FOOTNOTES:
[106] “Some Gastro-intestinal Notes,” “The Medical Clinics of North America,” Vol. I, No. 1, pp. 192-193, by Thomas R. Brown, Johns Hopkins Hospital.
[107] See Formulas for Nutrient Enemas, p. [145].
[108] See Albumen Water with Brandy, p. [141].
[109] “Diet in Health and Disease,” p. 555, by Friedenwald and Ruhräh.
CHAPTER XVII
URINALYSIS
The importance of the kidney functions has been clearly demonstrated. Urine, which is the fluid secreted by these organs, is one of the most important sources of information, not only as to the manner in which the body utilizes food in health, but as an index to certain pathological conditions, the processes of which are more or less indicated by the products excreted in the urine.
Function of the Kidneys.—The kidneys, as has already been stated, furnish a means by which the greater part of the waste products of the body are eliminated and in addition to this function they adjust the salts in the body. In an early chapter the function of the salts in food was explained. A certain amount of these substances, we know, is absolutely necessary to carry on the work in the body, but harm comes when a surplus is retained in excess of that which can be used in performing the various processes. Consequently the function of the kidneys to adjust the salts balance is by no means their least important one.
Elimination of the Toxins.—The toxic substances manufactured in the body and those resulting from bacterial action upon unabsorbed proteins are likewise eliminated in the urine. Thus it can be readily understood how necessary it is to keep these organs in good repair, that they may continue their work in an efficient manner.
It is necessary from a pathological standpoint for the nurse to understand the making of some of the simpler tests, that she may simplify her own work and that of the physician.
Excretion of Carbon Dioxide and Water.—We have already spoken of the combinations of carbon and hydrogen compounds. These substances being oxidized, the carbon dioxide produced is eliminated by way of the lungs and the water is excreted partly by way of the lungs and skin, but chiefly by way of the kidneys.
Oxidation and Excretion of Nitrogenous Substances.—When the nitrogenous substances are oxidized, the used-up oxygen products are eliminated by the kidneys in the form of urea and more or less highly oxidized substances, such as ammonia and other salts, purin bases, and creatinin.
Uric Acid, the chief of the oxidation products of nucleoproteins, is produced in the body and from food, and is always in the urine, being one of its normal constituents. It is only when this substance is in excess in the urine that a pathological condition is indicated.
Examination of the Urine, then, is made for several different purposes: (1) to ascertain whether the kidneys are doing their work properly; (2) to find if the kidneys, or any part of the urinary tract, are either temporarily or permanently diseased; (3) to be able to judge from the various substances in the urine whether there is any abnormal process taking place in the body.
Tests.—In the examination of the urine for the above purposes, certain definite tests are made. These tests differentiate between the abnormal and the normal.
(1) Color.
(2) Amount in twenty-four hours.
(3) Odor.
(4) Specific gravity.
(5) Reaction, acid or alkaline.
(6) Albumen, indican, acetone bodies.
(7) Sugar.
(8) Microscopic examination for casts, cells, bacteria, etc.
The Color of normal urine varies, especially with the amount voided.
The variations in color range from the pale straw color of individuals who are voiding large quantities to the deep lemon or amber of those who void much less.
Pathological conditions are indicated to a certain extent by the color of the urine. Fevers heighten the color, small quantities of blood cause a smoky appearance, while bile changes the color of the urine to a greenish yellow.
Precipitates in the Urine.—When the urine has been allowed to stand for a time there is sometimes a brick-red deposit due to the precipitate of urates. This disappears upon heating and is not an evidence of any diseased condition.
Turbidity of Urine.—The turbidity of fresh urine then is the only kind which need be considered, since standing in the cold often brings about this condition, due to the growth of bacteria and deposits of both phosphates and urates.
Requirements in Testing Urine.—Urine to be tested should be fresh, and when it is not possible to make the examination at once it should be preserved with chloroform, or some other harmless preservative, until ready to use.
Bacteria in Urine.—The changes due to bacterial growth in the urine are manifested not only by the turbid character of the urine but also by the odor of ammonia.
The Amount of Urine.—The amount of urine voided in twenty-four hours varies with the individual in health as well as in disease. Many individuals void a great quantity during the twenty-four hours, chiefly because they drink a great quantity of water and other beverages. The average amount of urine passed in twenty-four hours by an adult, or a child over eight years, is from 1000 to 2000 c.c. It represents from 60% to 70% of the amount of water ingested.
Collecting the Urine for Testing.—In measuring the urine it is necessary to begin collecting it after the bladder has been emptied the first thing in the morning. The patient should void just before the end of the twenty-four-hour period to be sure that the amount formed by the kidneys during this time is accounted for.
Diseases in Which Urine Is Diminished.—In certain diseases the amount of urine passed is diminished. This is found to be true in diarrhea and dysentery, when water is lost in the feces, in hemorrhage from any part of the body and from vomiting. It is likewise at times the case after abdominal operations and in nervous conditions, such as hysteria. The urine is diminished when there is an organic obstruction in the urinary tract and certain obstructive diseases of the heart, the lungs and the liver. In these latter cases, there is seen to be a retention or suppression of urine. In both acute and chronic nephritis and in certain fevers, the bladder at times must be emptied by means of a catheter. At other times, the condition is relieved as far as possible by limiting certain articles of food in the diet. At any rate, these points must be kept in mind when examining the urine.
Effect of Food upon the Urine.—The odor of normal urine is changed after eating certain foods, such as onions and asparagus. In disease, the odor of urine has a distinct value as a means of diagnosis; cystitis gives a foul odor, certain bacteria bringing about a decomposition in the urine and giving rise to an odor of putrefaction. In cases where there is a fistula connecting the bladder and rectum, the urine has a fecal odor.
Specific Gravity of Normal Urine.—The density or specific gravity of urine means the weight of any volume of urine as compared with that of equal volume of distilled water. The specific gravity of normal urine varies from 1012 to 1024, that is, in a thousand cubic centimeters of urine there are found from 11 to 18 grams of solid material. In health it is necessary to know the amount of urine passed in twenty-four hours, to be able to judge whether the amount of solids is too high or too low.
Specific Gravity of Diabetic Urine.—In conditions like diabetes mellitus, where there is a wastage of sugar taking place in the body—that is, instead of being oxidized to carbon dioxide and water and glucose, the sugar is passing into the urine without completing its oxidation—the specific gravity rises in these cases to 1030 and over, showing distinctly that a greater amount of solid material is in the urine than is present normally. In chronic Bright’s disease and diabetes insipidus, the specific gravity is low.
Method of Determining Specific Gravity.—The specific gravity is determined by the use of an instrument known as a urinometer. The urine is poured into a tube and the urinometer is dropped into it. The different figures are marked upon the stem of the instrument and it is a simple matter to read off the figures of the level to which the stem sinks.
Reaction to Litmus.—In a former chapter it was stated that normal urine was, as a rule, acid, that is, it turns blue litmus red. Certain diseases render the urine alkaline. A like result is brought about upon the ingestion of sodium citrate or bicarbonate of soda. Urine which stands and becomes decomposed is alkaline in reaction, due to the bacterial action, with the production of ammonia.
Albumen in the Urine.—The presence of albumen in the urine is important, since normal urine does not contain this material in quantities sufficient to be recognized by ordinary tests. Hence in disease its presence is an indication of pathological processes taking place either in the kidney or the urinary passages. The chief abnormal condition indicated by the presence of albumen in the urine is nephritis. Traces of albumen may occur in patients with fever or a heart weakness. Blood and pus in the urine likewise indicate albumen. When the nephritic condition is chronic, the kidneys themselves are diseased and the presence of albumen may be in traces only, while during the acute attack large quantities may be passed, but the urine will clear up after a time.
Benedict’s Qualitative Sugar Test.—Boil 5 c.c. of Benedict’s solution; add 8 drops of urine to be examined; hold the tube over the flame and allow to boil vigorously for 3 minutes and set aside to cool of itself. In the presence of sugar the entire solution will be filled with a precipitate which may be greenish, yellow, or red, according to the amount of sugar present. When the percentage of sugar is low (under 0.3%) the precipitate will form only upon the cooling of the solution. If there is no sugar present, the solution will either remain clear or show a slight turbidity, due to the precipitation of urates. The nurse must remember that to be useful the test must be made accurately. There must never be more than 10 drops of urine and 8 drops is the usual quantity. The boiling must be vigorous and the solution allowed to cool spontaneously.
Fehling’s Test for Sugar.—Fehling’s alkaline solution and Fehling’s copper solution must be kept in separate bottles until ready for use. Then about 2 c.c. of Fehling’s alkaline solution is poured into a test tube and 2 c.c. of Fehling’s copper solution is added. This is diluted with hydrant water to 8 c.c. Half of this quantity is sufficient for the test. The upper half of the solution is boiled over flame (gently agitated while heating), and while still boiling a few drops of urine are added. If no change appears, it is boiled again and a few drops more of urine are added. If a reddish precipitate appears, sugar is present. The chemical reaction taking place is the reduction of copper sulphate to cuprous oxide. Sometimes a partial reduction occurs when urates are in excess, but once having seen the real reduction, a partial one cannot mislead the examiner.
Haines’s Test.—Pour 1 teaspoonful of Haines’s solution into a test tube and boil gently over a Bunsen burner; add 6 or 8 drops of urine and again heat to boiling. A yellow or red precipitate will indicate the presence of glucose.