Introduction
A serious problem in cats, especially males,
is called Feline Lower Urinary Tract Disease. It is sometimes also called by
its previous name, Feline Urologic Syndrome (FUS). It is a disease of the urinary
tract that is sometimes related to the buildup of crystals, leading to inflammation
of the lining of the urinary bladder and urethra. In many cases there is no
crystal buildup, so dietary changes will be unhelpful.
We have a page on bladder
stones that should be read
in conjunction with this page.
Graphic pictures are also present
on this page as we demonstrate one of the treatments for this
problem- you will be notfied when they are appearing.
Cause
The crystals that form in the
bladder and urethra are caused by many factors, many of which are
poorly understood. They include diet, urinary tract infections, and
others we are not aware of. Fortunately, the dietary factors and
infections can be controlled and even prevented. In a significant
number of cases no cause can be determined. The name of the disease
in this case is called idiopathic FLUTD. Idiopathic means that a
cause cannot be identified at this time.
Two of the more common minerals
that cause these crystals are struvite and calcium oxalate. Struvite
is a combination of 3 minerals; magnesium, ammonium, and phosphorous.
We tend to encounter this mineral combination in young adult cats.
They are usually treated with diets to decrease the pH of the
urine.
Calcium oxalate is the other
common mineral. It tends to occur more in older cats. They are
usually treated with surgical removal when found in the urinary
bladder.
DietOne of the predisposing factors in FLUTD
is the magnesium (ash) content of the diet. It used to be thought that diets
low in magnesium are particularly helpful in preventing the struvite crystal
problem. This is not true in most cases, it is the change in urine pH from
alkaline to acidic that prevents struvite crystals. In spite of this, many
cat foods have restricted magnesium. Unfortunately, this diet can predispose
to calcium oxalate crystals. After many years of treating cats with this low
ash food we are starting to see an increase in calcium oxalate crystals for
this reason. This is another example of how subtle changes in physiolgy, that
make sense at first glance and are used successfully for many years, can have
untold manisfestations later.
Urine pHIt has been found that the the higher the
pH (the more alkaline) the greater is the tendency for struvite crystals to
form. High quality cats foods help keep the pH in the acidic range, helping
to prevent struvite crystals from building up. Unfortunately, this acidic
(low pH) urine now predisposes cats to calcium oxalate crystals. As a matter
of fact, we are starting to see these crystals more commonly than struvite.
They also tend to form with excess use of cortisone.
It is important to know the pH of the urine to determine the best way to prevent
buildup of crystals. For an accurate determination, the pH of your cat's urine
needs to be measured immediately when removed from the bladder. Getting a
urine sample at home, and checking the pH later is not an accurate indicator
of the true pH of the urine.
Infection
Urinary tract infections might
predispose cats to getting this disease, although it is difficult
to prove this. Even though it is rare to culture bacteria from the
urine in these cats, they do respond to antibiotics. Yet many of
these cats get better without antibiotics. Viruses are implicated
as a cause of this disease also.
This is typical of a urine culture
from these cats. After 48 hours of trying to grow a bacteria from
the urine sample there was no growth.
The MIC stand for
Minimum Inhibitory Concentration-this is the amount of
antibiotic needed to kill this bacteria, if a bacteria
had been culture out.
Cysto is an
abbreviation for cystocentensis, the manner in which
we obtain the urine from the urinary
bladder.
Symptoms
Urine pHCats with the non obstructed
form of this disease will typically be straining to urinate
(stranguria), have blood in the urine (hematuria), or producing
small amounts of frequent urine (pollakiuria). These symptoms can
be subtle and easily missed, especially in cats that urinate
outside. It is easy to confuse these symptoms with a cat that is
constipated. In the male cat this problem can progress to the
obstructed form of the disease, which is a medical
emergency.
Other symptoms might include
poor appetite, uncomfortable or in pain when petted or picked up,
or lethargy.
Obstructed
Form
When the quantity of crystals
progresses to the point that a plug is formed then a cat becomes
obstructed. This amorphous plug is not the same thing as a
bladder
stone. In most cats the
plug that forms is made up of struvite crystals.
Cats without crystals in their urine can
also get the obstructed form of the disease. This form of the disease is seen
almost exclusively in male cats due to the substantially smaller diameter
of their urethra. There will be repeated trips to the litter pan with straining,
and crying in pain upon attempting to urinate. Again, these symptoms can be
confused with constipation. Sometimes a few drops of bloody urine are produced,
although many cats cannot urinate at all.
As the problem progresses these cats start
vomiting, become depressed and dehydrated, and stop eating. as the problem
progresses over several more hours the kidneys
are unable to function and dangerously high levels of phosphorous and potassium
build up in the blood stream. If not corrected, the affected cat will die
from a buildup of toxins or cardiac arrest due to the high potassium.
Since all these symptoms are
variable and can be quite subtle, the important point to remember is
to observe your cats urinary habits on a daily basis and have your
pet checked if there is any change to these habits. The symptoms of
FLUTD can mimic other diseases, so an accurate
diagnosis is
imperative.
Diagnosis
A thorough history and physical exam go a long way towards
making this diagnosis. Urine samples, blood
samples, and even x-rays are used in some cases
to verify the diagnosis and eliminate other diseases that can cause similar
symptoms. Urine samples can be hard
to obtain because these cats urinate as soon as urine fills the bladder due
to the inflammation caused by the crystals. The FeLV
and FIV
status of all cats should be known, so these tests might be included also.
This
is a picture of a cat's abdomen. It is laying on its right side
and its head is towards the left. The large, round and whitish
area towards the right is the urinary bladder (B) that is
distended because it cannot urinate. Compare it to the normal
sized bladder below.
The normal
sized bladder (B) in this cat is much smaller. In addition you
can see the Large Intestines (L.I.) and the kidney (K). The
small intestines (S.I.) are all the round and whitish objects
at the bottom of the abdomen below the large intestines.
Urine
samples can be useful. This one shows that there is
blood in the urine an no bacteria are noted. This is
typical of FLUTD.
Treatment Diagnosis
Unobstructed FormMany cats will get better
without any therapy at all, usually within 7 days.
For years these cats were
treated with a food that acidified the urine. This food has been
the gold standard for treating cats with this problem, and has
helped many cats get over this disease. This acidification can be
harmful though, especially in a cat withkidney
disease. It can also predispose at cat to getting calcium
oxalate bladder stones.
The use of antibiotics in
general is not recommended because bacteria are rarely cultured in
the urine in younger cats. Indiscriminate use of antibiotics in
these young cats can cause the appearance of resistant bacteria.
Older cats will get a urinary tract infection due to bacteria .
This infection might be related to several disease syndromes,
especially sugar
diabetes,
feline
hyperthyroidism, and
kidney
disease.
Other medicines include
cortisone to decrease inflammation and tranquilizers and
antispasmodics to minimize muscle spams of the bladder and
urethra. None of these medications have been definitely proven to
limit the course of the disease. In addition, they all have the
potential to cause side effects. Their use might be indicated as
long as they do not cause more harm then good.
Oftentimes we give fluids to
help flush out the urinary tract and maintain a proper state of
hydration. This is a great way to help these cats, especially
since there is negligible chance of problems, and we are treating
them in a natural way without the use of drugs.
For cats with struvite crystals
Hills C/D-S is the food to use. Cats with calcium oxalate crystals
should be fed C/D-O
obstructed FormIf not detected early and
observed carefully, the unobstructed disease can rapidly progress
to a full obstruction of the urinary tract, especially in males.
This causes acute
renal failure, and will
lead to death if left untreated.
These cats need emergency
intravenous
(IV) fluids and a
urinary catheter placed in the urethra. These pets also need
anesthesia
for us to be able to pass the urinary catheter into the urethra
and start the flow of urine again.
The following graphic
pictures show such treatment.
An intravenous catheter is placed in the cephalic vein located
in the front leg. It is thoroughly wrapped and will be a crucial part of
the treatment. These fluids will minimize the anesthetic risk to kidneys
that are already severely compromised and will also allow the flushing of
the crystals out of the bladder. These fluids will rehydrate a dehydrated
cat, and also flush out excess potassium which can cause serious problems
and even death.
When the
fluids are running and the patient is properly sedated, an
attempt is made to remove the urethral plug. In some cats
gentle massage of the urethra accomplishes this task. In most
cases, a sterile small gauge IV catheter or lacrimal canula is
used to gently flush out the crystals that are lodged in the
urethra. This part of the procedure can take the most time
because the flushing has to be gentle, yet the crystals can be
almost solid in nature.
When the plug
is completely flushed out of the urethra the urine will
immediately flow from the distended bladder. Often times it has
blood in it. In this picture the urine stream is going from the
urethra on the left into the bowl on the right.
When
almost all of the urine has flowed out of the bladder a special
male urinary catheter is placed in the urethra and sutured into
place. It will stay in from 1-3 days in most cases. Some cats
do not need this catheter if their obstruction was minor and
they have an adequate urine flow after their obstruction is
removed.
The urinary
catheter will be hooked up to a collection bag to monitor urine
output. Keeping the catheter in the urethra will let the
distended bladder rest so the injured muscles can return to
normal function faster.
Here is our
patient waking up from anesthesia with catheters in his vein
and his urethra. Even though these catheters can be
uncomfortable, just relieving the pressure on the bladder and
allowing the kidneys to function properly again are a
tremendous source of relief.
Most cats respond rapidly to treatment and can
have their urinary catheters removed 24-48 hours later. They will
remain in the hospital and be closely monitored for urinary output.
On occasion they can re-block and need to have their urinary catheter
replaced.
Cats that have had their bladders distended
significantly before they were unblocked can have a difficult time
urinating after they are unblocked. Urination is painful and the
muscles that contract the bladder do not function well initially. The
cats will be put on medication to minimize straining and our nursing
staff will gently express the urine from their bladders when it
starts to build up. If they don't eat well we will assist
feedthem. Most of these cats do well and
go home in a few days. Sometimes we need owners to express the
bladders at home also.
As a general rule cats with struvite crystals should be fed
Prescription Diet S/D for 30 days to help dissolve crystals that remain in the
urinary bladder. Then they are switched to Prescription Diet C/D or Science
Diet Feline Maintenance on a long term basis.
Surgical Treatment
Some cats re-block continually in spite of
prevention measures. Also, some cats are so severely blocked the first time
that it is impossible to flush the crystals out of the urethra and place a urinary
catheter to allow the flow of urine again. These cats need a surgery called
a perineal urethrostomy, which in essence is a partial amputation of the penis.
The penis is amputated far enough back to the point that the urethral opening
is larger and there is minimal chance that a plug can accumulate and cause a
blockage.
Prevention
Keeping your cat active and in
good health goes a long way to preventing this problem, especially if
it is obese. Keeping the litter pan clean and giving your cat access
to fresh water at all times will also be helpful in prevention.
The most important thing you can do is to make sure your cat is
drinking adequately. The diuretic effect of adequate hydration
goes a long way towards preventing this disease. If need be, give
your cat supplemental water with a syringe or feed a canned
food.
Cats in general maintain an acidic
urine. a normal response to eating is to produce an alkaline urine
initially. Medically this is called post-prandial alkalosis. If
struvite crystals are implicated, this alkalosis will add to the
problem. To minimize post-prandial alkalosis keep food out at all
times (called ad libitum feeding).
Feeding the proper food,
especially if crystals are implicated as a cause, is also an
important preventive measure.
Cats that have had an episode of
FLUTD should be examined by one of our doctors and have a urinalysis
performed at least every 6 months.
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