Introduction
Dogs are prone to many different types
of bone problems. This page will focus on the arthritis that tends to
occur in dogs, especially as they age (Geriatric).
Arthritis literally means inflammation of the joint, but the term is
used more generally to describe several different processes. These
include degenerative joint disease (DJD), infectious joint disease,
immune mediated joint disease, and crystal-induced joint diseases. Many
people use the term arthritis synonymously with osteoarthritis (OA), a
complex, slowly progressive, and degenerative arthritis that is
characterized by the gradual development of joint pain, stiffness, and
a decreased range of motion.
OA, the most common form of joint
disease in dogs, is relatively uncommon in cats. It can be seen in dogs
of all ages, but is more commonly associated with older pets. OA is
becoming more prevalent as the longevity of our pets increases.
As we learn more about the subtleties of
feline medicine we realize that many cats get significant problems in
their lower back. This problem, also know as feline hypersethesia
syndrome, causes tremendous discomfort and decreases the quality of
life from many cats.
Please read our discussion of VOM
at the end of this page. It has made a significant change in how we
treat pets with arthritis. This is especially true for cats with
feline hyperesthesia syndrome.
Anatomy
Anormal joint is lined with hyaline
cartilage, which is the covering over the end of the bone. It provides
an almost frictionless surface for the bones to articulate, and also
acts as a shock absorber. Hyaline cartilage is comprised of
chondrocytes, proteoglycans, and collegan.
A normal joint is encased in a fibrous
structure called the joint capsule. The joint capsule helps stabilize
the joint and keeps the cartilage bathed in synovial fluid. Ligaments,
which attach bone to bone, also provide joint stability.
This is what cartilage looks like in
the knee joint. It is glistening because it is very smooth and has a
lubricating layer over it called synovial fluid.
This picture is from an actual surgery
on the knee of a dog with a ruptured anterior cruciate ligament. The
ridge of bone running vertically at the left is arthritis. Compated its
roughened surface to the picture above.
Cause
The cause of this complex and multi
factorial disease can be primary or secondary. Primary OA results from
normal stresses acting on abnormal cartilage. Secondary OA is more
common, and results from abnormal stresses acting on normal cartilage,
such as an unstable joint caused by canine
hip dysplasia , fragmented coronoid process, ununited anconela
process, patellar luxation, or a ruptured cruciate ligament. Some of
the factors that can cause OA include over- exercising, obesity, poor
nutrition, trauma, immune reactions, and genetic predispositions.
The radiograph on the left is from a
normal shoulder joint. The one on the right has an abnormal flap of
cartilage at the arrow. This is know as osteochondritis dissecans, and
is a primary OA.
Damage to cartilage might occur as one
event, or be the culmination of many small events over years. As
swelling occurs and the joint capusle becomes stretched pain occurs.
Your pet will use the joint less because of this pain, leading to
muscle atrophy and the inablity of the surrounding tendons and msucles
to support the joint. As the muscular support of the joint weakens the
joint capsule, ligaments, and cartilage become further stressed and
stretched, leading to even further pain. At this point the body
releases chemicals called inflammatory mediators, which further damage
the cartilage and add to even more swelling. It is obvious that this
rapidly becomes a vicious cycle leading to debilitating pain.
When OA progresses to the point that you
notice your pet in discomfort or pain the damage to the joint might be
irreversible.
Symptoms
Symptoms are related to joint pain and
stiffness. Most owners notice a pet losing its ability to perform
normally, such as a reluctance to jump or climb stairs, or even
limping. Stiffness after rest that diminishes rapidly is a hallmark
sign of OA. Dogs that will not go on extended walks or pant excessively
during a walk could also indicate OA. Symptoms can be worsened by
obesity, too much exercise, and by cold or damp conditions.
It is important to understand the intial
symptoms
might be subtle. Your pet will be experiencing pain or discomfort,
yet it might not show any external signs.
Diagnosis
Signalment
OA is commonly diagnosed in older dogs
and cats. Some breeds are prone to getting it because of the
conformation of their joints.
Dogs like Dachshunds have
abnormally shaped long bones that might predispose them to OA.
History
Most dogs show a reluctance to run or
move about. Some will be reluctant to go up or down stairs, or might
even be limping. As the disease progresses these dogs might be in overt
pain and lose their appetite. Some of these symptoms occur in other
diseases, notably hip dysplasia and intervertebral disk disease. The are treated in
different ways in many cases, so a proper
diagnosis is imperative.
Physical Exam
In many cases there are no
abnormalities detected during a physical exam.Pain or discomfort might
be found by palpating a joint or pushing on the spinal cord. Dogs with
longer standing OA might show atrophy of muscles.
Diagnostic Tests
Radiography is an important diagnostic
test to perform on a dog or cat suspected of having OA. Even though a
radiograph can be normal in a pet that has OA, it is a substantial help
in verifying the diagnosis and determining the degree of involvement.
There are many diseases that can mimic the symptoms of OA, so a
radiograph should be taken on every suspected OA cause to eliminate
these other causes.
This is a normal knee joint
radiographically.
This one has arthritis. The arrows
point to all of the rough edges that are indicative of OA. Compare
these rough edges to the smooth edges on the radiograph above. Also,
the bone has a stronger whitish appearance, another indication of OA.
This dog was originally suspected of
having arthritis based on a history of soreness in the hip area.
Radiographs revealed a different story, as can be seen at the arrow at
the far left of the radiograph. The white circular area in the bone has
the potential to be many things, some of them serious, so a biopsy is
need to know for sure.
A close-up view gives you a better idea of this dog's
problem.
This form of OA is called spondylosis, which is
arthritis of the vertebrae in the spine.
You can learn more about the bones of
the spine by going to our intervertebral disk page.
This dog was sore around its rear
quarters when petted by the owner. This could easily be arthritis, but
as you probably already figured out, something else was amiss.
Did you figure out what is going on?
Those circular white objects towards the top right of the radiograph
are 3 pennies in the rectum! At least its a safe place to store your
money.
A very important differential when
diagnosis OA on a radiograph is a bone tumor. This one is on the femur
(thigh bone).
The other important differential on
radiograph is a bone infection, called osteomyelitis. The fuzzy or
roughened edges at the arrows is the infection.
Treatment
Treatment of OA initially includes
correction of any underlying primary diseases such as surgical
correction of a torn ligament or arthroscopy to remove a cartilage
flap. Once any primary disease has been addressed, the goal of
treatment is to slow the progression of OA and to keep your pet
comfortable. It's important to realize that there is no cure for OA.
Most pets with OA will require some
adjustment in their lifestyle. Weight management is most important,
since obese pets put unnecessary strain on joints, leading to a more
rapid progression of the disease. Excessive exercise that leads to pain
or discomfort should be avoided, but moderate exercise is recommended.
Swimming is an excellent exercise for pets that have OA and aren't
fearful of water. Most pets do best with several short, exercise
periods per day rather than fewer extended periods. Each patient will
have their own unique program of weight management and exercise, and we
can help you individualize one for you and your pet.
Drugs play an important part in the
management of OA, and should be used in combination with lifestyle
adjustments. Many dogs, especially large breeds can be stoic when it
comes to pain. This means that these dogs are feeling pain, but their
outward appearance appears normal. This type of pain is easily
overlooked, and has lead to inadequate pain relief in the past. With
the advent of modern drugs to treat OA there is no longer any excuse
for these dogs to feel pain.
Chondroprotective Agents
These products typically contain
precursors of cartilage and joint fluid synthesis. They are
administered orally or through injections. Much controversy surrounds
the use of chondroprotective (cartilage protecting) agents. Little
clinical research has been done to substantiate the claims that these
products have a positive effect on cartilage matrix synthesis and that
they have an inhibitory effect on the enzymes that break cartilage
down. These medications require up to 6 weeks of use before OA symptoms
are diminished.
We like to use these medications first
since there are negligible side effects and they can be an aid in
preventing further deterioration of the cartilage.
Adequan
Adequan (polysulfated
glycosaminoglycan) is an injectable chondroprotective agent. Adequan
incorporates into joint cartilage and inhibits several enzymes that
break down cartilage. No studies have been done in animals other than
horses and dogs, but it appears to be safe and effective in other
species including cats, rabbits, ferrets, and birds. We use it first
because of its ability to rapidly help a painful pet.
The intramuscular injections are
initially given twice weekly (every 3-4 days) for a month, then given
monthly as needed. adequan seems to be most effective when given in the
early stages of OA, but is beneficial in all stages of the disease.
Side effects of adequan are much less common than with NSAID's. If
adequan works well after several months we will try an oral
chondroprotective agent called Cosequin.
Cosequin
Unlike the injectable adequan,
Cosequin and other oral joint supplements are considered
nutraceuticals, or nutritional supplements, and do not require FDA
approval. Cosequin contains glucosamine and chondroitin sulfate, agents
proven to be effective at supporting and protecting joint cartilage.
Currently, Cosequin is the only veterinary product that contains highly
purified glucosamine hydrochloride and chondroitin sulfate mixed in a
specific ratio clinically proven to decrease the severity of OA.
Cosequin is given orally at an initial loading dose for six weeks, then
decreased to a maintenance dose that must be given continually. The
rare side effect that occurs is usually related to intestinal upset.
There is a Cosequin made especially
for cats that is very effective.
Synovi G3
One of the newer products we have to
treat arthritis has been very effective in in both dogs and cats. In
addition to glucosamine and chondroitin sulfate, it contains Omega-3
fatty acids, antioxidants, Vitamin E, and MSM to name a few.
NSAID'S
The non-steroidal anti-inflammatories
(NSAID'S) are the most commonly used drugs in treating OA in dogs.
NSAID'S work by inhibiting an enzyme in the inflammatory pathway,
thereby providing analgesia (pain relief), antipyrexia (decreased
fever) and reduced tissue swelling.The enzyme that is inhibited is
called cyclooxygenase (abbreviated COX). This enzyme causes an
inflammatory reaction in the joint fluid that surrounds the joint.
These side effects can be minimized by
using the lowest dosage and frequency possible for your pet. Before we
start your pet on NSAID'S we perform an examination and run a baseline
blood sample. Every 6 months we will examine your pet and recheck the
blood to look for any potential side effects. This will make sure
kidney and liver function is adequate.
Using NSAID'S alone is not recommended
since the signs of arthritis are masked, leading to a more active dog
and a quicker progression of disease. NSAID'S, in combination with
chondroprotective agents, provide cartilage building blocks in addition
to pain relief, and may slow the progression of OA.
Many OTC NSAID'S can be used to treat
OA. These products are readily available and relatively inexpensive.
Some of the more commonly used formulations contain aspirin,
acetaminophen, or ibuprofen. Each product has different
anti-inflammatory and antipyretic properties, and each has a different
margin of safety with respect to dosing. It is very important to
consult a veterinarian before using any OTC drug on any pet, since it
is estimated that these drugs accounted for approximately 1/3 of all
fatal animal poisonings. In general, we do not recommend Tylenol or
Ibuprofen in dogs because of the potential for side effects.
All NSAID'S carry a small risk of side
effects, so careful observation of your pet while on one of these
medications is important. If they occur, the most common side effects
are vomiting and diarrhea. There might also be kidney and liver problems, and even bleeding.
Baby aspirin can be used in cats when
administered under a veterinarians supervision. Cats are much more
sensitive to the side effects of NSAID'S and should not be used without
a veterinarian's prescription. Tylenol is never used in cats
because of its toxic effects.
Rimadyl, Zubrin, Metacam, Piroxicam
These are potent NSAID'S approved
for use in dogs. You can learn more about NSAID's by following this
link: Rimadyl
These products selectively inhibit
the cox-2 enzyme and therefore provide a greater inhibition of the
inflammatory pathway with fewer intestinal and kidney side effects.Side
effects are uncommon, although sensitive individuals may experience
mild intestinal upset. Rarely, more serious liver, kidney, and
intestinal side effects have been reported. Labradors are reported to
be more sensitive to Rimadyl than other breeds, so the use of NSAID's
in this breed should be carefully monitored. In Labradors a blood panel
should be checked to ensure proper liver function, and should be
monitored every 6 months while on this medication.
Steroids
Steroids are broken down into 2 main
classes. The first, known as corticosteroids or cortisone (Prednisone, DepoMedrol),
are very potent anti-inflammatory drugs that we use on a daily basis
for many disease processes. They are not our first choice in treating
OA in dogs since they are thought to actually speed the process of
cartilage destruction.
The other type of steroids are called
anabolic steroids (Winstrol, Deca-Durabolin), which have an opposite
effect to corticosteroids. They are potent medications, and are our
last line of defense.
Steroid therapy in dogs is usually
reserved for cases that have become refractory to other treatments. It
is also used in severe end stage OA where a pet is suffering
considerably and quality of life becomes an issue. These pets get
substantial relief from pain when we give one injection of DepoMedrol
with weekly injections of Deca-Duraboliln. They also help increase the
appetite in older pets that have lost muscle mass.
In cats, corticosteroids are much safer to use than
NSAID'S (Metacam can be used in cats) and are frequently used in
conjunction with chondroprotective agents to treat OA. Cats also seem
much less prone than dogs to the side effects of corticosteroids. Like
any medication that is being used long term, monitoring blood
parameters is recommended. Baby aspirin is also used in cats with
arthritis. It must be used only under the direction of your
veterinarian. Cosequin is used effectively in cats, so all cats
with suspected arthritis should be on it.
Veterinary Neuronal Adjustment (VNA or VOM)
An additional treatment modality that
has yielded great success is called VOM.
It is a non-invasive and non-painful way to stimulate the nervous
system to help correct the problem. Through the use of VOM we can
decrease the use of the above medication in almost all cases. By
decreasing the use of these medications we help your pet live a longer
and healthier life, while decreasing you medication costs over the life
of your pet. Click here to learn more about VNA,
Companion Laser Therapy
In
our never ending search for natural ways to treat arthritis we have
added a new dimension to this treatment protocol that does not involve
drugs. Its called Companion Laser. This modality has been used to treat
people in Europe for over 30 years, and has now been FDA approved for
use in the United States.
This treatment modality has been a
huge boon to our geriatric pets with painful arthritis. This works well
with our balanced medical approach- the bodies natural healin
mechanisms with judicious use of just enough medication to take
advantage of the significant benefits of this medication without their
side effects. To learn more about it please click here or on the
picture below.
As a general rule this is how we
approach arthritis
and its progression in the dog. Your doctor will modify this to
customize it
to
your pet and your specific situation.
Early stages- no drugs, just natural healing treatments
Synovi G3
VNA weekly
Companion Laser Moderate stages
(difficulty rising)- addition of NSAID's
Above
treatment
Piroxicam, Rimadyl, Zubrin, Metacam, Deramaxx, or other NSAID
Robaxin
Pepcid AC (to minimize stomach irritation)
Later stages
Above
treatment
Adequan twice weekly for 4 weeks, then monthly
Advanced stages (quality
of life becomes a significant issue)
Above
treament (sometimes we stop NSAID)
Depo Medrol once
Deca Durabolin every 10 days for 4 treatmens, then monthly
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