All dogs, purebred and mixed-breed alike, can get bladder stones. There are several different types of stones, and they all have different causes. Some stones are more common than others. Deerhounds as a rule have a low reported incidence of bladder stones, except for one: INTACT MALE DEERHOUNDS can get cystine stones. Cystine stones are rare in the dog population as a whole—so rare, many vets can go through their whole careers and never see a case—but have been seen in many breeds and mixed breeds. Cystine stones are by far the most common stones found in Deerhounds, even though they are only found in intact males.
In humans, cystinuria, the disease that causes cystine stones to form, is usually genetic, and that appears to also be the case with many dogs. Here is an article that explains cystinuria in dogs.
In decades of following cystinuria in Deerhounds, it is clear that Deerhounds have Type III cystinuria, the type that only affects intact male dogs. A paper is currently being written that will provide the data to support that.
In Deerhounds, problems usually develop in dogs in ages 4–8, although dogs have formed stones as young as 2 years and as old as 10 years.
Monitor Your Intact Males
Owners of intact male dogs should watch their dog urinate every day so they can learn what their dog’s normal urine stream looks like and can detect any problems early. If there is any change in your dog’s urine stream or color or you see blood in your dog’s urine, make an appointment with your veterinarian as soon as possible and watch your dog urinate every time he goes out to make sure he doesn’t block in the meantime. If your dog strains to urinate and/or nothing or only a few drops come out,
THIS IS A LIFE-THREATENING EMERGENCY, AND YOU SHOULD SEEK TREATMENT IMMEDIATELY.
If a problem occurs, if cystine crystals are not present in the urine, diagnosis is usually made using x-rays or ultrasound. However, there have been cases of cystine stones that were not detectable on x-ray or ultrasound. Stone size can range from sludge or sediment to sizeable stones. Small stones can go down the urethra, which can complicate stone removal surgery.
Here is more information on bladder stones in Deerhounds.
Other things you can do to monitor for cystinuria is to regularly bring in urine samples to your veterinarian to check for cystine crystals, which can be seen on a regular urinalysis, or send urine samples to either PennGen or UC Davis for a cystine/creatinine ratio test. (The Nitroprusside test run by the University of Pennsylvania mentioned in the article above has been replaced with the more accurate COLA quantitative test.) However, these tests are “moments in time” tests, and no one knows how quickly stones form in dogs that test positive, so a negative test cannot predict what will happen in the future.
Preventing Cystine Stones
Cystinuria can be prevented simply by neutering your dog, and if your dog develops cystine stones, neutering alone will prevent a recurrence. Chemical castration appears to work as well as surgical castration, although we don’t have as much data on that, as chemical castration is not used in the U.S. Special diets or supplements are not generally needed in neutered dogs and will not prevent a recurrence on their own. The only thing that consistently prevents a recurrence is neutering.
The Cystinuria Project
The SDCA has partnered with the University of Pennsylvania to understand cystinuria in Deerhounds. The project has two objectives: 1) finding the genetic mutation that causes cystinuria in our breed and 2) developing a quantitative urine test that can detect the disease before a dog blocks. The genetic research is ongoing, and the urine test has been developed and is currently being validated. You can read more about the research here.