ADDED UREA AND SALT TEST
Patient is given 75 grams of protein, 4 grams of sodium chloride, and 1500 c.c. of water, with a caloric value of from 2000 to 2200 calories. After the output of fluid, salt and nitrogen reaches an equilibrium on this diet on one day 10 grams of additional salt is given and several days later the patient receives 20 grams of urea. This order may be reversed. The daily output of urine, salt, and nitrogen is determined and charted. After the salt and nitrogen is added to the diet in normal individuals, their excretion after forty-eight hours returns to its previous level. In diseased kidneys this may not be the case.
Value of Tests.—Thus it is seen that in these tests for kidney functions, an effort is made to determine the extent of damage wrought by the disease upon the renal organs and the manner in which they react under definite circumstances. However, it is not so simple as it would seem to formulate a dietary based on the findings resulting from the renal tests. Notwithstanding this, these tests are coming more and more into use, both in hospitals and private practice, and a nurse must understand just how they are carried out, and must realize that unless her part is performed with absolute accuracy the entire value of the test will be obliterated. Too much stress cannot be laid upon this phase of the test, if it is to be of any value whatsoever in determining the condition of a diseased kidney.
CHRONIC INTERSTITIAL NEPHRITIS
This form of nephritis is more insidious in character, developing more slowly and manifesting different characteristics, than those seen in some of the other types already mentioned. The condition is, as a rule, associated with heart symptoms and high blood pressure. The blood shows an increase in urea and other end-products of protein metabolism, whereas there is no manifest change in the metabolism of salt or water. The great increase in volume of urine voided would show an inability on the part of the kidneys to eliminate a highly concentrated urine. This hypothesis is further demonstrated in the urine tests.
Urinalysis.—Upon analysis the urine in these cases shows less albumen and fewer casts than found in other types of nephritis. The disease is manifested by slight headache, gastric disturbances, and a frequent desire to urinate.
Dietetic Treatment.—The treatment here depends upon the extent of the impairment of the functions of the kidney. If the damage is not extensive and the diagnosis has been sufficiently early to insure prompt improvement upon treatment, the diet is so directed as to prevent the occurrence of any of the acute symptoms. The patient is warned against overeating and drinking, over-exercise and nervous excitement. When it is possible, a change to a warm, dry climate is advisable with more rest and sleep and less work and worry. He is advised to eat less at meals and if hungry to eat a light lunch of milk or buttermilk with crackers in the mid-morning. The same dietary precautions must be taken in these disturbances as in other nephritic conditions, keeping always in mind the fact that the kidneys are the chief organs of excretion in the body, and through them must pass the majority of all end-products of nitrogen metabolism.
Limiting the Nitrogen.—The nitrogenous foods cannot be eliminated entirely, especially if, as is often the case, the individual suffers from chronic nephritis and is up and about attending to business; but they can be judiciously regulated in the diet. All such foods as fried foods, rich pastries, rich sauces and gravy, spices of all kinds, tea and coffee, celery and asparagus, must be avoided.
Limiting the Fluids.—von Noorden limits the amount of fluid to 1¼ liters per day. This does not include the water content of the various foodstuffs. He advises a period of observation to determine the amount best suited to the condition of the patient and reducing this amount from 250 to 150 c.c. a day until the desired quantity is reached. He advises a drinking day once a week, allowing the patient to drink as much water as he likes.
Development of Uremia.—Whenever evidences of uremia appear the treatment must be changed to meet the condition. It is necessarily more strenuous than that used ordinarily in the chronic nephritis. If the uremia becomes positive, then the treatment laid down for acute nephritis already described must be at once instituted. The patient must be put to bed at once and every effort made to assist the body in getting rid of the causes.