URETERAL CALCULI.
These are small stones which have passed from the pelvis of the kidney into the canal (ureter) leading from the kidney to the bladder, but, being too large to pass on easily, have blocked that canal and forced the urine back upon the kidney. The result is the production of symptoms more violent than in renal calculi, though not varying, save in intensity, from those of renal colic. In case of complete and unrelieved obstruction, the secretion of the kidney on that side is entirely abolished, and it becomes the seat of passive congestion, and it may even be absorbed in greater part or as a whole, leaving only a fibrous sac containing fluid with a urinous odor. In small cattle, in which the oiled hand introduced into the last gut may reach the affected part, the distended ureter may be felt as a tense, elastic cord, extending forward from the point of obstruction on the lateral wall of the pelvis and beneath the loins toward the kidney. If relief is obtained by the onward passage of the stone a free flow of urine usually follows, in the midst of which may often be found gritty masses. If the outlets from both kidneys are similarly blocked the animal becomes poisoned by the retention in the blood of the elements of the urine, and by their reabsorption after secretion.
Treatment of renal and ureteral calculi.—Treatment is not very successful, as only the smallest calculi can pass through the ureter and enter the bladder, and even if they should do so they are liable to a progressive increase there, so that later they may cause the symptoms of stone in the bladder. Fortunately, ordinary dairy, growing, or fattening cattle rarely show evident symptoms of illness, and even though they do so they can usually be fattened and slaughtered before the health is seriously impaired. In work oxen the case is different, and acute symptoms may develop, but even then the animal may often be fitted for the butcher. When treatment is demanded it is primarily soothing and antispasmodic. Fomentations with warm water over the loins should be persisted in without intermission until relief has been secured. The soothing effect on the kidney will often relieve inflammation and irritation, should the stone be in that situation, while if in the ureter the warm fomentations will at once soothe irritation, relax spasm of the muscular coat of the canal, and favor an abundant secretion from the kidney, which, pressing on the obstructing stone, may slowly push it on into the bladder. Large doses of laudanum (2 ounces) or of solid extract of belladonna (2 drams) will not only soothe the pain but relax the spasm and favor the onward passage of the calculus. The animal should be encouraged to drink large quantities of cool water to favor the free secretion of a very watery urine, which will not only serve to obviate irritation and continued deposit caused by a highly concentrated urine, but will press the stone onward toward the bladder, and even in certain cases will tend to disintegrate it by solution of some of its elements, and thus to favor its crumbling and expulsion. This is a principle which must never be lost sight of in the treatment of calculi. The immersion of the stone in a liquid of a lower specific gravity than that in which it has formed and grown tends to dissolve out the more soluble of its component parts, and thus to destroy its density and cohesion at all points, and thereby to favor its complete disintegration and expulsion. This explains why cattle taken from a herd on magnesian limestone in spring, after the long, dry feeding of winter, usually have renal calculi, while cattle from the same herd in the fall, after a summer's run on a succulent pasture, are almost always free from concretions. The abundance of liquid taken in the green feed and expelled through the kidneys and the low density or watery nature of the urine have so opened the texture and destroyed the density of the smaller stones and gravel that they have all been disintegrated and removed. This, too, is the main reason why benefit is derived from a prolonged stay at mineral springs by the human victims of gravel. If they had swallowed the same number of quarts of pure water at home and distributed it at suitable times each day, they would have benefited largely without a visit to the springs.
It follows from what has been just said that a succulent diet, including a large quantity of water (gruels, sloppy mashes, turnips, beets, potatoes, apples, pumpkins, ensilage, succulent grasses), is an important factor in the relief of the milder forms of stone and gravel.
Prevention.—Prevention of calculus especially demands this supply of water and watery rations on all soils and in all conditions in which there is a predisposition to the disease. It must also be sought by attempts to obviate all those conditions mentioned above as causative of the malady. Sometimes good rain water can be furnished in limestone districts, but putrid or bad-smelling rain water is to be avoided as probably more injurious than that from the limestone. Unsuccessful attempts have been made to dissolve calculi by alkaline salts and mineral acids, respectively, but their failure as a remedy does not necessarily condemn them as preventives. One dram of caustic potash or of hydrochloric acid may be given daily in the drinking water. In diametrically opposite ways these attack and decompose the less soluble salts and form new ones which are more soluble and therefore little disposed to precipitate in the solid form. Both are beneficial as increasing the secretion of urine. In cases in which the diet has been too highly charged with phosphates (wheat bran, etc.), these aliments must be restricted and water allowed ad libitum. If the crystals passed with the urine are the sharp angular (octahedral) ones of oxalate of lime, then the breathing should be made more active by exercise, and any disease of the lungs subjected to appropriate treatment. If the crystals are triangular prisms of ammonia-magnesium phosphate or starlike forms with feathery rays, the indications are to withhold the feed or water that abounds in magnesia and check the fermentation in the urine by attempts to destroy its bacteria. In the latter direction plenty of pure-water diuretics, and a daily dose of oil of turpentine in milk, or a dose thrice a day of a solution containing one-tenth grain each of biniodid of mercury and iodid of potassium would be indicated.
In considering the subject of prevention, it must never be forgotten that any disease of a distant organ which determines the passage from the blood into the urine of albumin or any other colloid (uncrystallizable) body is strongly provocative of calculus, and should, if possible, be corrected. Apart from cases from geological formation, faulty feeding, and other causes, the grand preventive of calculus is a long, summer's pasturage of succulent grasses, or in winter a diet of ensilage or other succulent feed.
The calculi formed in part of silica demand special notice. This agent is secreted in the urine in the form of silicate of potash and is thrown down as insoluble silica when a stronger acid displaces it by combining with the potash to its exclusion. In cases of siliceous calculi, accordingly, the appropriate chemical prevention is caustic potash, which being present in the free state would attract to itself any free acid and leave the silica in its soluble condition as silicate of potash.
STONE IN THE BLADDER (VESICAL CALCULUS, OR URETHRAL CALCULUS).
Stone in the bladder may be of any size, but in the ox does not usually exceed half an inch in diameter. There may, however, be a number of small calculi; indeed, they are sometimes so small and numerous as to form a small, pulpy magma by which the bladder is considerably distended.
Symptoms.—The symptoms of stone in the bladder may be absent until one of the masses escapes into the urethra, but when this occurs the escape of urine is prevented, or it is allowed to pass in drops or driblets only, and the effect of such obstruction becomes manifest. The point of obstruction is not always the same, but it is most frequently at the S-shaped curve of the penis, just above the testicles or scrotum. In cows and heifers the urethra is so short and becomes so widely dilated during the urination that the calculi easily escape in the flow of liquid and dangerous symptoms practically never appear.