Urolithiasis (stones in the urinary tract) in Dogs


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:

  • Struvite stones: antibiotics to treat bacterial infection
  • Oxalate stones: thiazide diuretics and potassium citrate
  • Urate stones: allopurinol
  • Cystine stones: penicillamine or 2-mercaptopropionyl glycine (2-MPG or Thiola)
  • 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.

  • Clotting disorder (diagnosed with platelet count and tests of blood coagulation)
  • Congenital defects (those present at birth) such as ectopic ureters
  • Bacterial cystitis (lower urinary tract infection)
  • Drug-induced cystitis such as that caused by cyclophosphamide, which is a drug used to treat some types of cancer and immune diseases
  • Hydronephrosis, which is distension of the urinary space within the kidney due to obstruction
  • Cancer of the urinary tract
  • Disorders of the nervous system that interfere with urination
  • Rare parasites of the urinary tract (kidney and bladder worm)
  • Diseases of the prostate gland
  • Vaginal disease
  • 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:

  • A complete medical history. This should be obtained along with a thorough physical examination performed by your veterinarian. Special attention should be paid to palpation of the abdomen (to evaluate for the presence of bladder stones).
  • Urinalysis. This test evaluates for urine pH, urine concentration and the presence of white blood cells, red blood cells, bacteria and crystals. The presence of crystals in the urine does not necessarily imply the presence of urolithiasis. Crystals can be seen in both normal pets and those with urolithiasis. Ideally, urine samples are collected by cystocentesis, which involves placing a needle through the abdominal wall into the bladder. The procedure of cystocentesis avoids genital or urethral contamination of the urine.
  • Bacterial culture of the urine. This test is used to identify urinary tract infection that may occur in pets with urolithiasis. Susceptibility testing of the urine will determine the most effective antibiotic for treatment of the infection.
  • Abdominal X-rays. This test is used to identify uroliths that are dense enough to be observed on plain X-rays. Some calculi cannot be seen on plain X-rays and contrast dye studies may be required.

    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:

  • Complete blood count and serum biochemistry tests to evaluate the general health of your dog, evaluate kidney function, and assure that your dog can be safely anesthetized for surgical procedures to remove stones.
  • Ultrasound examination, which is an imaging technique in which internal organs visualized by means of ultrasonic waves directed into the tissues, and helps to identify obstruction of the urinary tract and stones that may not have been observed on X-ray studies.
  • Contrast dye studies to evaluate for stones not dense enough to be visible on plain X-rays. These studies are called positive contrast studies if contrast dyes are used (dye appears white on X-rays), negative contrast studies if air is used (air appears black on X-rays), and double contrast studies is which both contrast dye and air are used.
  • Urethrocystoscopy during which a rigid or flexible scope is passed into the urethra and bladder for direct visualization of stones or other abnormalities with the possibility of biopsy of the bladder wall.
  • A contrast dye study called intravenous pyelography or excretory urography can be used to evaluate the urinary tract for obstruction or the presence of stones insufficiently dense to be seen on plain X-rays.
  • Analysis of prostate gland fluid to evaluate for prostate infection.
  • Urolith analysis should be performed on retrieved stones to evaluate their mineral composition. This procedure is very important because it helps determine proper treatment and preventative therapy.
  • Liver function tests may be indicated for pets with a specific type of stone (ammonium urate) because these stones often are associated with congenital liver defects (called portosystemic shunts) or other liver disorders.
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