Factors for the formation of urinary stones: the salt content in the urine is high enough, the urine has enough time in the urinary tract, the appropriate pH, the core or mother core of crystal formation and supersaturated urine. In some cases, supersaturated urine may also develop due to reduced tubular reabsorption or increased urinary content of metabolites of bacterial infection.

Stone formation theory: 1. Precipitation-crystallization theory. Supersaturated urine is the main reason for the formation of mother nuclei and the growth of stones. The higher the concentration of supersaturated urine, the higher the probability of crystallization. 2. Mother core theory. Some organic matter in urine will promote the formation of early mother nuclei of stones.

Stone classification

● Magnesium ammonium phosphate stones

Magnesium ammonium phosphate stones, also known as struvite, are the most common stones in dogs. Urinary tract infection in dogs is an important condition for the formation of struvite stones, as is the alkalinization of the urine. Most struvite stones in cats form in the context of non-urinary tract infections. The higher the supersaturation of the urine, the more likely it is to occur.

　●Calcium oxalate stones

Calcium oxalate stones include excessive calcium ion concentration in urine, excessive urinary oxalic acid, and excessive uric acid.

When the pH of urine is above 6.5, the solubility of calcium oxalate will increase, and when the pH of urine is below 6.5, calcium oxalate will precipitate.

​● Urate stones

Most urate stones are ammonium urate. Dalmatians and some English Bulldogs have a defect in the ability of the liver to transfer uric acid, resulting in reduced urea production resulting in increased levels of uric acid in the urine. Therefore, the incidence rate is very high. Urinary tract infections, especially those caused by urease-producing bacteria, increase the amount of ammonia in the urine, promoting the formation of ammonium urate stones. Acidic urine favors the formation of urate crystals, while alkaline urine favors the formation of ammonium urate crystals.

　●Silicate stones

Silicate stones are often polygonal, and polygonal stones are all silicate stones. Wheat bran and soybean hulls contain high levels of silicates, which can predispose you to the disease. Alkaline urine can promote the dissolution of silicate, and silicate stones can irritate the urethral mucosa and cause urinary tract infection.

​● Cystine stones

The main cause of cystine stone formation is cystinuria caused by hereditary renal tubular transport dysfunction. Cystine stones appear in acidified urine.

Nephroliths

The presence of stones in the kidneys. The incidence rate in dogs is only 5 to 10%. The incidence is lower in cats.

【Cause】

1. In nephritis, struvite nephrolithiasis is prone to occur.

2.Dogs with acid reabsorption defects are susceptible to cystine nephrolithiasis.

3. Generally it will not affect kidney function but may become a site for bacterial infection.

【Clinical symptoms】

Most have no clinical symptoms. hematuria. Painful urination. Abdominal pain in kidney area. Kidney enlargement. Bun, cre levels are elevated. Urinary tract infection, etc.

【Diagnosis】

1. Radiography or/and ultrasound examination 2. Evaluation of renal function and stone structure.

【Treatment】

A. Nephrotomy, pyelotomy or nephrolithotomy can be performed.

B. Surgery can seriously affect the function of the operated kidney in the short term (and may also have long-term effects).

C. For bilateral nephrolithiasis, they can be surgically removed 2-4 weeks apart.

D. Qualitative analysis should be performed on the removed stones.

Medical treatment: A. For those dogs prone to urinary tract infections and suspected mineral kidney stones, medical treatment is the best choice. (See below)

Calcium oxalate nephrolithiasis cannot be dissolved by medical treatment.

Ureteral obstruction

Ureteral stones form in the kidneys, enter the ureters, and stay temporarily or permanently.

【Cause】

Ureteral stones come from the kidneys.

【Clinical symptoms】

The clinical symptoms of ureteral stone obstruction are affected by the acuteness, completeness, duration and whether it is one or both sides of the ureteral obstruction.

1. Abdominal pain and/or low back pain, hematuria, vomiting, restlessness, depression, abdominal wall tension, sensitivity to palpation, and enlarged kidneys (hydronephrosis).

2. Obstruction on both sides or one side is accompanied by decreased renal function on the contralateral side, accompanied by uremia.

3. If the ureteral stones are successfully discharged to the bladder, the symptoms are transient.

4. Some ureteral stones have no symptoms.

【Diagnosis】

Radiology and Ultrasound Diagnosis

Descending urography. Contrast medium can stay in the kidneys for an extended period of time or accumulate in obstructions.

【Treatment】

A. Prevent urinary tract obstruction.

B. Protect kidney function.

C. Control urinary tract infection.

D. Control clinical symptoms.

e. If kidney function still exists, ureteral stones should be removed surgically if possible.

f. If one side of the kidney is severely damaged and the contralateral kidney has normal function, unilateral nephroureterectomy can be performed.