If after careful watching no stone makes its appearance, and on the other hand the pain does not continue and no pus gives evidence of pyelitis, it is highly probable that no stone is or has been present.
A true neuralgia of the kidney may undoubtedly exist. Lumbago and lumbar neuralgia may simulate renal colic, but are almost always much less severe, the pain less sharp and more dull and aching, aggravated by movement, while the sympathetic phenomena, especially those connected with the urinary apparatus, are wanting.
The diagnosis of the character of the calculus can sometimes be made with a reasonable degree of probability. If crystals of uric acid or of oxalate of lime have been or are present in considerable quantity, it is highly probable that a possible stone may consist of those substances. These crystals, however, are of little value in proving the presence of a stone.
The important diagnosis of the occlusion of a ureter by a calculus, and at the same time that of the soundness of the opposite kidney, may be made with great certainty if the urine, which has previously been purulent, bloody, or containing renal epithelium or casts, suddenly becomes clear coincidently with the occurrence of symptoms of the impaction of a stone.
It is not of course necessary that in every case of impaction the flow of urine from the affected side should be entirely stopped, since the calculus may be of such a shape as to permit the passage of urine past it.
The PROGNOSIS in this affection is extremely favorable, so far as the recovery from the individual attack is concerned, since if the stone is small enough to enter the ureter it will probably be successful in forcing its way through sooner or later. It is of course possible that this pain, like any other of excessive severity, might cause death, but such an occurrence must be extremely rare.
Perforation of the ureter may occur, with consequent peritonitis. A permanent plugging of the ureter from failure of the calculus to pass will give rise to changes in the kidney to be subsequently described.
In cases where only a single kidney exists, and this becomes obstructed, the symptoms of suppression of the urine may come on, including death by coma if the obstruction is not relieved. Ten days is the limit assigned by Ebstein beyond which recovery is not to be expected, but he mentions a case in which it took place after thirteen days of anuria. It must be remembered that a painful obstruction, or in fact any severe shock to one kidney, may produce a very great diminution in the amount of urine even when the other is sound. This is undoubtedly the result of nervous sympathy.
One attack of renal colic renders another very probable, either immediately or after months or years. Several hundred small calculi may follow each other in rapid succession, or, on the other hand, a single one may leave the patient in peace for a long time. Much depends on the character of the calculus, the diathesis and habits of the patient, and upon the treatment.
The subsequent history of the renal calculus belongs to surgery. After it has reached the bladder and failed to be discharged, it increases in size and is removed by lithotomy or lithotrity. The urethra, however, will usually permit to pass any stone which has come through the ureter. The patient who has just experienced relief from renal colic should be instructed to pass his water into a vessel which can be examined, and if the calculus do not soon make its appearance he should void the urine when stooping forward or even lying on his face, so as to bring the stone to the orifice of the urethra. It may catch in the urethra and demand surgical interference.