CALCULUS, or STONE (in medicine), a hard concretion formed within the animal body, in consequence of the deposition h the solid form of matters which usually remain in solution. See CONCRETION. The concretions most commonly termed caleult are those formed in the kidneys or bladder (urinary C.); and those formed in the gall bladder or biliary ducts (biliary C.). Both of these give rise to very painful symptoms, and may even threaten life.
Biliary a, or may generally be presumed to exist when excessively severe pain suddenly arises in the right side beneath the border of the ribs, and when in a few hours jaundice comes on, showing that some obstruction has existed to the outward flow of the bile. But the absolute proof that these symptoms depend on C. is often wanting The pain is fortunately transitory, but is more severe while it lasts than ahnost any other known form of suffering, unless it be that of a C. in the kidney and ureter. It may be relieved by large doses of opium, but the remedy requires to be cau tiously given, as evert in medical hands fatal accidents have occurred. Gall-stones, when impacted in the ducts, sometimes have proved fatal; but much more frequently they find their way, sooner or later, into the intestines. They are almost invariably composed of cholesterin (q.v.), with coloriug matter and mucus, arranged in layers in a semi-crystalline disposition.
C. is a disease of all agtV, but most common in advanced life and in the inale sex. It is also very frequent in o.
gouty persons, or among is those who pursue seden tary occupations and live freely. It s rare among those much in the open air, or who take much violent exercise, and use little animal food and wine. Among sail ors, it is peculiarly rare. In certain parts of the country, the disease is said to be fre quent, as in Norfolk, and perhaps along the e. coast of Scotland. In India, too, where some of the predisposing circumstances mentioned above can hardly be said to prevail, stone is by no means uncommon. It would appear, therefore, that the predisposing causes of C. are still very imperfectly understood. In its early stages, the disease usu ally presents itself in the form of gravel, shown by the passage of numerous very small portions of gritty concretions, which may be observed in the urine as a deposit like sand, or like small grains of Cayenne pepper. When such deposits occur frequently, especially if they are present at the time of passing the urine, and not merely after it has cooled, there is reason to apprehend the formation of calculus. If, in these circum stances, there are pains of a dull character in the loins, with occasional twinges of sharper suffering, no time should be lost in seeking medical advice. If a fit of very severe pain should occur in a person for some time affected with gravel, if the urine be bloody, if agonizing twinges, commencing in the loins, sting downwards into the thigh or the groin, it is probable that a stone has already formed in the kidney, and is being displaced towards the bladder. C. in the bladder is at first attended with little suffer•
ing, as compared with that caused by the stone in its passage downwards from the kidney; but unless removed or evacuated, the C. is sure to enlarge, and it then becomes the cause of one of the most painful diseases that afflict humanity. The existence of a stone in the bladder, however, should never be taken for granted without a surgical examination, as all the symptoms are deceptive in certain cases. The most striking, and perhaps the most trustworthy- evidence of stone in the bladder, apart from the use of,the sound (see LiTnoTomv), is smarting and burning pain experienced after the blad der has been emptied, together with occasional temporary stoppage in the flow of urine.
The correct appreciation of all the symptoms, however, demands considerable famil iarity with such cases.
The discovery of the tendency to urinary C. at an early period of its growth, has been greatly aided by the use of the microscope and of chemical tests. Generally speak ing, it may be said that whenever the urine, after standing for a few hours, can be observed to contain more sediment than a very slight cloudiness towards the bottom of the vessel, there is room for careful inquiry into the existence of some derangement of the health. But all sediments are not equally apt to determine C., nor is the treatment of the different kinds of sediment at all similar; care should therefore be taken to deter mine, from time to time, whether the character of the sediment may have undergone a change, so that the treatment may be adapted accordingly.
The chief varieties of urinary C. are-1. Uric acid (red sand); 2. Urates of ammonia, soda, lime, etc. (brick-dust sediment); 3. Phosphates of ammonia and magnesia. lime, etc.; 4. Oxalate of lime; 5. Carbonate of lime (chiefly in domestic animals); 6. Cystine; 7. Xanthic oxide (a very rare form, discovered by Dr. Marcet). Calculi are frequently found to be composed of numerous successive layers, having a perfectly distinct chemical composition. Urates and phosphates in particular frequently succeed each other, and form what is called an alternating calculus.
When C. has once fairly formed in the urinary passages, it seems probable that no absolute cure exists except the removal of it, if possible, from the body (see LITROTOMY and LITHOTRITY); but in the stage of gravel, and still more in the earlier stages detected by careful examination of the urine, much may be done to check the tendency to this distressing and dangerous malady. The chief remedies consist in careful regulation of the diet and mode of living, together with the use of solvents adapted to the particular form of deposit found to be habitually present. See URINE.