Definition.—The presence of albumin in the urine.
Etiology.—The terms albuminuria and Bright's disease were used synonymously for a number of years, and to detect albumin in the urine was proof sufficient for a diagnosis of nephritis.
It is now recognized, however, that there are several conditions other than nephritis giving rise to albuminuria, several of which are innocent, provided they are not persistent.
The presence of albumin in the urine, in all probability, indicates some change, however slight and transient, in the epithelium of the glomeruli or the capillaries of the tuft, which permits the escape of the normal constituents, serum-albumin and serum-globulin, from the vessels into the renal tubules.
The principal causes giving rise to albuminuria are acute and chronic congestion of the kidneys, acute and chronic nephritis, the various degenerations of the kidneys, the toxin of scarlet fever, diphtheria, typhoid fever, measles, influenza, and numerous infectious diseases, certain blood changes that occur as the result of arsenic poisoning and poisoning from other minerals, and of certain diseases, such as scurvy, leukemia, syphilis, and others of like character. Pregnancy and certain lesions of the nervous system, as epileptic seizures, apoplexy, etc., may also be attended by albuminuria. We may divide albuminuria, for convenience, into functional and structural, eliminating from the latter those cases not due to nephritis.
Paroxysmal or Cyclic Albuminuria.—This variety is characterized by a regular rise and fall in the quantity of albumin during the twenty-four hours. Usually the amount is small, with but few if any casts.
The albumin appears shortly after rising in the morning, gradually increases during the day, grows less on lying down, and disappears during the night, to reappear the following morning.
The quantity varies according to the mental or physical exertion of the patient, and the character and quality of the food taken.
It occurs mostly in young men whose general health has become impaired. These patients are generally enemic, lose flesh and strength, suffer with headache and general languor, disorders of the stomach and bowels, and are inclined to be hysterical. Where these conditions have existed for some time, it is often quite difficult to diagnose the functional from the structural form.
Dietetic Albuminuria is that form where albumin appears in the urine after the ingestion of certain articles of food, notably eggs, cheese, and pastry, or any full meal, especially where digestion is faulty or where severe exertion takes place immediately after a meal. The quantity is usually small, with but few and only temporary casts.
Neurotic Albuminuria is that form which follows periods of great emotional excitement, hysteria, and severe mental strain. Epileptic seizures, apoplexy, tetanus, and injuries of the head, also give rise to it.
Albuminuria Following Exertion.—This is due to congestion of the kidneys, and appears after severe or prolonged exertion. It is often found in the urine of athletes after contests of running, rowing, or any of the various contests where prolonged strength is required. The quantity is usually small, and disappears after a few hours of rest, to return again when the same conditions again appear.
The Blood Changes, as seen in syphilis, lead, mercury, and arsenic poisoning, severe anemia and puerperal eclampsia, when not due to nephritis, give rise to albuminuria.
Febrile Albuminuria.—The various febrile and inflammatory diseases may give rise to slight albuminuria. The presence of albumin in the urine is due to some change in the epithelium of the glomeruli, caused by the toxins of the fever, and although there is a cloudy swelling, there is no structural change.
This may accompany diphtheria, typhoid fever, the eruptive fevers, tonsillitis, and like diseases.
While these various forms of albuminuria are not regarded as serious, yet if persistent, they should be regarded unfavorably, as they usually lead to structural changes.
Diagnosis.—The diagnosis of albuminuria is made by finding albumin in the urine, by one of the several tests described. The differential diagnosis, however, will require a more careful study. In renal or structural albuminuria, the quantity is persistent, usually large, and contains a larger per cent of tube-casts. There are also symptoms of dropsy, cardiac derangement, and more or less anemia.
In functional albuminuria, the quantity is small, with but few casts, and is not constant.
Tests for Albumin.—The urine to be tested should be free from any morphologic constituents, and should therefore always be filtered. Care should be taken that it be free from leucorrheal and menstrual discharges. Two samples should be taken; one before breakfast and after a night's rest, the other at the close of the day.
1. Boiling Test.—This is the most common, easy, and reliable test for albumin. Fill a test-tube about one-third full of urine: if neutral or alkaline, add one or two drops of acetic or nitric acid. Hold the tube slanting, that the heat may strike the upper portion of the urine, and bring to a boiling point. If albumin or the phosphates be present, the upper portion becomes turbid, which is clearly shown against the clear urine in the bottom of the tube. Then add a few drops of nitric acid, which will thicken the turbidity if albumin be present, and clear it if it be absent.
2. Heller's Nitric-Acid Test.—This requires a little more care in the test, and is no more reliable. It is as follows: put a little nitric acid into the test-tube, and then carefully pour a little urine down the side of the tube; as it comes in contact with the acid, a white ring is formed at the point of contact. Uric acid, urates, and certain coloring matters, form a pink or red zone, which is just above the junction of the two liquids. Hemialbumose will give the same white zone, but does not respond to the boiling test as does serum-albumin.
3. Johnson's Picric-Acid Test.—Place a little urine in a test-tube, and carefully place a few drops of a saturated watery solution of picric acid upon the top of the urine; if albumin be present, a turbidity or white zone immediately forms at point of junction. Heating strengthens the evidence already manifest.
4. Ferrocyanid-of-Potassium and Acetic-Acid Test.—Fill a test-tube one-third full of urine, and add a few drops potassium-ferrocyanid solution. After thoroughly mixing the urine and the reagent, add ten to fifteen drops of acetic acid. If albumin be present, a cloudiness more or less pronounced takes place, depending upon the amount of albumin present. As this precipitates all forms of albumin, either acid or alkaline, and does not precipitate rnucin peptones, phosphates, urates, vegetable alkaloids, or the pine acids, it becomes a very reliable test.
5. Magnesium Nitric Test.—To five volumes of the saturated solution of sulphate of magnesium add one volume of strong nitric acid. Fill a test-tube one-third full of this solution, and with a pipette allow the urine to flow down the side of the tube; at the point of contact a cloudy ring will form.
6. Quantitative Test.—To determine the proportion of albumin per thousand, Esbach's albuminometer will be used. This tube bears two marks: one, U, indicating the point to which the urine must be added; and one, R, the point to which the reagent is added. The lower portion of the tube up to U bears a scale reading from one to seven. The tube is filled to- U with filtered albuminous urine, and the reagent added till the point R is reached. The tube is then closed with a stopper, inverted twelve times, and set aside for twenty-four hours. At the expiration of this time serum-albumin, serum-globulin, and albuminose, as well as uric acid and creatinin, will have settled down, when the amount per mille, in grams, may be directly read off from the scale. The solution used is composed of ten grams of picric acid and twenty grams of citric acid dissolved in 1,000 c. c. of distilled water. (Simon.)
Prognosis.—This depends entirely upon the cause and length of time that albumin has been found in the urine. Albuminuria due to fever and hemic changes is nearly always transient, and disappears with the subsidence of the fever.
If the patient be a young man, and there is no increased arterial tension, the albumin may disappear spontaneously after a few months' time. Occurring in a patient past forty years of age, with increased arterial tension, it would indicate a more serious kidney lesion.
In cyclic and dietetic albuminuria the prognosis is generally favorable. In all cases of persistent albuminuria, however, there is in all probability glomerular changes that are apt to lead to structural changes. If the kidneys are affected, and there be increased arterial tension, and tube-casts be present, the prognosis must be guarded, and if the patient be an applicant for insurance, his application should be refused.
Treatment.—The treatment is largely dietetic and hygienic. The patient should eat sparingly of meats and eggs, the principal diet consisting of vegetables, fruits and milk. Exercise in the open air, short of weariness, should be taken, and no severe work, either mental or physical, allowed. Drop doses of Howe's acid solution of iron, when an acid is indicated by the red tongue, will give favorable results.