Part 37

=Oxalic Acid= (C{2} H{2} O_{4}) appears to be secreted in small amount by healthy kidneys and it may also come from the splitting up of uric acid after secretion. It is augmented by feeding agents rich in oxalic acid (beets, fresh beans, asparagus, tomatoes). Pathologically it abounds in certain indigestions, and is associated with lameness and emaciation. Test: Add lime water to the urine, and the white oxalate of lime is precipitated.

=Allantoin= (C{4}H{6}N{4}O{3}) is found in the urine of sucklings (calves) during the first few weeks of life, in pregnancy and when on a meat diet. It diminishes with the increase of vegetable food.

=Xanthin= (C{5}H{4}N{4}O{2}) is found in urine as a result of imperfect oxidation of nitrogenous matters especially, which would otherwise pass into uric or hippuric acid. Its immediate antecedents in such transformation are guanin and hypoxanthin or sarkin. It is a rare constituent of urinary calculus.

=Hypoxanthin= (C{5}H{4}N_{4}O) is produced from fibrine in gastric and pancreatic digestion and in putrefaction, and is especially abundant in leucæmic subjects.

=Cyanuric Acid= (C{20}H{14}N{2}O{6}) occurs in dog’s urine.

=Leucin= (C{6}H{13}NO{2}) and =Tyrosin= (C{9}H{11}NO{3}) are products of pancreatic digestion of proteids, and the former occurs normally in the spleen, thymus, thyroid, liver, salivary glands, and urine. Both are present in large amount, in the urine, in acute atrophy of the liver. Test for leucin: Evaporate carefully to dryness with nitric acid: the residue, if leucin, will be almost transparent and turn yellow or brown on the addition of caustic soda. If now heated with the soda it forms an oily drop. Test for tyrosin: treated with strong sulphuric acid, gently warmed and chloride of iron added, it gives a violet color.

=Albumen= is an important morbid constituent of urine, which appears in a great variety of diseases (nephritis, pneumonia, epilepsy, anæmia, leucæmia, diabetes, hæmaturia, hæmoglobinuria, hydræmia, infectious lung diseases, cardiac obstruction, venous stasis in the kidney, dermatitis, burns, lesions of the crura cerebri, floor of the fourth ventricle, spinal cord, or renal vaso-motor nerves). It also occurs after violent exertion, in poisoning by strong acid, phosphorus, arsenic, lead, mercury, opium or alcohol, and when an excess of albumen is injected into the blood. All forms of albumen may enter the urine, but the most common are serum albumen, globulin of serum, propeptone and peptone. A simple test is to acidulate the urine with acetic acid and boil: if the precipitate does not dissolve on addition of nitric acid, it is albumen. Sulphosalicylic acid added to the urine will cause a precipitate in urine containing only ¹⁄₅₀₀₀₀ of albumen.

=Glucose= (C{6}H{12}O_{6}) is often normally present for a short period in small amount after a full meal of farinaceous material. It is permanently present in excess in glycosuria, which may result, among other conditions, from diseased liver, punctured medulla, suppression of milk secretion on weaning the calf, oil of turpentine, nitrobenzole, nitrotoluol or amyle nitrate. Test: Add yeast to the urine and keep at 15° to 20° C. when if glucose is present, it becomes cloudy and gives off carbon dioxide, or add a little caustic potash solution, and a few drops of cupric sulphate solution until it is blue: then heat and a red precipitate of cupreous oxide is thrown down. The amount gives the ratio of glucose. Uric acid, hypoxanthin or mucus causes brown precipitate in the absence of glucose: peptone, creatin, creatinine, pepsine and urinary pigment prevent its formation though glucose be present.

=Bile Salts and Pigments= are present in excess in cases of icterus, where these characters may be studied. See Icterus.

=Blood and Hæmoglobin in Urine.= In a variety of diseases (anthrax, hæmaturia, nephritis, Texas fever, hæmoglobinuria, etc.) blood or blood coloring matter escapes in the urine. When blood escapes one finds the reddish color, and under the microscope red globules, normal or crenated (especially in alkaline urine), free, aggregated in masses, in small clots, or embedded in casts of the uriniferous tubes. Under the spectroscope the spectrum shows two dark absorption bands, one in the yellow and one in the green. When the color is due to hæmoglobin the urine shows under the microscope numerous masses of amorphous brown pigment, and the spectrum shows one dark line in the yellow, and three others less deep, (but one of them very broad) on the limit of the green and blue. Urine which contains the elements of blood is usually turbid and thick or glairy, by reason of the presence of salts, albumen and fibrine. There may also be crystals of urinary salts (calculi), fragments of broken down tissue (tumors) or the ova of worms.

=Epithelium in Urine.= The slight cloud seen in healthy urine contains epithelial cells. The source of these may be often determined under the microscope. The bladder epithelium are the most numerous, the largest, and are squamous. Those from the ureters and renal pelvis are also squamous, but neither so large nor so numerous. The epithelium from the uriniferous tubules are polyhedral with large nucleus or columnar. The cells from the male urethra are also largely columnar. In cases, however, in which these cells are passed in large amount because of catarrh of the mucosa all alike tend to assume the globular form with large nucleus so that their true source cannot be certainly stated. It is only from such cells as have become detached without change of form that the seat of desquamation can be determined. If an excess of cells approximating to the kidney type are associated with albuminuria and cylindroid casts they become diagnostically significant. Polygonal cells darkly granular with large oval nucleus and nucleolus suggest kidney inflammation. If the granules are freely soluble in ether there is probably fatty degeneration. If hard, tough and glossy they suggest (but don’t prove) amyloid degeneration.

=Pus Cells in Urine.= Pus cells, with multiple nuclei revealed by adding dilute acetic acid, may be found in small numbers in apparently healthy urine. When present in large numbers, they usually indicate a catarrhal affection of the mucosa, and especially pyelitis, cystitis, or urethritis. There is always cloudiness, excess of mucin, and, in the alkaline herbivorous urine, the liquid may be glairy or stringy.

=Casts of the Uriniferous Tubes.= These usually indicate the existence of nephritis, yet they may be present in small numbers in the urine of healthy individuals under a slight toxic action such as alcohol.

Unorganized casts of urinary salts or hæmatoidin found in sucklings appear to have no pathological significance. Organized casts, on the other hand, usually imply renal troubles, and especially inflammation. As these will be fully described under Bright’s disease, it need only be noted here that they may be composed in great part of red globules, leucocytes, epithelium, bacteria, granules, a homogeneous wax-like matter, fat globules, hyaline matter, or urinary salts. The predominance of one or other of these determines the nature of the cast.

The observations of Mayer, Knoll, Bovida, Von Jaksch and others seem to show that the basis substance of urinary casts differs from all our familiar proteids and must be considered as a distinct nitrogenous compound, a derivative of one of the common proteids.

GENERAL SYMPTOMS OF URINARY DISEASE.

External symptoms, arched back, stiff gait, straining, tender loins, backing, turning, dropping under weight, urine checked, dribbled; in dogs and cats, palpation of kidney; bladder, urethra, pains in different animals. Internal symptoms, rectal exploration, vaginal, urethral, straining, ureters, bladder, calculi, neoplasms, prostate, urethritis.

=External Symptoms.= With inflammatory or painful affections of the urinary organs the animal tends to roach the back or loins, tuck up the abdomen, move the hind limbs stiffly and with a straddling gait, protract and withdraw the penis which may be semi-erect, retract and drop the testicles alternately, and stretch himself and strain to pass urine without success. Lying down and rising may be accomplished with marked effort and groaning. The loins along the spines or beneath the outer ends of the transverse processes may prove tender to tapping or pinching, the animal drooping to excess. Backing or turning in a narrow circle may be accomplished awkwardly and stiffly though usually more easily than with lumbar sprain. The animal drops when mounted but less than with sprained back. Urine may be passed in excess or in diminished amount, or it may be entirely suppressed. It may be abruptly interrupted when in full stream, suggesting calculus or polypus, or it may be passed often in mere dribblets, or finally it may ooze away constantly partly lodging in the sheath and partly trickling down the thighs.

In dogs or cats with flaccid walls of the abdomen external manipulation may detect in the kidneys, differences in size, position, and tenderness as well as the presence of tumors. The distended bladder also may be distinctly felt, and the pyriform area of flatness on percussion will serve to map out its size and outline.

In the horse the urethra is superficial and easily traced over the ischiatic arch and for some distance downward, when it becomes deeper and is less easily felt. In the bull the urethra is deep over the ischiatic arch but becomes more superficial lower down and can be easily felt at the sigmoid flexure and below. In sheep and dog it is easily followed from the ischium to the end of the penis.

As a rule the penis is easily drawn from its sheath in the horse and dog; this is more difficult in the sheep and goat and still more so in the bull and boar. In the small animal protrusion is favored by setting him on his rump, with his back between the operator’s legs, and the pelvis doubled forward toward the sternum. The penis of the bull may be extended in presence of a cow in heat, and promptly seized, or it may be seized through the sheath back of its first bulging part and skillfully worked out. In the ruminant, calculi may be felt at the sigmoid curve, and in the ram, in the vermiform appendix at the fore end of the penis.

=Internal Exploration.= This is accomplished in the larger animals with the oiled hand in the rectum, the nails having been pared short and even to avoid injury to the mucosa. In ponies and yearlings the kidney may be felt, and this may be true also of mature animals of larger species in cases of hypertrophy or floating kidney. The ureters, bladder and intrapelvic urethra are easily felt in the male. The empty bladder lies on the anterior border of the pelvis; when full, it projects forward into the abdomen but retains its pyriform or, in the very young animal, its fusiform shape. In the female the sensation is somewhat modified by the presence on its upper surface of the uterus dividing into its two horns anteriorly. The single enlarged horn of pregnancy is especially misleading.

The female urethra, cervix and bladder may be explored through the vagina. To explore the cervix vesicæ and urethra the fingers are slowly drawn back from the bladder along the median line of the floor of the vagina. In the mare the cervix and adjacent portion of the bladder can be further explored with the index finger introduced through the opening of the urethra in the floor of the pelvis and at the junction of the vagina and vulva. In the cow the urethra is too small to be readily explored from within, and the orifice is still further guarded by the two lateral blind canals of Gærtner, into which the unskilled fingers more readily pass. Success only attends the careful search for the small central lower orifice. In the smaller animals the finger only can be introduced into vagina or rectum and the urethra, cervix and bladder only can be felt. The result of such exploration is straining even in healthy conditions but which becomes excessive in nephritis, pyelitis, renal, urethral, vesical or urethral calculus, cystitis, rectitis or enteritis.

The ureters are tender when inflamed, and they are swollen in calculus obstruction with an elastic feeling in front of the stone.

The bladder is very sensitive when overdistended, inflamed or pendent on the abdominal floor, or when the seat of calculus. In the absence of any liquid contents a calculus is felt as a hard solid mass firmly clasped by the contracted vesical walls. If liquid is present the solid hard calculus is felt movable in the fluid. An empty contracted bladder is firm and pyriform. An empty flaccid bladder, resulting from rupture or exhaustion, is flabby, with indefinite form and, if the seat of a lesion, tender. It varies in consistency with neoplasms (papilloma, sarcoma, carcinoma, or epithelioma). These have not the free mobility of the calculus floating in urine, and their point of connection with the wall may often be made out. When a solid body is felt, or suspected to be in the contracted bladder, an injection of sterilized water will usually facilitate diagnosis, and a differentiation of calculus and neoplasm.

Hypertrophy of the prostate is felt as a swelling of uneven outline over the cervix vesicæ. It is to be looked for especially in old dogs.

Urethritis is indicated by swelling and tenderness along the median line of the pelvic floor, back of the cervix. With a calculus in the urethra the swelling is more strictly localized and the canal in front of it may be full and elastic.

HEMATURIA.