Tract ‘Stones’ & Cystitis in Cats and Dogs
By Dr. Michael
Dietary factors play a major role in the development
kidney stones that can block the urinary tract in cats and dogs and cause great
discomfort, even death. These ‘stones’ or uroliths, (also called calculi, or ‘sand’
when in fine particles/crystals) have various chemical compositions, the most
common being composed of calcium oxalate or of ‘struvite’---a composite of
magnesium, ammonium and phosphate.
Aside from the fact that certain breeds are more
susceptible, there are several co-factors that have also been identified in the
increasing incidence of kidney stones in children. These include not drinking
sufficient fluids (water) which is a major problem when cats are fed only dry
food. Then the urine becomes more concentrated (hypersaturated) which can
trigger bladder inflammation. Bladder inflammation can also be associated with
bacterial infection (notably Staphylococcus and Proteus), especially in female
animals. The bacteria convert urea in the urine into ammonia that inflames the
bladder wall and makes the urine alkaline, creating an ideal environment for
struvite crystals to form often around a core of bacteria or inflammatory material
from the wall of the bladder.
When dogs and cats are fed high cereal diets
becomes abnormally alkaline (it is more acidic on a biologically appropriate
meat-based diet). Such diets are another co-factor in the development of
struvite crystals or calculi. So the best prevention is obvious.
order to avoid
this problem but not reduce the cereal content of their formulas, pet food
manufacturers, who initially blamed high ‘ash’ content of their foods and came
out with low magnesium diets that proved to be of no benefit, now acidify the
Acidification is a co-factor in the development
increasingly prevalent oxalate crystals in cats and dogs. Pets with oxalate
crystals are often given potassium citrate to make the urine more alkaline so
as to help prevent oxalate crystal formation. Adding extra salt to the pet food
to make animals drink more water to control struvite crystal formation actually
encourages the formation of oxalate crystals, a problem seen in children where
the sodium in the salt triggers more calcium excretion by the kidneys. The
excess calcium combines with oxalates present in many foods, to form calcium
oxalate crystals. Soy products (a cheap source of protein used widely by pet
food manufacturers) are high in oxalates and probably represent yet another
co-factor in the genesis of urinary tract blockage and much suffering and
expense to pet owners.
CYSTITIS-THE HOUSE CAT’S
urologic syndrome, that involves inflammation, and possible infection, and
painful mineral crystal and stone formation in the urinary tract, and often the
development of mucous plugs in the urethra, is a widespread problem in cats
is a major
reason why cats are euthanized, or are put outdoors for the day or night
because they become house-soilers, urinating in the home outside of their
litter boxes. The major reason why cats develop this distressing condition is
because they are fed a dry food diet too high in cereals that makes their urine
too alkaline, which encourages the formation of urinary calculi or crystals.
The lack of moisture in the cat’s diet can lead to highly concentrated urine
that is extremely harmful to the lining of the bladder.
include straining to urinate, frequent, often frantic licking of the hind end,
and great difficulty in urinating, blood in the urine, urinary tract
obstruction and inability to urinate at all, (a painful emergency), loud
crying, and voiding at the care-taker’s feet as a clear display of distress.
treatable condition is to be distinguished from cats’ aversion to using the
litter box for such reasons as: it is not being cleaned out daily by the
care-taker; the cat does not like the type of litter; the box is not in a
quiet, low-traffic, easily accessed part of the house; the box is enclosed
under a hood, and the interior becomes ammoniated; the cat has a
pain-associated aversion to using the litter box because of constipation,
impacted or infected anal glands, arthritis, especially spinal, in older cats,
and diseases of the urinary tract.
calculi are involved in the cystitis, it is important to determine what type
they are chemically. With most types, acidifying the urine with Vitamin C or
capsules of cranberry can help. Uva ursi or Bearberry can be a valuable
anti-microbial and anti-inflammatory herbal treatment for cystitis, but it
tends to make the urine alkaline, which is not desirable if a cat has struvite
crystals in the urine. But an overly acidified, artificial diet can lead to
calcium oxalate crystal/urolith formation in the urine, so maintaining an
optimal acid-base balance in the cat’s diet, and normally slightly acidic
urine, is essential. Giving appropriate probiotics
may help when there are oxalate crystals, and in cases of uremia, and
bacterial infection of the urinary bladder and tract.
the cat to drink more water, as by flavoring with milk, tuna juice or
unsalted beef or chicken broth, and not feeding an all-dry type commercial
cat food are additional steps to take. Diuretic herbs like parsley and
dandelion help keep the urinary tract flushed out, but increasing the cat's
fluid intake, as with flavored water and moist, canned or home-prepared foods,
is important. No cereals and more raw or lightly cooked meat to increase the
acidity of the urine is advisable in many cases, unless they have calcium
oxalate crystals in their urine.
and incontinence may have an underlying food allergy and some have made
spontaneous recoveries when all corn was eliminated from their diets---a common
ingredient in many cat foods.
often need antibiotics because of underlying infection. Diabetic cats and those
on long-term steroids, often develop bacterial cystitis because of lowered
immunity. Incontinent cats should be checked for these problems.
type of litter to a non-mineral/clay base, like newspaper or corn pellets, may
stress, as well as an all-dry diet, is a major aspect of feline cystitis/urologic
syndrome. Environmental enrichment, as with perches and climbing posts; a cat
‘condo;’ safe places to hide; identifying and resolving conflict between cats
in the same home; regular play and grooming; providing an extra litter box, and
putting out extra food and water bowls located in a quiet place were cats will
not be startled or compete with each other are all helpful preventive
measures. Treatment with an analgesic like Butorphanol, or with Valium or
Valerian, that have antispasmodic properties as well as being
anxiety-alleviating, has helped many cats during the first 5-10 days of
SIGNIFICANT RESEARCH FINDINGS
RE GENESIS OF STRUVITE CRYSTALS IN CATS
Laboratory of Nutrition, School of Veterinary
Azabu University, 1-17-71 Fuchinobe, Sagamihara 229-8501, Japan.
Urine volume was lower in the starch group and
in study 1, whereas no differences were detected among the groups in study 2.
Urinary pH and struvite activity product were higher in the starch group in
both studies, and the fiber group also had higher struvite activity product in
study 2. In both studies, urinary concentrations of HCl-insoluble sediment were
higher in the starch group and fiber group. In the fiber group, a net loss of
body calcium, phosphorus, and magnesium was detected in study 2.
Starch and fiber in diets potentially stimulate
struvite crystals. Hence, reducing dietary carbohydrate is desirable to prevent
struvite urolith formation. In addition, a net loss of body calcium,
phosphorus, and magnesium during feeding of the fiber diet suggests that
dietary inclusion of insoluble fiber could increase macromineral requirements
Also, these acidifying diets, which are so often
may end up promoting calcium oxalate stones and hypokalemia.
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