Cystitis, also known as
Interstitial Cystitis, refers to inflammation of the bladder wall
leading to painful, frequent voiding of small amounts of urine.
This is one reason why clumping (scoopable) litters should be used.
Scoopable litters will enable the feline caregiver to keep track of the
size of the urine clumps to see if they are smaller than usual,
as well as the number of urine clumps to determine if the cat is
urinating more frequently than usual.
Cats with cystitis will often
have many small urine balls in the litter box.
the cystitis is severe enough, there will be blood in the urine but this
blood is not readily apparent once the urine is voided into the litter.
The presence of blood in the urine does *not* necessarily mean that
an infection is present.
Cystitis can be a very painful condition!
The patient will often
start to associate the litter box with his/her pain. This can lead
to litter box aversion which causes the patient to urinate elsewhere.
In these cases, there may be fewer urine balls in the litter box than
These cats need pain medication such as buprenorphine (Buprenex).
What causes cystitis? I
wish that the veterinary community knew the answer to that question in
What we do know is that
cystitis often appears to be linked to stress and
the highly concentrated urine that results from being fed a
water-depleted (dry food) diet may also be a significant factor in some
The concentration of urine is reflected by the urine specific gravity
(USG) number found on the urinalysis report. The higher the number,
the more concentrated the urine.
(See the Urinalysis/Dietary
Issues section below for information and a video regarding how to
obtain a urine sample from your cat for a USG measurement.)
We know that bladders
are 'happier' with more water flowing through them which helps to flush
out debris (mucus, cells, crystals) and keep the urine diluted. Dilute urine is thought to
be less irritating to the bladder wall. Therefore, we see far more
cases of cystitis in dry food-fed cats than in cats eating canned food.
We also know that 99% of cystitis
cases in otherwise-healthy patients are
*not* due to a bladder infection -
contrary to popular belief. The erroneous belief that cystitis is
always secondary to an infection leads to the rampant abuse of
It is very troubling to
witness the very common practice of 'shotgun' treating these patients
with antibiotics when most of these cases are 'sterile' (sterile = no
It is also very frustrating
to see these poor cats leaving the veterinary clinic with no pain
To repeat: We know that
stress plays an important role in the cause of cystitis. Can you
think of anything more stressful than pain?
See the vicious cycle?
Stress can cause cystitis. Cystitis is painful. Pain is
Crystals are not
thought to be a significant cause of cystitis. This is another
very common misconception among both lay people and veterinarians
leading to, in many cases, inappropriate usage of acidifying
prescription diets which can potentially lead to calcium oxalate stones
and exacerbate the bladder inflammation.
That said, dietary management
must be considered on a case-by-case basis and one-size-fits-all
recommendations with respect to diet composition cannot be given.
That said, I will give one 'one-size-DOES-fit-all' statement and that is
"canned food is always better than dry food due
to the appropriate water content in canned foods."
Bladder stones (aka
"uroliths" or "cystoliths") may or may not contribute to cystitis.
However, it is important to examine the urinary tract with radiographs
or ultrasound to look for stones. Due to the expense, some people
opt to not radiograph or ultrasound the cat on the first visit but,
given how common stones are, I would highly recommend checking for
stones even on the first visit.
ultrasound each have their pros and cons with respect to imaging
the urinary tract and the accuracy/usefulness of each examination method
depends on the quality of the equipment and the skill of the operator.
Radiographs - providing there
is not a lot of stool in the colon to obscure the view - may reveal a
stone in the urethra, whereas U/S will not show this area.
Ultrasound exams have some
benefits over radiographs but it is also very highly dependent on
operator skill. Ultrasound can pick up stones that may not show up
In some complicated cases,
both imaging methods are needed to obtain a diagnosis.
Treatments for sterile
increasing water consumption
with a canned food diet, etc.
decrease the patient's stress
- not always easy since cats can be very 'silent' in their stress and we
may not always be aware of what is bothering them
sulfate/hyaluronic acid products such as injectable Adequan, or oral products such as Cosequin, Dasequin, or Trixsyn may help
but studies have not supported them as being beneficial. That said,
they don't seem to have any downsides and may be worth a try.
Tricks used to increase water
flavored waters such as
tuna water, chicken or beef broth, clam juice, lactose-free cat milk
(CatSip), etc. - can be kept in covered (to
prolong fresh smell and taste) ice cube trays
add plain water to
canned food - ~1 TBS per meal - or whatever amount your cat likes
You can make your own tuna
water by taking a can of tuna and adding 3 cups of water.
Break up the tuna and let it sit for awhile (~15 minutes, give or take)
and then pour the tuna water into
covered ice cube trays.
3 cups of water fills two 16-cube
After warming the flavored
ice cubes to 'mouse body' temperature you can:
add to canned food
set out as a separate
drink of water
may also need to be administered at home by the owner in order to
increase urine flow. However, this can be stressful and is usually reserved
only for severe cystitis cases involving dry food addicts that
are on their way to transitioning to canned food.
To repeat a very important
point: Bladder infections are not a common cause of
cystitis. Sadly, the
rampant abuse of antibiotics when addressing feline urinary tract
issues in cats shows that this fact is being ignored. The most important 'treatments' are increasing water
consumption and lowering stress.
Cats, unlike other species
including humans, have a natural defense mechanism in which they produce
a more highly concentrated urine. (USG >1.040)
Few self-respecting bacteria want to float around in concentrated cat
Before considering the use of
antibiotics in cystitis patients, a culture and sensitivity (C
& S), in addition to a standard urinalysis, should be
run on urine obtained via cystocentesis. This involves a
needle going through the abdominal wall, directly into the bladder.
This sounds much worse than it really is. The patient does not
feel the needle going in but, instead, may simply object to being held
on his or her back.
'Free-catch' urine samples
(urine voided onto an exam table or into a litter box) should not be
used for a C & S due to the issue of contamination which will often give
a false positive result. In other words, bacteria will grow on the
culture that may not even be in the patient's bladder or kidney.
The 'culture' part of this
test shows if an infection exists or not. The 'sensitivity' part
of the test is run only if a bacterial colony grows. This half of
the test tells us which antibiotic is the best one to choose for the
type of bacteria that was grown.
One difficulty that we run
into when trying to get a 'clean' sample (via cystocentesis) from a
cystitis patient is that most of these patients present with an empty
bladder. Or, they void all of their urine once the veterinarian
starts to palpate (feel) the bladder through the abdominal wall.
To get around this, the
patient can be given a dose of pain medication and adose of
subcutaneous fluids and placed in a cage without a litter box for 1-3
hours. This should result in the patient's bladder filling up enough to
obtain a sample for a urinalysis and a C & S.
A note about cost:
Many veterinarians do not run a C & S on their cystitis patients
because they are worried about running up a client's bill.
However, I cannot stress strongly enough that this is often a 'pay me
now or pay me later' issue.
I have seen countless cases
where both the veterinarian and the client are 'chasing their tail' by
pouring needless antibiotics into their sterile cystitis
patients. This not only results in added expense and stress for the
client, but please also consider the added stress to the patient's mind
and body and the significant potential for promoting bacterial
resistance. Most cats are not happy about taking medications and
all medications have negative side-effects.
This "tail chasing" often
results in far more cost to the client than would have been incurred if
a C & S would have been run when the patient first presented with
There is a joke in veterinary
medicine that states: "Sterile cystitis patients get better in 1
week with antibiotics and in 7 days without antibiotics."
The good news is that
cystitis often resolves within a few days to a week.
The bad news is that it tends
to recur - especially in patients that are fed dry food and/or continue
to live in a stressful environment.
See below for further
discussion of Urinary Tract
The urethra is the tube that drains urine
from the bladder to the outside. It can be partially or completely
blocked with mucus, stones, inflammatory cells, or crystals. This is
a life-threatening - and very painful - condition which can result in the bladder rupturing
within 24 hours of a complete urethral obstruction - leading to death soon
Any cat that is
repeatedly entering the litter box but not voiding any urine is in need
medical attention! This
is one reason why it is so important to use a clumping (scoopable)
litter. Clumping litter allows you to see just how much, if any, urine
is being voided.
Males are much more prone to
'blocking' than females because the male urethra is much longer and more
narrow than a female's.
The following pictorial shows
what "Opie" had to go through when he blocked. It is highly unlikely
that he would have had to suffer like this if he had been fed a proper, species-appropriate diet of water-rich
cannedfood instead of dry food. Opie was found
lying in a backyard crying - minutes away from rupturing his bladder due
to a urethral obstruction.
A one week stay in the
emergency clinic resulted in a $4,000 vet bill. Another
$350 bill was incurred 3 weeks later when Opie had to have a
stricture broken down in his urethra. Catheterization of the
delicate urethra can damage the tissues and result in a stricture which
will obstruct urine flow. Repeated catheterizations can set your
cat up for some very serious problems.
Opie's case is a very good illustration of the fact that proper
nutrition (NO dry food) is a 'pay me now or pay me later' issue.
sedated and a catheter
was passed up his urethra in order to break up the obstruction before
his bladder ruptured. His bladder was then flushed to try to
remove any debris that could cause him to block again.
Is it possible for a cat to
block when on a 100% canned food diet? Yes, it is possible, but it
is highly unlikely. When water is flowing through the bladder,
crystals, mucus, and cellular debris will be much less apt to build up and cause
Also, when water is flowing
through the bladder, the urine is more dilute which is thought to be
less irritating to the bladder wall in some cats. Less irritation means less
inflammatory cells and mucus to block the urethra.
canned food as rinsing out your
cat's bladder many times each day.
A procedure called a perineal
urethrostomy (PU) is often performed on blocked cats with the hope of
preventing future obstructions.
A PU removes the penis and
part of the urethra and leaves the patient very prone to urinary tract
infections for the rest of his life. Also, the surgery site can
stricture at a later time.
I strongly believe that this
procedure is performed far too early in many cases before a properly
hydrated diet is tried. Please give this procedure a lot of
thought before consenting to it.
November 2013 update: In
December 2012 I consulted with 6 owners of blocked cats over a 10-day
period of time. (Yes, this cause of suffering is that common...)
Unfortunately, one was unable to get to a veterinarian in time and his
bladder ruptured resulting in death.
The other 5 cases were being 'threatened'
with penis amputation (PU surgery) by the primary care veterinarian.
I am happy to report that, one year later, all cats are doing well -
with their penis intact. They are, of course, eating only a
water-rich diet and no dry food.
Urinary tract infections can occur
anywhere along the tract from the kidneys to the urethra. Most infections
gain access to the bladder when bacteria travel up the urethra from the
outside world. From
the bladder, the infection can ascend to the kidneys.
note that when the abbreviation "UTI" is used, the 'I' must be defined.
mean infection? Or does it mean inflammation?
It is very important to
understand the difference if we are to stop
overusing antibiotics and start using more pain medications
when cats exhibit signs of urinary tract problems.
Studies have shown that
otherwise healthy cats (no kidney disease, diabetes, or hyperthyroidism)
- that are showing signs of urinary tract discomfort - have only a ~1-2%
chance of having a UT infection yet antibiotics are prescribed very
frequently for these patients. The veterinary (as well as human)
medical community needs to
address this very serious problem involving the overuse/abuse of
Roughly 99% of these
otherwise healthy cats have sterile (no infection) cystitis. This is
because the feline is very good at saving water to stay hydrated which
results in a very concentrated urine. (Urine Specific Gravity (USG)
>1.040) Concentrated urine is a very hostile environment that
does not readily support bacterial growth. Therefore......
tract infections are rare in cats without a concurrent disease such as
kidney insufficiency, diabetes, or hyperthyroidism.
What about the other
population of cats with diseases such as kidney insufficiency, diabetes, or
hyperthyroidism? Cats with chronic kidney disease (CKD) and
hyperthyroidism often produce a more dilute urine (USG <1.030) which is a
friendlier environment for bacteria. Unregulated diabetic cats
often have glucose (sugar) in their urine which makes a nice culture
medium for bacteria.
However, even cats with
CKD, hyperthyroidism, or diabetes that are showing signs of lower
urinary tract disease have a less than 30% chance of having a urinary
tract infection. (Several studies have been done in this area and
the results have varied but all have shown less than 30%.)
This fact illustrates why it is very important to run a culture and
Culture and Sensitivity
As described above in the
Cystitis section, this is a two-part test that
is used to check to see if an infection is present
(culture) and what antibiotic(s) would be the most appropriate to use
for the strain(s) of bacteria present (sensitivity).
Please note that I emphasized
"if" in the previous sentence. It is very important to confirm
that an infection actually exists rather than to subject your cat to
the administration of an unnecessary, and potentially dangerous,
antibiotic without proof that it is needed and is the correct one.
Culture results are reported
over a period of 3 days - at a minimum. The typical sterile
cystitis report will read:
24 hours - no growth
48 hours - no growth
72 hours - no growth
If there is an infection
present, the report will read something like "moderate growth of e.coli
- sensitivity pending." This means that the next report will give
your veterinarian important information necessary to pick the best
antibiotic for your cat's infection.
Cultures can be classified in
1) diagnostic - the
initial culture before starting antibiotics to confirm that an
infection is present and to identify the bacteria, assess the number of
bacterial colonies to quantify the level of infection (cfu - colony
forming units per milliliter of urine), and to determine the organisms'
susceptibility to various antibiotics
2) therapeutic -
performed 3-5 days after starting antibiotics (after a positive
diagnostic culture) to assess antibiotic efficacy or it is sometimes
performed 3-5 days before cessation of antibiotic administration
3) surveillance -
performed 7-14 days after the last antibiotic dose to check for relapse
Relapses are defined
as recurrences caused by the same species and strain of microorganism
that were found in the diagnostic culture within several weeks of
stopping antibiotic therapy.
defined as recurrent UT infections caused by a different organism. The
only way you can differentiate relapses from re-infections is to compare
the results of the initial culture obtained prior to antibiotic usage to
those of cultures obtained during and/or after discontinuation of the
Relapses represent antibiotic
treatment failures that may result from improper antibiotic choice, dose
and duration of therapy, lack of owner or patient compliance, failure of
the patient to absorb an orally administered drug, deep-seated
infections, failure to identify predisposing factors, or acquired drug
Re-infections, on the other hand, usually represents failure to recognize
and eliminate predisposing factors associated with continuing
dysfunction of host defenses, or UT infections caused by procedures such
as catheterization or perineal urethrostomy (PU) surgery. Frequent re-infection is an absolute indication to
evaluate the patient for anatomic, metabolic, and immunologic disorders
that may compromise normal host defenses.
It is important to understand that when a
cat has had his penis amputated (PU surgery) a vital barrier to
infection has been removed.
For a patient's first time
infection, therapeutic and surveillance cultures are not usually
performed due to cost and added stress for the patient. However,
they should be considered in all recurrent UT infection cases, otherwise
the veterinarian and owner may find themselves running in circles.
To repeat an important point:
Cats with a urine specific gravity above ~1.040 have a very low
chance (~1-2%) of having a urinary tract infection.
Cats with a USG below
~1.030 have a higher chance of having an infection.
If a patient presents with
lower urinary tract signs, and has a low urine specific gravity or is a
diabetic cat that is spilling sugar in his urine, and if
an in-house analysis of the urine indicates that an infection may be
present, the patient may be started on a broad spectrum antibiotic
pending the C & S result.
If the culture turns up
negative, the antibiotic can be discontinued. Or if the culture
comes up positive but shows that the bacteria are resistant to the
antibiotic that has been chosen, the correct antibiotic can be started.
At least in these cases, the
needless - or wrong - antibiotic will have been given for only 3 days
instead of for a much longer period of time.
A quick note on the
long-acting antibiotic called Convenia. Because this drug
stays in the body for a very long time (up to ~60 days) it is one of the
newest antibiotics to be terribly overused/abused. Veterinarians and lay
people are seeing it as a quick and easy fix to their problems because
they don't have to give it once or twice daily like with other
antibiotics. It is typically given by injection once every 2
weeks. However, keep in mind that if an adverse reaction
occurs, you cannot retrieve the drug from the body.
Convenia can cause severe
anemia, as well as other serious health problems. (Please see the
Convenia - Worth the Risk? webpage on
this site.) There is a report on VIN (Veterinary Information Network)
from a general practitioner who dealt with two cats that died within 10
days of receiving Convenia. They were otherwise healthy cats and
had normal red blood cell counts prior to receiving Convenia.
There is no absolute proof that Convenia caused their deaths but there
is an extremely high index of suspicion that this drug was the culprit.
I also recently dealt with
case of severe anemia post-Convenia in an otherwise healthy cat.
The emergency clinic was able to save the patient's life after a 1 week
stay in the hospital. The bill was over $6,000.
9/1/11 update: I have heard
of 3 more deaths post Convenia. Please do not allow this drug to
be given if the cat is able to be medicated with a safer antibiotic.
I continue to receive reports of serious adverse effects from Convenia.
Baytril is another
antibiotic that is frequently abused. This drug can cause blindness
(rarely) so I
do not take its use lightly.
Clavamox is the most
common broad-spectrum antibiotic that is administered to cats. It
causes vomiting and/or diarrhea in some cats but it is one of the safer
choices of antibiotics. It comes in pill or liquid form. I greatly
prefer the pills because they are very palatable and can be crushed and
added to canned food, or administered in a small piece of a Pill Pocket.
(Never use a whole Pill Pocket since they are too big making it far more
likely that the cat will bite down on the pill versus swallowing it
whole.) I do not like 'pilling' cats so if your cat will not eat crushed clavamox
tablets in tasty canned food or baby food or in a Pill Pocket, then use the liquid
formulation. (See the Pilling Cats
webpage on this site.)
Laboratory analysis of urine
can be done on samples obtained in various ways but you need to be aware
that some tests are not accurate on free-catch samples that you have
obtained at home.
Due to the delay in
testing of the sample (by more than 30 minutes once the urine has been
and the lack of sterility of a free-catch sample, interpretation
of a urine sample obtained at home can be very misleading.
One example of a test that
is accurate is the urine specific gravity. This is also one of
the most important numbers on the UA. I routinely
(3-4x/year) check my cats' USG from free-catch samples obtained by
slipping a flat (versus a deep/narrow) tablespoon under them when they
A low USG can be an early indication of kidney
insufficiency so I like to monitor any cat over 10 years of age several
times each year.
Watch this video for information regarding
obtaining free-catch urine samples:
When assessing a patient's
urine concentrating status, it is always much better to take multiple
readings so that you can see an average over time - versus relying
on just one reading, at one static point in time, from a UA report.
Therefore, some people buy their own refractometer in order
to check their cat's USG at home. If you do purchase one, make
sure that it is labeled for use with urine. The RHC-200 ATC
(automatic temperature compensation) linked
has been sold on eBay for as little as $50.
The RHCN-200 ATC is billed as
a "Heavy Duty Version of the RHC-200 ATC and features an
easy-to-calibrate knob" versus the need to use a small screwdriver
(easily lost or misplaced) for the RHC-200 ATC model. Either one
will be fine because you don't have to calibrate the unit very often.
In fact, my 30 year old one has only been calibrated a few times in its
life but I would suggest that you calibrate yours ~once or twice a year
with distilled water which will have a specific gravity of 1.000.
Calibration is very easy. Just apply a couple of drops of
distilled water onto the refractometer window then adjust the
refractor line to 1.000 with the screwdriver or the knob.
A urine culture and
sensitivity is not accurate from a free-catch sample due to
contamination issues. However, on rare occasions we may run a C &
S from a midstream sample that is caught in a sterile container but
interpretation must take into consideration the collection method.
If the C & S comes back negative on a free-catch sample, this result is
helpful but if it comes back positive, you cannot be sure if the
bacteria are from the bladder/kidney or from the very end of the urinary
tract or the patient's hair that surrounds the vulva or penis.
A check for crystals is also
not accurate because crystals can form once outside of the
bladder in as quickly as 20 - 30 minutes. This problem of a 'false
positive' can be an issue with urine obtained from a free-catch sample
at home, as well as one obtained via cystocentesis
that is sent to an outside lab due to the same time delay. If your
vet wants to accurately assess for crystals, the urine must be looked at
'in-house' within 20 - 30 minutes of cystocentesis or the urine being voided.
pH also may not be accurate
in urine samples obtained at home.
A cystocentesis is the best
method to obtain urine which will yield the most accurate results.
A few definitions, along with
pH refers to the acidity or
alkalinity of, in this case, urine. pH is often mentioned when
discussing diet and crystals but is focused on far too heavily.
Grains, on the other hand,
promote a more alkaline urine due to their carbohydrate level as shown
Due to Man's focus
on profit margin,
diets higher in grains (higher in carbohydrates than a cat's natural
diet) have flooded the market - along with pet food manufacturers'
unscrupulous advertising onslaught designed to persuade the feline
caregiver to think that feeding a water-depleted, grain-laden dry food
diet constitutes optimal nutrition.
Keep in mind: Meat is expensive.
Grains are cheap.
Meat (animal-based protein)
promotes a mildly acidic urine which is normal for the cat.
Grains (plant-based protein
and high carbohydrate content) promote an alkaline urine.
As mentioned below in the
Crystal section, struvite crystals are more apt to form in an
alkaline urine and calcium oxalate crystals are more apt to form in an
acidic urine. Many 'urinary tract' diets - including some of the
prescription diets - overly acidify the diet past what would be
normal for a cat eating a species-appropriate diet. These diets
can dissolve struvite stones but will lead to other problems, such as
calcium oxalate stones, if they are
fed past the therapeutic time frame.
Please understand that we
would rarely have to address pH or crystals if cats were fed a
water-rich diet. However, due to the fact that humans insist on feeding cats
species-inappropriate, water-depleted diets in the dry form
they are cheaper and more convenient to deal with and because many cats
are addicted to them, the cat continues to
suffer with urinary tract issues.
For many years, struvite
(magnesium, ammonium, and phosphorus) was the predominant mineral
mixture found in cat urine due to the species-inappropriate level of
grains in cat food. Knowing this, humans stepped in and
started acidifying commercial cat food with things like dl methionine -
instead of cutting into profit margin by removing the grains and going back
The so-called 'urinary tract
formulas' were born.
Unfortunately, in trying to
'fix' a cat's unnatural alkaline urinary pH - caused by human
greed in the first place - pet food manufacturers created even more problems by adding
urinary acidifiers in the form of dl methionine, etc., which led to the
formation of calcium oxalate (CaO) crystals/stones in many cats.
Suddenly, there were far more patients suffering with CaO
crystals/stones than there were patients with struvite crystals/stones.
One of the most serious problems
with this fact is that CaO stones can only be removed with surgery. There
is no way to dissolve them with dietary manipulation. Struvite
stones, on the other hand, are more amenable to dissolution with dietary
Most stones found in the
kidney are CaO and since we cannot dissolve them with dietary
manipulation and since surgery to remove kidney stones (versus bladder
stones) is not a safe option, it is easy to see how damaging the effects
of feeding an acidifying diet can be if used for long periods of time.
Other systemic problems,
including kidney damage and low potassium, can be seen in conjunction with the feeding of these acidifying diets, as
It is also important to note
that diet is not the only factor involved in determining urine pH.
The timing of the cat's meals is also a factor. 'Post-prandial
alkaline tide' refers to the fact that urine pH will become more
alkaline after eating a large meal. Therefore, it is suggest that cats
eat multiple small meals throughout the day to help keep the pH in a
normal range. Small cats in the wild eat 8-10 small meals per day.
pH can also be affected by certain
medications, vomiting, chronic kidney disease, urinary tract infection,
diet, stress, and as already discussed, the timing of the last meal.
If Man would just go back to
feeding cats a species-appropriate diet - i.e. -
one that has a water content that mimics a cat's normal prey and
one that is based on meat, not gains - instead of trying to
artificially manipulate a species-inappropriate diet of grains by
adding acidifiers, the vast majority of urinary tract problems would be
Crystals are most commonly
either calcium oxalate (CaO) or struvite (a mixture of magnesium, ammonium,
Calcium oxalate crystals are
more apt to be formed in an acidic environment.
Struvite crystals are more
readily formed in an alkaline environment.
A small amount of crystals
an abnormal finding in cat urine and the cat should not be
automatically put on a prescription diet such as Hill's Prescription c/d, etc.
Crystals are often
erroneously diagnosed because they can form once the urine has been
removed from the bladder. Therefore, when urine is sent off to
an outside laboratory, or a sample is brought from home, a report of "crystals" is somewhat
meaningless since you have no idea if they were actually present
within the patient. This misdiagnosis - and overemphasis of the
significance of urinary crystals if they are present in the bladder - leads to the client becoming
alarmed and the patient needlessly being put on a low quality - and potentially
dangerous - diet such as one of the prescription 'urinary tract'
Think of crystals in cat
urine like leaves
on your driveway. Both are normal findings. However, if you
never hose (or sweep....during a water shortage :>)) down your driveway,
the leaves will build up and then you won't be able to get your car out
of the garage.
If crystals are allowed to
build up, the urethra can become blocked leading to a life-threatening
situation. A blocked cat can end up with a ruptured bladder -
resulting in death - within 12 -24 hours of complete obstruction.
If there is not enough
water flowing through the bladder on a regular basis the following will happen with respect to
The urine specific gravity
goes up meaning that the urine becomes more concentrated. When
this happens, the crystals are more apt to become 'super-saturated' in
the urine and form stones.
Mechanical removal is
compromised. When there is ample water flowing through the bladder the cat
will urinate more frequently - voiding up to double the amount of urine
per day. This frequent urination of a higher volume of urine helps
to remove the
crystals instead of letting them build up to block the urethra.
If there are large numbers
of crystals and the cat also has cystitis (inflammation of
the bladder leading to mucus production and cellular debris), the
crystals can combine with the mucus and inflammatory cells and make a
'plug' that can block the urethra.
Keep in mind
that it is very important to have enough large litter boxes with CLEAN
clumping (scoopable) litter in accessible places so that your cat is
very willing to use them frequently and not 'hold his urine.'
More frequent voiding of
urine will lower the chances of stones being formed and will make the
bladder wall less likely to become inflamed.
Litter boxes should always be
scooped at least twice daily.
Urine Specific Gravity (USG):
As noted previously on this
webpage, USG is a measurement of the concentration of the urine.
It is one of the most important values on the UA report.
USGs should be measured on more than
one occasion to check for consistency. A dilute USG would be around 1.015
(stated "ten fifteen") or 1.020 ("ten twenty") and a concentrated urine
would be more in the >1.040 range. A USG between these ranges
should be monitored to see if it continues to go lower or starts to
The USG of
dry food-fed cats is higher (the urine is more concentrated) than it is
for canned food-fed cats.
review what I wrote about diet issues at the top of this page in the
grey box and also
keep in mind what was discussed above regarding the fact that urine
crystals are often erroneously diagnosed and the fact that
they are NOT necessarily an abnormal finding that needs to be
'treated' with a prescription diet.
If you need help beyond the scope of this webpage I am available for
but please note that many people write to me asking questions that are
already addressed on this webpage.
That said, there is a lot of
content here and it can be quite confusing. Therefore, if you want
to address it verbally in more detail and also as it pertains to your
own cat, you can contact me for a consultation appointment.
Prior to the
appointment, the patient's medical records must be scanned/emailed to me
for my review.
Advice will not be discussed via email nor without medical records being
I do not use use
diets except in rare cases as noted below. They are expensive and contain low quality,
species-inappropriate ingredients, and are not necessary in most cases
of feline urinary tract disease. I only consider the
temporary use of Hill's canned s/d if I
know the patient has urinary tract stones ("uroliths") - or a large
amount of crystal/mucus/inflammatory cells 'sludge' (especially when the
patient is male) - with a high index of suspicion
for them being struvite versus calcium oxalate (CaO).
Males have a long, narrow
urethra and are much more apt to block than females.
In these cases, I will
consider the use of canned s/d (the most acidifying diet on the
market) for a short period of time until
the patient shows radiographic or ultrasound evidence of stone dissolution/'sludge'
can take as little time as a few days but may take 2-3 months for large
If the stones are not showing
any signs of dissolution once the patient has been on the acidifying
diet for 2 - 3 weeks, there is a very good chance that the stones are CaO and keeping them on this diet
- if the stones/crystals are CaO - is only going to make
matters worse. This is why it is so important to monitor the
patient with radiographs or ultrasound and urinalyses and to not
just leave them on s/d.
Remember, CaO will not
dissolve with diet manipulation and Hill's s/d will actually promote the
formation of CaO - creating a dangerous situation. Surgery is the
only way to remove CaO stones and if they form in the kidney (more
common than the easier-to-access bladder), they cannot be removed
without significant risk to the patient.
'Sludge', in some cases, can
be handled with simply a water-rich diet (canned food with added water) to flush it out but it is possible to
have small stones hiding in this mixture that could be missed on
radiographs or ultrasound and which could result in urethral blockage.
If your cat has a large amount of sludge
in his bladder that you are now addressing with diet (s/d or simply
canned food with added water), be sure to watch him carefully for any
signs of a urethral blockage. I would not want to leave a cat like this
unattended for more than ~12 hours in case he blocked.
Also note that meat-based diets promote
an acidic urine (but not overly acidic like Hill's s/d) and that
carbohydrate-based diets promote an alkaline urine. Keep in
mind that carbohydrates have no logical place in the feline diet.
Other prescription diets such as Hill's
c/d, Royal Canin SO, and Purina UR are diets that do not aggressively
acidify the urine like Hill's s/d does.
Therefore, c/d, SO, and UR can be fed for
life but I would not recommend it due to their cost and unhealthy
Hill's s/d, on the other hand, is NOT
suitable for long-term feeding and should only be used temporarily.
When urinary tract prescription diets were
first formulated, they mainly focused on urinary pH manipulation and
magnesium restriction. In recent years, some of the manufacturers
such as Purina and Royal Canin have added salt to their diets to
encourage higher water consumption in order to dilute the minerals
(crystals). There is controversy surrounding this practice.
Prescription urinary tract
diets come in dry and
canned forms but after reading this webpage, hopefully the reader will
understand just how illogical it is to add salt to a dry food diet to
get the cat to drink more water when the cat should be eating a
water-rich diet of canned food in the first place.
As stated in the first
section of this webpage, manipulating the pH of urine is not the most
important factor in preventing feline urinary tract diseases yet it is
so heavily focused on.
I am finding it increasingly
frustrating to watch the veterinary community continue to be fixated on
the pH of cat urine and the presence of urinary crystals instead of
focusing on the much more important issue of
dietary water content.
are exhibiting a serious lack critical thought when prescribing a
water-depleted diet to any cat but especially one with urinary tract issues.
Instead of reflexively
reaching for the prescription diets when patients present with urinary
tract issues, I would like to see the emphasis switch to getting the
patient off of all dry food and onto a meat-based canned food with added water.
This diet will help maintain a
species-appropriate urine pH and will keep the bladder flushed out.
When I say it is illogical to
feed "any" cat a diet of dry food, think
about practicing preventative nutrition. Do you really want to
wait until your cat develops urinary tract problems before you
implement the feeding of a water-rich diet to a species with an
naturally low thirst drive?
Think about closing the barn
door before the horse is running down the roadway.
Information on this site is for general informational purposes only
and is provided without warranty or guarantee of any kind. This
site is not intended to replace professional advice from your own
veterinarian and nothing on this site is intended as a medical diagnosis
or treatment. Any questions about your animal's health should be
directed to your veterinarian.