with water. In cases of this kind in which only small quantities of nutritious food can be tolerated I have frequently seen decided improvement follow the restriction of water also.

This was most marked in the case of a boy of eleven years whom I treated in the summer of 1894 for acute nephritis of unknown origin. The treatment consisted of vapor baths repeated daily. Very marked oedema was present.

On the tenth day, although diuresis was not yet markedly increased, the patient bitterly complained of thirst, the general condition had decidedly improved, and diminution of the cedema was noticed for the first time; from the thirteenth day on it decreased rapidly, and on the eighteenth hardly a trace remained. Further convalescence was undisturbed.

So great a diminution of food and drink as was ordered for several days in this case cannot be enforced for any length of time, nor is it permissible. Usually it is a difficult matter even to slightly restrict the use of fluids, for all foods that are permissible in this stage of nephritis contain much water; milk, of course, especially.

We are happily in a position to obviate this difficulty in another way, vis. - by making the patient sweat. The really great value of diaphoresis¹ in acute nephritis depends, in my judgment, upon the withdrawal of water from the blood and tissues. It is questionable whether in addition certain poisonous substances which ought really to be excreted by the kidneys are eliminated in the sweat and the kidneys spared in this way. Although this has been claimed for centuries, no one has as yet proved that it is true. The perspiration of nephritic patients contains only traces of urea (the maximum is about 1 to 1.3 g. in the total quantity of a profuse sweat), and in addition a barely determinable trace of uric acid. The remaining constituents are harmless substances : water, salt and small quantities of organic fatty acids. In spite of strenuous efforts to detect poisonous substances in the sweat none have ever been found. I see no necessity for formulating such doubtful hypotheses on the excretion of poisons by means of diaphoresis, when we can explain the curative effect of this procedure so much more simply by the fact that it relieves the kidneys of the task of excreting water.

¹As to the diaphoretic method, I prefer not to give the patient a hot bath and wrap him in warm blankets, but to expose him to the rays of electric lights without a previous bath. For this purpose I use portable tunnels that can be applied to any bed; to the inner surface of this apparatus some 6 to 10 incandescent globes are attached. The procedure calls forth a large amount of perspiration and spares the patient very much more than does the hot bath followed by the pack; the latter requires more than double the amount of time to produce active sweating.

No matter how great the loss of water through the skin may be, the question arises as to whether it is sensible to allow the patient to drink freely on the one hand, thus introducing large quantities of water into the body, while attempting on the other to equalize the harmful increase of hydraemia and of oedema thus caused by instituting so exhaustive and so violent a method of treatment as diaphoresis. That is really beating about the bush. If by sweating our patient we really succeeded in getting rid of poisonous substances that would otherwise be retained in the body and would unduly irritate the kidneys or poison the organism, this troublesome procedure would not only be justified but necessary. But, as stated above, this is by no means the case, and it seems doubtful whether we are justified in relying upon diaphoresis to such an extent as to allow nephritics with oedema to drink water freely, or even, as is generally done, to administer hot tea and mineral waters in order to increase sweating. From practical experience I am opposed to this procedure in so far as the first stage of nephritis is concerned. I believe I am justified in taking the stand that it is better not to give as much water as possible for the purpose, as the saying is, of exciting diuresis; because exciting diureses is synonymous with irritating and consequently harming the diseased kidneys. According to my way of thinking it is much better to give as little water as possible, that is, as small a quantity as is commensurate with the patient's demand for liquid nourishment, and at the same time not more than is needed to quench his thirst. This will always be at least one and a half-to one and three-quarters liters per day. If in spite of the fact that the use of water is restricted as much as possible diuresis fails and the oedema increases, diaphoresis must naturally be resorted to. This plan of regulating the ingestion of fluid seems to me the most suitable method of shielding the kidneys and of preventing the excessive development of dropsy.

In later stages of acute nephritis we may pursue a different course. Whenever diuresis increases of its own accord in cases of nephritis with oedema, or whenever diuresis, as we frequently see, is marked from the onset and at the same time oedema is slight, we need not diminish the quantity of water. The kidneys in these cases are capable of performing the work which the free ingestion of water imposes upon them. There are even certain advantages in allowing the patient to drink much water during the convalescent stage of acute nephritis, because the rapid flow of water coming from the glomeruli flushes out the products of coagulation, extravasated blood cells and degenerated kidney epithelium contained in the tubules. In addition, the solid constituents of the urine reach the kidneys in more dilute solution and are consequently more readily eliminated and produce less irritation of the diseased organs, which still require a certain amount of care, than if they were in a more concentrated solution. From this point of view it seems to me very extreme and narrow minded to prolong diaphoretic treatment in spite of free diuresis as long as albuminuria persists. Many physicians inclined to dogmatism have come to have firmly fixed in their minds the idea that sweating is a direct cure for albuminuria or even for inflammation of the kidney. As to this there need be no words wasted. Diaphoresis is directed against hydraemia and oedema. It is a sensible procedure and of the utmost value during the period of anuria and oliguria; later, however, when diuresis is profuse and oedema has disappeared, diaphoretic procedures can, to say the least, be dispensed with. They are unnecessary if the quantity of ingested fluid is regulated according to the functional powers of the kidneys and if care is taken to preserve the proper proportions between the fluid ingested and that excreted.