Urolithiasis (stones in the urinary tract) in Dogs

Overview of Urolithiasis (Stones in the Urinary Tract) in Dogs

Urolithiasis refers to the formation of stones (calculi or uroliths) in the urinary tract. Calculi can be found anywhere in the urinary tract, in the kidneys, the ureter or the bladder, but are most common in the bladder.

Calculi form due to oversaturation of the urine with certain minerals. Several factors may contribute to this oversaturation including increased concentrations of specific minerals in the urine, alterations in the pH (acidity or alkalinity), highly concentrated urine, presence or absence of stimulators, and inhibitors of crystal formation.

Several factors can contribute to development of urolithiasis. These include:

The various types of calculi are named according their predominant mineral composition. In dogs, calculi composed of the minerals magnesium ammonium phosphate (commonly called struvite) and calcium oxalate are most common. Urate calculi occur less commonly, often in Dalmatians or English bulldogs. Cystine and silica calculi are relatively rare. The different types of calculi must be treated differently. Consequently, it is important for your veterinarian to be able to obtain calculi for chemical analysis.

Certain breeds of dogs are genetically predisposed to specific stone types. These include:

The risk of recurrence for urolithiasis is high and ranges from 20 to 50 percent. The pet’s symptoms depend upon the number of stones, their location in the urinary tract, the physical characteristics of the stones (smooth or jagged), and the presence of bacterial urinary tract infection.

What to Watch For

Signs of stones in the urinary tract in dogs may include:

Symptoms caused by kidney stones include back or abdominal pain or occasionally abnormal odor to the urine if bacterial infection is present. Surprisingly, however, many pets with kidney stones have few or no symptoms.

Diagnosis of Urolithiasis in Dogs

Diagnostic tests are needed to identify urolithiasis as the cause of your pet’s symptoms and to exclude other disease processes. Your veterinarian may recommend:

Other diagnostic tests that may be completed include:

Treatment of Urolithiasis in Dogs

Treatments for urolithiasis may include one or more of the following:

Home Care

At home, be sure to administer any medications prescribed by your veterinarian. Give antibiotics according to the schedule prescribed. It’s important to allow your pet free access to fresh clean water.

Follow-up with your veterinarian for physical examinations and urinalysis as directed. Urine culture should be repeated 5 to 7 days after completion of antibiotic treatment to ensure eradication of infection. If your pet has a poor response to treatment, further workup may be required to search for underlying disease processes.

Stone analysis will guide your veterinarian’s treatment plan:

Preventative Care

Most stones are difficult to prevent. Providing your dog with frequent opportunities to urinate and an ample supply of fresh clean water may help.

Prompt treatment of urinary tract infections can help reduce the potential for certain stone formation.

In-depth Information on Urolithiasis in Dogs

Other medical problems can cause symptoms similar to those encountered in dogs with urolithiasis. Your veterinarian will exclude these conditions as necessary before establishing a diagnosis of urolithiasis.

Veterinary care should include diagnostic tests and subsequent treatment recommendations.

In-depth Information on Diagnosis

Certain diagnostic tests must be performed to confirm the diagnosis of urolithiasis and exclude other diseases that may cause similar symptoms. Tests may include:

Your veterinarian may recommend additional diagnostic tests to exclude other conditions, and to better understand the impact of urolithiasis on your pet. These tests ensure optimal medical care and are selected on a case-by-case basis. Examples include:

In-depth Information on Treatment

Treatment of urolithiasis must be individualized based on the severity of the condition and other factors that must be evaluated by your veterinarian. Treatment may include one or more of the following:

Ideally, a stone is obtained for analysis to determine its mineral composition and to decide between medical and surgical therapy. Only some stone types can be treated (dissolved) by medical means. Stones that have been passed in the urine can be submitted for analysis or small stones can be obtained by a technique called urohydropropulsion that is performed under general anesthesia. Small stones can be retrieved from the bladder using a technique called catheter-assisted urolith retrieval, which can be performed under sedation.

Dissolution of stones can take several months. Medical dissolution carries with it the risk of urinary obstruction because bladder stones may become small enough to lodge in the urethra as they dissolve and kidney stones can become small enough to lodge in the ureters as they dissolve. Your veterinarian may recommend adding salt to your pet’s diet to increase urine production and decrease the concentration of the urine. This approach typically is used for pets with struvite and urate stones but not for those with oxalate or cystine stones. Medical dissolution of stones is not recommenced for patients with heart disease, hypertension, kidney failure or those at risk for obstruction.

Follow-up care for Dogs with Urolithiasis

Optimal treatment for your dog requires a combination of home and professional veterinary care. Follow-up with your veterinarian is essential. Administer any antibiotics prescribed by your veterinarian and allow your pet free access to fresh clean water.

If your dog has had surgical removal of calculi, monitor the incision site for redness, swelling or discharge. Do not allow your pet to lick at the suture area. An Elizabethan collar can be used for pets that tend to lick their incisions. Call your veterinarian if you have questions or problems.

Follow-up with your veterinarian for physical examinations and urinalysis. Bacterial culture of the urine should be repeated 5 to 7 days after completion of the antibiotic course to ensue eradication of infection. Periodic urinalyses are recommended every several months to monitor for development of new bacterial urinary tract infections.