Stones are sometimes found in the kidney. They are composed chiefly of uric acid in combination with ammonia, and of phosphate of lime. Calculi composed of oxalic acid and of cystine are more rare.

A nucleus having once formed, the stone gradually increases in size by further additions to its substance. The irritation produced in the kidney aids in its enlargement, by changing the character of the natural secretion. The stone varies in shape according to the particular part of the kidney in which it is lodged. Inflammation and suppuration may be the consequences of the stone acquiring considerable size and remaining in the kidney.

Symptoms

The symptoms are somewhat obscure. Vomiting or retching, occasional admixture of blood in the urine, especially after exercise; frequent passage of urine and colicky attacks are the most marked. Eventually the animal becomes emaciated, and dies exhausted from the severe pain and discharge of blood and mucus. He is frequently, however, carried off by nephritis.

In many cases, the stone when small descends from the kidney into the bladder along the ureter; this passage may be effected without exciting any symptoms, especially if the stone be smooth and of little size. But, in other cases, considerable pain is caused, and the dog suffers from all the symptoms of colic, added to those which betoken disturbance of the bladder.

M. Lautour records a typical case, which will serve to illustrate these remarks. A dog that had previously had occasional attacks of pain, attended with difficulty in voiding the urine, was suddenly seized, on August 20, 1827, with violent pain. "He barked and rolled himself on the ground almost every minute; he made frequent attempts to void his urine, which came from him drop by drop. When compelled to walk, his hind and fore legs seemed to mingle together, and his loins were bent with a perfect curve; his flanks were drawn in; he could scarcely be induced to eat; and he evidently suffered much in voiding his faeces. Mild and demulcent liquids were his only food. Warm baths and injections were applied almost unceasingly, and in eight days he seemed to have perfectly gained his health. In March of the following year the symptoms returned with greater intensity. His hind-legs were drawn after him, he rapidly lost flesh, and his howlings were fearful and continuous. The same mode of treatment was adopted without any good effect." A calculus, weighing 126 grains, and composed of urate of ammonia and phosphate and oxalate of lime, was found in the pelvis of the kidney. The kidney itself was increased in size fourfold, the mucous membrane covered with ecchymoses, and the walls of the bladder thickened.

Treatment

The symptoms produced by the presence of a stone in the bladder or in the ureter can be best combated by Belladonna, Cannabis, and Cantharis.

Belladonna* is indicated for great pain, the existence of which may be inferred from the dog's behaviour.

Cannabis may be substituted for the last medicine when it appears to relieve the pain only partially.

Cantharis is efficacious when the urine is bloody and discharged with difficulty drop by drop.

Food, Etc

Demulcents and plenty of water forced upon the dog soothe the parts which are irritated by the stone, and assist in dislodging it.

* For the dose, etc., see "Introductory Remarks."