Bobo is a 7 year old, 24 lb., female, spayed, Poodle/Bichon mix. She presents to us for the first time for a routine annual wellness exam and vaccines. She has seemed generally healthy recently. She is reported to have urination accidents in the house occasionally and to have had recurrent urinary tract infections. On physical exam she is mildly overweight with moderate tartar and what appears to be a broken tooth. The abdomen seems generally comfortable during palpation but a firm, gritty mass is found in the caudal abdomen. She does not appreciate the mass palpated.
What are your next diagnostic steps and what are you going to do about what you find?
The first diagnostic test should be an X-ray to try to determine the nature of the mass. The X-rays show the skeletal structures and most of the abdomen to be normal. The urinary bladder is moderately large for a dog of this size. It is filled with radiopaque material consistent with a very large number of bladder stones.
At this point we do not know what type of stones are present. However, she is symptomatic so surgery is recommended to remove the stones from the urinary bladder. Urinalysis and blood work are performed for diagnostic purposes and to look for problems that will influence anesthesia. The blood work is normal. The urinalysis shows a bacterial urinary tract infection.
It is quite common for dogs and cats with bladder stones to have ongoing and difficult to treat urinary tract infections. The bacteria set up house inside the stones and the antibiotics have a difficult time penetrating to kill them. This is why we recommend a patient with recurrent UTI to get an X ray and/or ultrasound of the bladder. Not all stones show up on the X-rays.
Bobo was treated with antibiotics for about a week prior to surgery to decreased the likelihood of infection spreading to the abdomen during surgery. She then had a cystotomy (bladder surgery) performed to remove the stones. Usually we only find 1 to a few stones in the bladder. We were expecting a lot of stones and Bobo did not disappoint.
Bobo had a routine recovery and her owners report her to be doing better now than before surgery. She is more active and seems happier. The stones were sent to a lab to find out what kind they are. Analysis showed them to be struvite. This is the most common type of stone we find in cats and dogs.
The long term management of struvite bladder stones is through control of the diet. We choose a prescription food that is low in the precursors for forming the stones, dilutes the urine somewhat, and changes the pH to a target range for the different types of stones. The goal is to prevent more stones from forming. There are no over the counter foods that meet the nutritional needs of a dog or cat with this problem.