Urinary
Tract Infections - by Patricia Long
November, 2001
Edited by Melissa Zebley, DVM
Contributions by: Anne Cervenka, Tim Forman,
Stacey Goodman, Valerie Horney, Susan
Kowitz, Sue Sanvido, Ann Skinner, Rose Tierney, Debbie Tripp, Sherri Venditti,
Sue Wilkinson
What constitutes the urinary tract? It starts in
the kidneys with the waste management plant. The kidneys then excrete urine
into the expandable bladder where it is held for eventual evacuation through
the urethra. In males, the urethra, which also passes through the prostate
gland, is much longer and narrower than in females.
So how does the bacteria
get in there? Cystitis is an inflammation specific to the urinary bladder, and
an inflammation of any part of the urinary system is called a urinary tract
infection, or UTI. A UTI is usually prevented by the normal body defense
mechanisms. The urine flows in one direction, and the surfaces are smooth -
which inhibits bacterial growth. But if the urine is held too long, or if the
animal is unable to void all of it in one steady stream, or there is some
design anomaly, or if the dog has diabetes mellitus, or some type of trauma
created a problem, if kidney or bladder stones form and cause damage, then
bacteria can take a foothold. Once the bacteria starts
growing, the normal workings of the process start to give problems. The feeling
of irritation causes the dog to need to go frequently, often without warning.
Accidents in the house in previously good-as-gold dogs are often an indication
of a UTI. Any blood in the urine (dark orange, brown, or red urine) is also a
sign of definite problems. If the bacteria populates
the bladder, it can cause pH changes in the urine, which then allow for
crystallization of substances that are usually dissolved in urine. Stones can
form, and there are many different types of stones. Changes in pH can also make
the environment more conducive to the growth of bacteria. If the bacteria get
into the kidneys, it can cause damage to the kidney function.
There are several methods used to collect urine
samples for analysis. Probably the most common is for the owner, vet, or vet
tech to collect a sample while the dog urinates. This is known as the free
catch. The down side to this (other than the difficulty in collecting it) is that
the urine also passes through the urethra and other structures, any of which
may contaminate the sample. A second method for collection is by
catheterization. A sterile tube is passed through the urethra into the bladder.
The benefit to this method is that a more accurate sample may be obtained. The
down side is that it can introduce bacteria into what may have been an
uncontaminated bladder, it may also cause irritation to the urethra, or it may
even require sedation. The third method of collection is cystocentesis. A
needle is passed through the abdominal wall directly into the bladder and a
sample is pulled into the attached syringe. This gives the most accurate sample
of urine from the bladder. The risks are the possibility of tearing the bladder
if the dog moves drastically, or of having urine leak into the abdominal cavity
and causing peritonitis. Both of these risks are extremely rare.
Treatment for a UTI is simple - antibiotics. But which one? The type of bacteria can be determined by the
initial urinalysis, and the best antibiotic for the type of bacteria (gram
negative, cocci, or others) can be selected. Different antibiotics generally
work better for specific bacteria, and selecting the antibiotic most likely to
be successful is important to help minimize the risk that the bacteria will
develop a resistance to the antibiotics. If the first choice antibiotic doesn’t
work, then a culture and sensitivity test should be done to select the right
antibiotic.
Treatment should also be long enough. A normal
course of antibiotics is at least 10 days, and 14 or even 21 days is not
unreasonable. Always finish the treatment! Just because the symptoms clear is
not sufficient cause to discontinue the medication. You do not want to have to
take your dog back to the vet with a recurrence of the UTI – which now may be
resistant to the antibiotic that worked the first time!
As for stones, they are nasty creatures that can
block the top of the urethra, or even get down into the urethra and pass out
with the urine. A blockage is life threatening. Symptoms include lethargy and
vomiting. Most dogs get struvite stones, a composition of magnesium, ammonium,
and phosphorus. Dalmatians typically get urate stones. A
third type of stones that dogs will get are calcium-oxalate stones. The
struvite stones can often be dissolved with a special veterinary prescription
diet, such as S/D made by Hill's. It can take a while (a couple of months), but
it can sometimes be done. Most stones caused by the dog's normal metabolism can
be prevented with dietary changes and restrictions. Stones formed because of a
UTI can be prevented by close monitoring for future
UTIs. Stones and UTIs are a classic chicken and egg situation. Determining which came first is difficult, but important to help determine
how best to prevent a recurrence.
One thing to consider.
A dog may have a UTI and you won't even know it. Female dogs will mark
territory, as will males. Is it marking? Or is it frequent urination due to
infection? It can be impossible to tell. If you are in the habit of getting
blood work done for the annual checkup, it might also be a good idea to have a
urine analysis done as well. It can help catch problems much sooner.
All right, the infection has cleared up, and the
dog is still having difficulty peeing! If you suspect stones, some of them can
be detected on x-ray, some can be detected by feel
(palpation). Stones may also be diagnosed by double contrast x-ray or by
ultrasound (which can also help detect structural abnormalities in the bladder).
If the diet doesn't help dissolve them, then surgery may be the best option. It
is surgery, with all the normal surgical risks of course, and it is a bit more
involved than a spay. An abdominal incision, lift out
the bladder and incise it. Remove any stones, run a catheter through the
urethra into the bladder to check for any blockages or additional stones, then
stitch it all back up. Then try to keep it from recurring!
It is worth mentioning vitamin C here. One study
linked massive doses of vitamin C with oxalate stones, since ascorbic acid is
metabolized to produce oxalate. But more recent studies have refuted the
conclusions. It is now evident that intake of massive doses of vitamin C (over
500mg per day) will not make stones either more or less likely. But if oxalate
stones are a problem, it might be wise to avoid vitamin C supplementation since
there is some evidence that ascorbic acid may increase the problems in those
individuals that do produce oxalate calculi (stones).
Experiences from the List:
A special section here needs to be devoted to
the process of collecting urine samples. Lisa Allen notes that it is wise to
ensure that the electric meter reader is not watching before you start the
process of following your dog around with whatever you are using to collect the
urine. I have found a plastic ice cube tray to work well for females, it slides
surreptitiously under the squatting girl, and there is no loud metallic sound
to scare them into stopping the flow. Other recommendations for collection: a
large plate, an aluminum pie pan, a screw cap jar such as Gerber Baby food or a
pickle jar for a dog, a large glass lasagna pan, a small plastic cup held in
clean long barbecue tongs, and a soup ladle. One person devised a remote
collection device by straightening a metal hanger and heating it to attach it
to a plastic Tupperware container about a cup in size. Ideally you want a
sterile receptacle, and if the sample isn’t going in to the vet’s office
immediately, refrigerate it.
Pat Long's
Vesta developed a UTI when she was 9 years old. Bloody urine finally got
cleared with antibiotics. But the frequency of urination didn't diminish. On
x-ray, 2 stones were clearly visible, and S/D was used to attempt to dissolve
them. But Vesta's urethra got blocked, something that rarely happens with
females! She was catheterized, which unblocked the urethra, and surgery was
later performed to remove the stone. She never had a recurrence of bladder
stones, and in all likelihood, the stones were a result of the urinary tract
infection.
Sherri Venditti's Kalila had a chronic UTI from 8 weeks to one year plus. When she was on antibiotics she was fine, within 48 hrs of being off the drugs it was obvious that the infection was back. After evaluation of her lifestyle/environment, lots of tests, rounds of different drug therapies and an IVP; the Kidney Specialist at the veterinary teaching hospital had found no specific cause except for the "possibility" of a "maybe, slightly low" level of one imunoglobulin being a factor. In her opinion, the infection was not "reoccurring" but rather always present at a level kept in check by the antibiotic (hence the diagnosis of " chronic"). The decision was to keep her on Clavamox for the remainder of the year and then "wean" her off slowly and keep our fingers crossed. Thankfully she tolerated the Clav. well and shortly after her first birthday we started reducing the dosage. We were sooooo nervous about finding ourselves back where we started that it was two more months before she was totally off the drug! TAA- DAA... No more infection! In the 8-1/2 years since she has had (2) UTI (a couple of years apart) - both times she was put on the standard regimen for Clavamox and the infection was GONE, just like a 'regular' dog!!!
Valerie Horney’s puppy suddenly went
un-potty trained, it seemed as if he didn't even know
he was going. My suspicions were
confirmed with a urine sample, just follow him around
with a cup! He had a bladder
infection. A bout with the dreaded
antibiotic and it was gone and he was back to his potty trained old self in no
time.
Sue
Wilkinson’s Kellu had recurrent UTI’s from age 3 months
to age 10 months. We took sterile samples & cultured them -- the verdict
always came back as E. coli -- the sensitivity always confirmed that the
antibiotics currently prescribed were doing their job. We confirmed this with mid-treatment &
post-treatment samples/tests. And every
single time, the infection would come raging back within 2 days of
ending antibiotic treatment. We tried a number of different antibiotics and
also Methionine to acidify the bladder environment. We also investigated
initially with abdominal x-rays (no obvious signs of stones, polyps etc.). 2 1/2 months later we did double contrast
radiographs of her bladder -- these showed a small evagination which we
wondered might be forming a pocket of infection. Based on this evidence, we then performed an
exploratory laparotomy and excised a chunk of scar tissue 3 cm in diameter --
her entire bladder was extremely thickened and inflamed (8 mm thick), and we
confirmed there were no stones present and that her kidneys, ureters, spleen
etc. all appeared normal. Histology of
the excised scar tissue was negative -- no signs of neoplasia (whew!). Still, the UTI's came back -- as at the time
there was nothing else my vet could do to investigate (he has an ultrasound
now), Kellu was referred to the
Sue Sanvido rescued a 10 1/2 year old
bitch out of a shelter (can you believe someone dumped a Berner especially at
this age) anyway, she had bladder stones for who knows how long. Surgery was done; she came through with
flying colors and lived another couple of years with no problems.
Susan Kowitz knew something was wrong
with Mercedes when Bentley became feverishly interested in spayed Mercedes.
Mercedes had a urinary tract infection, and after a week of antibiotics,
Bentley returned to normal! Her Bentley also had a bout with a UTI, which was
cleared with antibiotics.
Anne Cervenka’s berner had recurrent
bouts of UTIs until all soy was eliminated from the
diet. She
had
read in a book about human nutrition by Carol Ann Rinzer,
"The Complete Book of Food":
"Production of uric acid: Purines are the natural metabolic by-products of protein metabolism in the body. They eventually break down into uric acid, which forms sharp crystals that may concentrate in joints, a condition known as gout. If uric acid crystals collect in the urine, the result may be kidney stones. Eating dried beans, which are rich in proteins, may raise the concentrations of purines in your body."
Tim Forman’s Gandalf had a problem with
excess discharge which was diagnosed as a UTI. The vet prescribed an antibiotic
and told him that we could expect the problem to recur, perhaps several times,
until Gandalf's immune system matured. After treating him for a second
recurrence with antibiotics, three subsequent mild recurrences were dealt with
successfully simply by adding a daily 1 gram dose of Vitamin C (in the form
pure ascorbic acid powder) to his BARF diet!
Ann Skinner’s Kerzon was being shown in
confirmation when in a practice judging session Ann noticed that one testicle
was smaller than the other. This was a
new occurrence - I took him in to see the vet, who confirmed that the one
testicle was atrophied. I ultimately had
him neutered, to make sure that nothing else was cooking in there. The vet didn't really have an explanation for
what had happened, although he did hypothesize that a urinary tract infection
that Kerzon had sustained several months earlier may have caused scarring to
occur and block the circulation. Fortunately, Kerzon appears very happy and
healthy, and not nearly as traumatized by the event as I was.
Rose Tierney relates that it is not
uncommon for puppies to have UTIs and normal treatment is a course of amoxillin or Clavamox. With
young prepubescent bitches they often have vaginitis which can also cause them
to urinate frequently and may be a little sore. With persistent vaginitis it is
best to let her have her first heat and that usually clears it up, if spayed
beforehand can continue to be troublesome. Have witnessed this "cure"
a number of times but the pet owner might be hesitant about the messiness of a
full heat cycle. This is where boys Y-fronts with Panty liners come in handy
and the tail goes through the Y!! If
however your young girl is actually experiencing repeat UTIs you need to take
her with a full bladder to the vets for a centesis collection for a complete
urinalysis so the appropriate antibiotic can be prescribed. Typical signs of
UTIs are frequent urination and often small amounts, blood may be seen but
normally it is not that obvious. If puppy is urinating several times in one
hour and housetraining seems to have taken a backward step it can be helpful to
collect some urine in a clean container and have the vet test it with a
"dipstick" though a centesis collection is more thorough in
persistent cases.
Many
vets do not like to give Baytril (a very broad spectrum heavy duty antibiotic)
to young developing dogs for fear of damaging their joint development. One of
my vets told me that the tests showing joint
abnormality was done on lab rats and no significant findings were reported with
dogs. However I prefer not to use Baytril freely without specific analysis as
it is such an important antibiotic that might be needed later and one does not
want to build up resistance. Clavamox is
usually the drug of choice for UTIs and Rose has used it on occasion -
sometimes the length of treatment has to be extended.
Stacey
Goodman details that when we or our dogs are put on antibiotics the bacteria
not just in our gut but also in our small & large intestines gets wiped
out. Antibiotics do not differentiate between good & bad bacteria - so
every thing is attacked. I have found it really helps to give them some Pro
Biotics during antibiotic therapy and for a while afterward. Pro Biotics are
concentrated forms of good bacteria normal found in our intestines. They are
fairly inexpensive and easy to give, usually 1/2 to 2 capsules per day an hour
after eating depending on the brand and size of dog. I get the kind that also
has FOS (fructoligosaccharides) FOS is like dirt in that you need
"soil" to plant the bacteria in. Pro Biotics are usually found in the
health food stores in the refrigerated section. Recently I had a bone infection
and had to take some heavy duty anaerobic antibiotics. The antibiotics can
cause severe diarrhea (because of killing all the
intestinal flora). I started taking the pro biotics and was fine by the next
day. They really helped! Acidophilus in yogurt is ok but not really enough. The
pro biotics usually have from 6 to 10 different types of the good bacteria in
them. Be sure to keep them refrigerated.
Many
people on the list recommend cranberry capsules to minimize the risk of UTIs.
Debbie Tripp indicates that dogs that
have chronic UTIs that keep reappearing after antibiotics and/or alternative methods, may actually have bladder diverticulum. This is a congenital defect of the bladder -
a little pouch is on the bladder that collects old urine and grows
bacteria. The urine is not readily
flushed out, so it is old and bacteria can grow and cause infections. It can
(and probably should) be corrected surgically.
Melissa
Zebley, DVM, has offered a great deal of advice about UTIs.
One
of my vet books (Merck) states that 2/3 of UTIs are caused by E.coli OR
staphylococcus spp. However, my
preferred text (Tilley's 5 Minute Veterinary Consult) lists staph, streptococcus
and enterococcus as the most common causes.
Personally, I can't recall seeing a case of an E.coli UTI in an
uncomplicated, first time UTI. And with
my microbiology background, I check what the bacteria are in each and every
suspected case of a urinary infection. And you need to be sure of what you're
treating. While this d-mannose sounds
good, I also know that diabetics have a much harder time with frequent urinary
infections especially because of the sugar in the urine, so I'd definitely be
cautious in treating a UTI that I didn't know for sure had E.coli.
There
are a couple of ways to get a urine sample.
The first, and preferred method if you're going to be trying to culture
the urine, is called cystocentesis - where a needle is inserted directly into
the bladder and urine pulled out. This
gives an accurate and sterile sample.
The
second method is known as free catch.
Using a clean pan or bowl, you place it under the dog as he/she starts
to urinate and catch a sample. If you
can open up a wire hanger and wrap one end around the cup so you have a holder
- this will work easier as the dog is less likely to jump away and look at you
like you're crazy when you try to place the cup under him. Unfortunately, it is
also subject to any contamination in the urethra and/or the cup, so it is not
the best sample for a suspected urinary infection, at least not to
culture. On the other hand, it is the
preferred method of collection when you are trying to rule out prostate
problems in a male dog.
The
third method is urinary catheterization.
This is a bit difficult in the female but easy in the male. It will provide a "cleaner" sample
than the free catch method, but not as clean as a cysto. The negatives
on this is the potential to introduce bacteria into the bladder, the
potential irritation of the urethra, and the need for restraint during an
uncomfortable procedure. (Yes, the cysto is probably not comfortable either,
but the animals don't seem to mind as much, and it's much quicker than passing
a catheter.)
As
for the dog, ideally bring him or her into the vet without letting them
urinate, so they are more likely to have a full bladder. With a urinary tract
infection, this may not be possible due to the frequent urination. So, be
prepared that you may need to leave your dog there for a few hours as the vet
may give the dog some additional fluids (usually under the skin) and/or a
diuretic drug to temporarily increase urine production.
As
for feeding salty foods, yes this would distort the results. Part of what the
urinalysis is trying to determine is how well the dog is concentrating his
urine. If you feed him salty foods,
he'll drink more, thus diluting his urine, and giving a false result. This may cause the vet to think he may have
some kidney problems when he really doesn't.
If
a urinalysis reveals that there is bacteria in the
urine, then systemic antibiotics would be needed. However, you can determine the antibiotics
best suited to the particular infection by what type of bacteria are
present. Personally, I've never used
metronidazole (Flagyl) to treat a UTI, but I just did some looking and found a
reference for its use in treating infections of the male urethra.
And
finally, if you're dealing with a recurrent UTI, then additional diagnostics
are absolutely necessary. It may simply
be that the first round of treatment was not long enough or strong enough to
kill off ALL the bacteria, and the infection recurred. However, often a recurring UTI is a sign of
some underlying problem - such as a physical abnormality like stones in the
bladder or a abnormality in the bladder itself, or a
systemic problem like diabetes. By
continuing to treat a recurring UTI, whether it's with antibiotics or d-mannose
or anything else, you're not addressing the real problem, only a symptom.
Bibliography:
The ROCKet Science of Canine Urolithiasis, edited by Osbrne, Lulich, and Bartges, The Veterinary Clinics of North America, Small Animal Practice, vol 29, No 1, January 1999.
Saunders
Manual of Small Animal Practice, Stephen J. Birchard,
DVM, Robert G. Sherding, DVM; W. B. Saunders, 1st
edition, 1994.
Essentials of Small Animal Internal Medicine, Richard W. Nelson &
C. Gullermo Couto; Mosby, 1992.
The
Merck Veterinary Manual, eighth edition, 1998.
522, 779, 804, 1038, 1215, 1582, 1597, 2542-4, 3067, 3076.