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Bladder stones in a cat are rather common and
often are derived from fine, granular struvite
crystals. A cat with bladder stones tends to have the
classical symptoms of feline lower urinary tract
disease: straining to urinate, bloody urine, urinating
in unusual places, genital licking. In the course of
testing to pursue these symptoms, a radiograph is taken and
a stone or group of stones is seen in the urinary bladder.
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
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. 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
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 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
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.
A very good choice for some cats (and some stones) is to
dissolve the stone with a special diet. This avoids
surgery. It is not successful for all trypes of stones, it
is slow (it may take several weeks or a few monyhs to
dissolve a large stone, and not all cats will eat the
Prevention is possible in may cases and 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. . 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 permits veterinarians
to determine if a special diet will be helpful in
preventing recurrence. If a bacterial infection causes
stone formation, it is recommended that periodically
urinalyses and urine-cultures be performed to determine
when antibiotics should be given.
If you have any questions regarding urinary tract
infections or bladder stones, please contact your local