Synonyms:—Stone in the kidney; gravel; renal calculus; renal colic.

Definition:—A condition in which crystalline or other solid or earthy particles are precipitated from the urine and are deposited in the tissues, calyces or pelvis of the kidney.

The precipitation of the inorganic constituents of the urine is of quite common occurrence. When the substance is in fine crystals or finely formed earthy matter, it is called renal sand; when the crystals are large or are coherent, and thus form coarse grains or small concretions, this is designated as gravel. When these concretions increase in size and become too large to pass through the ureter, they form renal calculi, or renal stone.

The most common of the renal concretions are those which consist of uric acid. These occur in size from minute crystals to large stones, are of dark color, very hard, with smooth, uneven surfaces. The next most frequent of occurrence are those of calcium oxalate. These are known as mulberry calculi, and may form around a uric acid nucleus.

Phosphatic calculi are quite common. They are more apt to precipitate in the bladder than in the kidney. They may form in the bladder around a uric acid or oxalic acid nucleus which has escaped from the kidney. The presence of these calculi is a common cause of cystitis. They are by no means as hard as those previously named, are of a yellowish gray or grayish white appearance, and of irregular fracture.

Among other substances which may form renal stone are calcium carbonate, cystin, xanthin and certain saponaceous or fatty substances, classed as urostealith, with fibrin, and in very rare cases, indican. The formation of renal stone depends, first, upon conditions which permit the precipitation of the solids of the urine, and there may be insufficient water, increased solids, or other important changed conditions; and, secondly, upon the presence of some substance which will assist in retaining these particles together, or which will cause them to adhere. At times a calculus may have for its nucleus micro-organisms or an organic substance, or fibrin.

Etiology:—During middle life concretions are less apt to form than in youth and in advanced age. They form more commonly in males than in females, and in certain localities they are much more prevalent than in others. In India, China, in northern Europe, and in some parts of England they are much more prevalent. Those who subsist largely upon a meat diet are more subject to stone, although concretions form readily in the urine of herbiverous animals. That of the former is usually of uric acid; that of the latter is calcic carbonate.

Individuals who live an active life physically in the outdoor air are seldom subject to calculi. The condition appears more commonly among those who are sedentary in their habits and who are large eaters, and those who drink freely of coffee or wines or beer.

Symptomatology:—The conditions which lead us to suspect the presence of gravel are in every way similar to those described in lithuria. The patient is sedentary in his habits, passes a small quantity of dark urine of high specific gravity, and complains of more or less urinary irritation. At the same time there are constant backaches, more or less severe, with occasional shooting pain in the region of the kidney. At other times these conditions are not so marked, and yet a calculus of some size may form in the kidney and remain more or less fixed at some pendent point in the pelvis, when from some severe jar or fall or a severe muscular strain it may be dislodged, and may either lacerate the mucous membrane of the pelvis or occlude the ureter; or it may dislodge small calculi, which, passing into the ureter, will cause immediate occlusion, the pain of which is the first evidence of the presence of a calculus. This may also result in infection of the pelvic membrane and an inflammation which results in pyelitis or in pyelonephritis.

A transient, sharp, cutting pain in the kidney or in the course of the ureter may occur from the passage of grains of sand through the ureter which are not sufficiently large to produce occlusion. These attacks may last for a few moments, or for perhaps half an hour, without the extreme pain of a large calculus. The abrupt and complete relief from the pain proves that the obstruction has passed into the bladder. These attacks may occur at intervals for quite a period of time before a calculus sufficiently large to distend the ureter or to completely obstruct the passage is deposited. With elderly patients this condition may last for a number of years, both the patient and the physician being conscious that he has gravel, and that he is liable to have an attack of renal colic. He is of feeble health usually or disabled for active labor, has backache or constant pain and hematuria or pyuria. At times, if a small calculus is smooth and does not cause a great degree of irritation, there may be only an obstruction to the flow of the urine and but little pain as an evidence of its presence.

The larger stones produce agonizing pain, which usually, occurs abruptly, is located in the kidney, and passes down the course of the ureter on the affected side to the inner side of the thigh, and into the testicle in the male, which, because of reflex irritation in the cremaster muscle, will retract and become very tender and sensitive. This pain is almost continuous during the passage of the stone. It is often tearing or lacerating in character, and will produce intense agony, causing vomiting, extreme perspiration and nervous shock. It may radiate up into the chest and produce some dyspnea, or may seem to extend into the muscles of the back. This pain may last from half an hour to several hours. Usually there will be an occasional remission in the extreme agony, or there may be a temporary suspension of the sharp pain, but this period of relief is of short duration until the stone has escaped into the bladder.

Usually this pain is accompanied with a constant desire to urinate, with much irritation and tenesmus. The urine is of high specific gravity and contains much blood. However, it is often the case that the normal kidney excretes more freely and the urine and blood are not will mixed.

Occasionally the extreme pain and nervous irritation induce convulsions. While the skin is cool or cold, the temperature often rises from one to four degrees above normal. The pulse is small, hard and sharp, and in the older patients may be irregular. For days after recovery from the attack the patient is prostrated, has but little appetite, and there is much soreness in the kidney, ureter or in the testicle.

If a calculus is lodged in the ureter and is too large to pass through, permanent occlusion results. The pain will be described as most excruciating for some hours, and as the spasm of the muscular coat of the ureter abates the pain may cease, to an extent at first, and ultimately disappear. The urine accumulates in the pelvis of the kidney and soon blocks up the flow of urine through the tubes, and suspends renal action because the pressure of the urine in the pelvis exceeds that in the renal arteries. As the pelvis becomes distended, the condition known as hydronephrosis is produced, with the symptoms described under that title. Compensatory activity of the normal kidney may be sufficient, and no uremic symptoms may appear. It is seldom, however, that there is not a deficiency of urine, with more or less uremia. In rare cases both ureters may be occluded, when permanent suppression of urine, uremic intoxication and death may occur.

The continued presence of an irritating calculus or calculi in the pelvis of the kidney develops irritative inflammation and pyelitis, with the phenomena described under that head. This may result in the absorption of septic material; the patient may have hectic fever, with night sweats, or there may be urinary suppression from sepsis. In cases where this condition persists, chronic disease of the liver and spleen is apt to occur.

Diagnosis:—The disorder must be distinguished from hepatic colic, from neuralgia, and from the pain of appendicitis; in the female, from ovarian neuralgia and the pain of dysmenorrhea. This is usually accomplished without difficulty by the character of the urine and the urination. In extreme cases, in the male, the pain in the testicle and in the inside of the thigh is an important diagnostic factor. The sudden occurrence and sudden disappearance of the pain are characteristic phenomena. Usually the diagnosis can be confirmed without doubt by the discovery of gravel in the urine. The Roentgen ray may assist in confirming the presence of renal calculi, but this is often misleading and has led to confusion.

Prognosis:—The prognosis is favorable in all cases except where the ureter is permanently occluded. The constitutional condition which permits the formation of calculi is amenable to treatment if perfect co-operation of the patient is secured. If pyelitis or hydronephrosis occur, the prognosis is unfavorable.

Treatment:—No physician should permit a case of simple gravel to continue from year to year, until occlusion of the ureter occurs, without making every effort to change all the conditions which conduce to the formation of gravel, to encourage the excretion of renal sand, and to relieve irritability of the renal pelvis. This is accomplished by a change in the habits of life of the patient. He should be forced to subsist exclusively upon a vegetable diet for a period of time, the character of which is decided by the physician from the results of the treatment. He should eat sparingly of all foods, should arbitrarily exclude wine, beer and other alcoholics, and tobacco and coffee, and should drink freely of pure, fresh water, or a carefully selected mineral water which contains calcium carbonate. It is the theory of certain foreign writers that the calcium in the system is readily freed from its union with the carbonyl radical, and in a nascent state unites with the acid phosphate, reducing the deuterophosphates, when the uric acid is readily dissolved by the protophosphates, which remain.

Medicinal agents which promote this result are small doses of acetate of potassium, with triticum or epigea, in the form of infusion. It is well to give the patient from four to eight ounces of an infusion of one of these last named substances regularly, at stated intervals, to which may be added a grain or two of the potassium acetate and two or three minims of gelsemium.

This may be alternated with an infusion of marshmallows when the backache increases, or with eryngium, to which a few drops of macrotys are added. I believe the salts of lithia are mildly effective in promoting this result. I prefer the benzoate usually, although the carbonate will be found of much efficacy in some cases. For twelve or fourteen years I have been in the habit of prescribing piperazin to overcome the uric acid tendency, and have found it a valuable remedy. I have given it in from four to eight grain doses every four hours, in a glass of cold water.

An attack of renal colic must have prompt and immediate treatment. Temporizing measures should be avoided. Hot baths and hot applications, with a full, large dose of from five to ten drops of gelsemium to relieve spasm of the ureter, will be found of service, but usually it will be necessary to administer a hypodermic of morphin. Occasionally it will be necessary, the condition of the heart permitting, to anesthetize the patient with chloroform or ether. When relief from the pain is obtained, a course should be laid out for the patient similar to that just above described, to overcome the tendency to the formation of calculi, to prevent their future formation, and to rid the system of accumulated sand. I have observed where such a course was instituted abruptly that the washing out of the renal pelvis has resulted in the occurrence at short intervals of quite a number of attacks of renal colic, more or less severe in character, until the earthy sediment was no longer found in the urine, when complete relief was obtained.

Where the severe pain has produced shock or other constitutional symptoms, these must be overcome by the prompt use of stimulants or tonic remedies. An experienced physician, after having watched a patient, will soon be enabled to determine the presence of a stone in the kidney too large to pass the urethra, when no time should be lost, the conditions being favorable, in resorting to a surgical operation for its removal.

The Eclectic Practice of Medicine with especial reference to the Treatment of Disease, 1910, was written by Finley Ellingwood, M.D.