Bladder Stones & Urinary Tract Infections in Dogs
Bladder Stones in Dogs & Cats
By Jennifer Browning-Stone
Information Specialist University of Illinois College of Veterinary
Urinary tract infections are a very uncomfortable problem for humans and
animals alike. In pets, especially cats, urinary tract infections can
sometimes be accompanied by bladder stones, which can both initiate and
promote infection in the bladder.
Dr. Christine Merle, a veterinarian at the University of Illinois College
of Veterinary Medicine in Urbana, says, "While dogs do get urinary tract
infections, cats are much more susceptible." Female cats are also more
susceptible than male cats. This may be because the urethra (opening from the
bladder to the outside world) is very short in female cats, and it is close to
the rectum, where there is a large amount of bacteria. In addition, cats do
more grooming than dogs, which can spread bacteria.
Dogs are usually housebroken, and because they go outside, there is more
opportunity for an owner to notice when there is a problem.
The owner may notice straining or blood in the urine sooner. Infections
often go unnoticed in cats because the owner may not see the cat using the
litter box. Often, cat owners don't notice there is a problem until their pet
stops using the box. Dr. Merle says, "While some cats stop using the
litter box for behavioral reasons, it is important to rule out a medical
problem before assuming that the cause is behavioral."
Since urinary tract infections can be caused by a multitude of factors, it
is often difficult to discover the cause. The origin of an infection could be
as simple as an overgrowth of bacteria or as complicated as bladder stones.
The formation of a bladder stone is very much like the formation of a pearl
inside an oyster. It often forms from a single irritating particle called a
nidus, which consists of a tiny particle such as small bacteria. Minerals are
deposited on its surface, and over time it grows larger and can become very
irritating to the lining of the bladder.
In female cats, these stones can cause recurrent infections with signs such
as straining and blood in the urine. Infections caused by bladder stones often
respond to antibiotics but return once the antibiotics are discontinued.
In male cats, stones can cause infection and, if a bladder stone becomes
lodged in the urethra, make the cat unable to urinate. Such an obstruction can
result in the accumulation of urine in the bladder, which can cause the
bladder to rupture, a medical emergency that is fatal if untreated.
If bladder stones are suspected, it is a good idea to take X-rays and do an
ultrasound examination. Some stones can be seen on a regular X-ray, while
others require ultrasound in order to see them. Ultrasound can also identify
the presence of sandy residue and thickening of the bladder wall, both of
which are signs of possible bladder stone formation.
Because there are several kinds of bladder stones, it is important to find
out what kind of stone an animal has before starting treatment. Some stones
can be dissolved with medication and others, such as calcium oxalate stones,
The only treatment for some stones is surgical removal. Surgically removed
stones should be analyzed so a plan can be made to avoid the recurrence of
stones in the future.
Prevention may include a change in diet, medication, and prevention of
bacterial infections that can lead to the formation of stones. Chronic
problems with stones and bladder infections that do not respond to standard
treatments may require a consultation with a surgeon or specialist.
If you have any questions regarding urinary tract infections or bladder
stones, please contact your local veterinarian.
What are bladder stones?
Bladder stones, more correctly called uroliths, are rock-like collections
of minerals that form in the urinary bladder. They may occur as a large,
single stone or as dozens of stones the size of large grains of sand or pea
Are these the same as gall stones or kidney stones?
No. Gall stones are in the gall bladder, and kidney stones are in the
kidney. Although the kidneys and urinary bladder are both part of the urinary
system, kidney stones are usually unrelated to bladder stones.
What problems do bladder stones cause?
The two most common signs of bladder stones are hematuria (blood in the
urine) and dysuria (straining to urinate). Hematuria occurs because the stones
irritate the bladder wall, causing bleeding from its surface. Dysuria occurs
when stones obstruct the passage of urine out of the bladder.
Large stones may cause a partial obstruction at the point where the urine
leaves the bladder and enters the urethra; small stones may flow with the
urine into the urethra and cause an obstruction in this area.
When an obstruction occurs, urine cannot pass out of the body and the
abdomen becomes very painful. Your dog may cry in pain, especially if pressure
is applied to the abdominal wall.
When there is no obstruction occurring, hematuria, and dysuria are the most
common signs seen in dogs with bladder stones. However, pain usually also
occurs in the bladder.
This is known because when bladder stones are removed surgically, many owners
tell us how much better their dog feels and how much more active it has
Why do they form?
There are several theories of bladder stone formation. Each is feasible in
some circumstances, but there is probably an interaction of more than one of
them in each dog.
The most commonly accepted theory is called the Precipitation
-Crystallization Theory. This theory states that one or more stone-forming
crystalline compounds is present in elevated levels in the urine. This may be
due to abnormalities in diet or due to some previous disease in the bladder,
especially infection with bacteria.
When the amount of this compound reaches a threshold level, the urine is
said to be supersaturated. This means that the level of the compound is so
great that it cannot all be dissolved in the urine, so it precipitates and
forms tiny crystals. These crystals stick together, usually due to mucus-like
material within the bladder, and stones gradually form. As time passes, the
stones enlarge and increase in number.
How fast do they grow?
Growth will depend on the quantity of crystalline material present and the
degree of infection present. Although it may take months for a large stone to
grow, some sizable stones have been documented to form in as little as two
How are they diagnosed?
Most dogs that have bladder infections do not have bladder stones. These
dogs will often have blood in the urine and will strain to urinate, the same
symptoms as a dog with bladder stones. Therefore, we do not suspect bladder
stones just based on these clinical signs.
Some bladder stones can be palpated (felt with the fingers) through the
abdominal wall. However, failure to palpate them does not rule them out.
Most bladder stones are visible on radiographs (x-rays) or an ultrasound
examination. These procedures are performed if stones are suspected. This
includes dogs that show unusual pain when the bladder is palpated, dogs that
have recurrent hematuria and dysuria, or dogs that have recurrent bacterial
infections in the bladder.
Some bladder stones are not visible on radiographs. They are said to be
radiolucent. This means that their mineral composition is such that they do
not reflect the x-ray beam. These stones may be found with an ultrasound
examination or with special radiographs that are made after placing a special
dye (contrast material) in the bladder.
How are bladder stones treated?
There are two options for treatment. The fastest way is to remove them
surgically. This requires major surgery in which the abdomen and bladder are
opened. Following two to four days of recovery, the dog is relieved of pain
and dysuria. The hematuria will often persist for a few more days, then it
stops. Surgery is not the best option for all patients; however, those with
urethral obstruction and those with bacterial infections associated with the
stones should be operated on unless there are other health conditions that
The second option is to dissolve the stone with a special diet. This avoids
surgery and can be a very good choice for some dogs. However, it has three
- It is not successful for all types of stones. Unless some
sand-sized stones can be collected from the urine and analyzed, it is not
possible to know if the stone is of the composition that is likely to be
- It is slow. It may take several weeks or a few months to
dissolve a large stone so the dog may continue to have hematuria and
dysuria during that time.
- Not all dogs will eat the special diet. The diet is not as
tasty as the foods that many dogs are fed. If it is not consumed
exclusively, it will not work.
Can bladder stones be prevented?
The answer is a qualified "yes." There are at least four types of
bladder stones, based on their chemical composition. If stones are removed
surgically or if some small ones pass in the urine, they should be analyzed
for their chemical composition.
This will permit us to determine if a special diet will be helpful in
preventing recurrence. If a bacterial infection causes stone formation, it is
recommended that periodic urinalyses and urine cultures be performed to
determine when antibiotics should be given.
Why Bladder Stones and Crystals
form in Dogs & Cats
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Why Tippy no longer has Bladder Stones
I know all about bladder stones...OUCH!!!
I got them twice. Thankfully the first time my vet did a good job removing
them surgically. He put me on a special diet that was supposed to prevent them
from happening, but guess what?
Two years later, back to the vets I had to go to get more of them removed.
So much for the Hills SD. Besides, I really didn't like the taste of that
stuff and it had this terrible toxic chemical in it called ethoxyquin.....
Oooooh, it makes my hair shed just thinking about how that stuff made me feel.
Anyway the second time I had them stupid stones, I almost died. I hurt sooooo
bad and couldn't move around and had blood in my urine...I felt awful.
So back to the vets I went...I Hate going to the vets!
He kept me for a long time, then I had to go back and stay cause the stitches
came loose and all my inards fell out on the floor. Dave freaked out
and rushed me back to the vets in the middle of the night.
Finally, finally I came back home for good, but it was a long time before I
got to feeling better.
In the meantime, Dane felt really bad and got to doing some serious
research on what's really in commercial pet food.....What A Shocker!!!
So Dave found this food called Life's Abundance. He bought a bag of it and the
Daily Supplement and the Agility supplement (cause I had beginning arthritis
symptoms) and .......
Let me tell you this...WOOF WOOOF WOOOOOF!
Man oh man did I ever start feeling better, and quick. Now I have more energy
than most dogs half my age and I no longer limp around and I can now easily
jump up into Dave's big truck and I run, yea you got that right...Run up the
I love to chase cows and I can now run faster than any of those funny looking
bovines....they're scared of me and I do a great job at keeping them off the
fences and in the pasture where they belong. They don't dare get out with me
Dave's got this big, I mean really big bull. he weighs about a ton. But I'm
not scared of him. I get right in his face and make him move where I want him
to go! HAH!
Of course, I now expect and Deserve to get the very best food, supplements,
and treats. You know it pal, I want treats, and I want good quality treats
So Dave gets them for me cause he knows now that giving me a high quality
food like the Life's Abundance will help me live the longest life possible and
keep me the healthiest I can be.
Go here and try the Daily Nutritional System for your dog or cat, I know you
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