Arthritis is defined as inflammation of a joint.
Joints are the structures that joint two or more bones together.
Osteoarthritis is a variant of arthritis in which the bones of the joint
have become inflamed as well. Joints are created by a strong fibrous
tissue “joint capsule” and ligaments (bands of tissue) that hold the
joint together and limit its range of motion. The inside of joints is
filled with a lubricating “joint fluid” created by the cells lining the
joint (synovial cells). This fluid lubricates and nourishes the
cartilage, which makes up the gliding surfaces of the bones.
Inflammation is a reaction of the body in response to a noxious
stimulus that results in swelling, pain, heat and redness. The noxious
stimulus can be mechanical trauma (overextension, hyper flexion, rupture
of ligaments, straining of ligaments etc), infectious agents (bacteria
and viruses) or immune system related (where the immunes system attacks
the joints in the body as in Rheumatoid arthritis). Inflammation is
caused by various chemicals created by the body that are released into
the joint in response to the stimuli listed above. As scientists
continue to unravel the mechanism by which the inflammatory response is
caused, they have been able to develop new drugs to help combat it.
How do we diagnose Arthritis?
When we are presented with a pet that is exhibiting pain related to a
joint (lameness) we first try to isolate the location of the pain
through a thorough physical examination including palpation of all the
joints on the affected limb. Frequently, this may require mild to heavy
sedation because the painful pet may resist palpation and make it
difficult to isolate the problem. Once we have found the affected area(s),
then we will generally take radiographs (x-rays) of the affected joints.
Most often taking radiographs will require heavy sedation or general
anesthesia. This is due to the fact that the joints must be held very
still in awkward positions to get diagnostic films. Most pets will
resist this positioning due to the pain and thus thwart our ability to
gain a diagnosis.
Radiographs will tell us if there has been any damage to the bones in
the joint such as fractures or chips off of the bone as well as if any
of the bones are misaligned (luxated or sub-luxated). They will help us
determine how long the inflammation has been going on and whether the
bones have been affected by the inflammatory process. Finally, they can
help us determine if there is an infectious or cancerous condition
causing the problem. This information is vital in helping us determine a
treatment strategy and determining the prognosis for recovery.
In many cases, we may need to take a sample of the joint fluid for
analysis to help determine what is causing the arthritis. These samples
are generally obtained by withdrawing joint fluid with a needle while
the pet is anesthetized. The fluid is sent to the laboratory where the
types of cells are analyzed and the fluid is cultured to check for
bacterial agents. If immune mediated arthritis is suspected, a variety
of blood tests may be run to help verify the diagnosis.
How do we treat arthritis?
Treatment of arthritis depends on the cause of arthritis. If there has
been damage to the bones, ligaments or joint capsule, the joint becomes
unstable. As long as the joint is unstable, the inflammation will not
stop. Therefore, we may need to perform surgery to correct the problem
causing the instability. If the problem is caused by an infectious agent
(bacteria, fungus or viral) we will need to treat with an appropriate
antibiotic, anti fungal or antiviral agent. If the arthritis is severe,
we may need to surgically drain the joint and flush it out to help get
rid of the toxins. Drug therapy for infected joints usually lasts 6 to
12 weeks at a minimum. Immune mediated arthritis is treated with a
variety of drugs aimed at suppressing the immune system. These drugs can
have many side effects and the patient must be monitored closely
throughout the therapy.
Regardless of the cause of the arthritis, we usually will add drugs to
the regimen to help relieve the pain and inflammation for the comfort of
the pet. These drugs fall into the categories of non-steroidal
anti-inflammatory drugs (NSAIDS), steroid drugs and chondro-protectants
(cartilage protectors).
NSAIDS include drugs like aspirin, ibuprophen, naproxen and many others.
Most of the drugs used for humans tend to cause severe side effects in
pets (bleeding ulcers and kidney failure) and should never be given
without direct supervision of your veterinarian. Fortunately, in recent
years a number of newer drugs have become available for pets that
minimize the side effects while providing the desired benefits.
Derramaxx is one such drug and has been very successful in our hands.
It, like all drugs has some risks, which will need to be discussed
before prescribing it.
Chondro-protectants are drugs that help to protect the cartilage in the
joint from the effects of inflammation. They also increase the
“slipperiness” of the joint fluid (viscosity) to improve the lubricating
properties in the joint. Adequan is an injectable version of this drug
type. It is generally administered by a series of injections over a
number of weeks to build up the drug levels in the joints. Then, many
pets can be switched to an oral powder (Dasequin) that will be given
daily on the food. These drugs have the least side effects of any of our
anti-arthritis drugs and play an important role in the management of
chronic arthritis.
Steroid drugs are derivatives of cortisone, which is a naturally
occurring hormone in the body. Steroids are the most potent
anti-inflammatory agents available. They can work wonders for an
arthritic pet. Unfortunately, long-term use of steroids may actually
make certain types of arthritis worse. In addition, there are many
systemic side effects from these drugs and so they are not generally
used until other options have been exhausted.
In all cases of arthritis, rest is essential to allow the body to heal.
Generally 2-3 weeks of enforced rest is requires. In, sudden onset
arthritis caused by strain or sprain an external splint may be applied
during this period allow the soft tissues to heal without pressure. In
the same vein, weight control is equally important to reduce the strain
on the affected joint(s). Frequently, we may prescribe strict weight
loss regimens for overweight arthritis sufferers.
Stem Cell Therapy: A cutting edge therapy is now
available for the treatment of chronic arthritis using the patient's own
stem cells to help improve the affected joints.
Click here for more information.
What is the prognosis for arthritis?
The prognosis for arthritis varies with many factors. Sudden onset
arthritis in which no ligaments have been ruptured, no bones have
luxated (as in a sprain or strain) may have a very good prognosis
provided it is treated quickly and appropriately. Infectious and immune
mediated arthritis have variable outcomes and always carry a guarded
prognosis. The longer a lameness goes undiagnosed and untreated, the
worse the prognosis becomes. Once the bone becomes involved the joint
surfaces become roughened and irregular, the prognosis gets
significantly worse. The reason for this is that it is nearly impossible
to reverse those bony changes once they have developed. Most pets that
have arthritis that has involved the bone will require drug therapy for
life. Frequently drugs may lose their effectiveness and various
“salvage” surgical procedures may need to be performed. These include
joint fixation (arthrodesis), joint replacement and other surgical
procedures, which aim to reduce the pain and improve the quality of life
of your pet.
Given this information, you can see how important it is to bring your
pet into the veterinarian for evaluation at the first sign of lameness.
Early intervention may help your pet avoid years of chronic pain and
suffering.
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