Technical information for veterinarians

Arthritis in dogs

Two primary categories of arthritis affect dogs:

  • Degenerative joint disease (DJD)
  • Inflammatory joint disease

DJD is by far the more common condition, affecting one in five adult dogs. The condition may not be noticed by the pet owner until the animal has had years of abnormal stress. Since the cartilage has no nerve supply, the damage can progress with no outward symptoms until the joint is severely damaged and the lubricating fluid has lost its ability to protect the bone surfaces. This is why the degenerative form of arthritis is most often seen in older animals.

Certain breeds of cat and dog have an inherited predisposition to develop primary osteoarthritis (hip dysplasia in the Burmese cat and Labrador-retriever, for example). In general, purebreds have increased tendency for development of arthritic conditions. Secondary osteoarthritis is more common, usually developing after trauma to the joint such as traffic accident, infection in a joint, or abnormal stresses on the joint surfaces.

Types of arthritis in dogs

TRAUMATIC ARTHRITIS

This is a catchall term for the degenerative changes to a joint resulting from one-time or repetitive trauma to the joint.

Acute traumatic arthritis

Acute trauma to a joint may manifest as sudden onset lameness with swelling, heat and pain. It is important to differentiate this type of acute joint pain from other conditions such as infective arthritis. Early assessment and treatment can markedly reduce long-term damage to the joint. With acute traumatic arthritis, there is disruption of the cartilage, bone, synovial membranes and ligaments that support the affected joint. Inflammatory changes lead to increased synovial fluid production with swelling and associated pain.

Disruptive and acute traumatic conditions involving bone damage/dislocation and/or tearing of the ligaments may require surgical intervention. This should only take place after stabilization of the animal and, following this, the joint itself. Several weeks of resting of the joint are normally necessary. Immobilization may also be required, depending on the nature and severity of the trauma. Trauma to the joint/s often leads to osteoarthritis.

Non-disruptive, traumatic acute conditions will not require surgery. Rapid immobilization/rest and the use of NSAIDs will provide good results in many cases although in severe cases osteoarthritis will result.

Repeat trauma-induced arthritis

Repeat trauma-induced arthritis develops when poor conformation is present, or when the animal’s activity gives rise to joint instability. Careful and regular assessment of the growing animal can help limit problems caused by poor conformation. When the animal’s specific activity is the cause, this should be identified and limited/eliminated as soon as possible to prevent severe damage.

INFLAMMATORY ARTHRITIS

This group of diseases is far less common than degenerative arthritis.

Infective Arthritis

Infective arthritis may manifest as either acute lameness or a suddenly sore joint, depending on the nature and source of infection. Early diagnosis and intervention is of prime importance as the condition can lead to severe joint degradation and permanent incapacitation.

Joints may become infected in one of two ways: direct penetration of the joint, as with a road accident, bite or sharp object such as a nail or thorn, or through spread of the organisms responsible via the blood supply.

Organisms responsible for infective arthritis are varied and include B-hemolytic Streptococci, Staphylococci, hemolytic E. coli, Erysipelothrix, and Corynebacterium.

X-rays should be taken (to rule out other causes of joint damage as well as to provide a diagnosis of infective arthritis), and a sterile sample of joint fluid will be required for bacterial culture, antibiotic sensitivity and microscopic examination. Blood tests may also be helpful.

Aggressive treatment with antibiotics specific to the bacterial organism is required in all cases. In severe cases, joint drainage and lavage may be required. Pain and anti-inflammatory relief may be required using NSAIDs. (See Treatment Options.)

Auto Immune Arthritis

Auto immune arthritis normally affects several joints. Severe inflammation of the synovial membranes is present along with swelling, heat and pain in the joints. Immune complexes are produced either locally in the joint or systemically. These immune complexes stimulate a type III hypersensitivity reaction that gives rise to clinical symptoms. The underlying cause for auto immune arthritis is unknown.

Diagnosis usually centres on a joint fluid sample that is negative for bacterial and fungal culture and a joint fluid analysis that reveals a high white blood cell count, especially neutrophils.

Etiology of arthritis in dogs

The etiology of arthritic conditions varies significantly due to the catchall nature of the term “arthritis.”

The most common forms of the disease, degenerative arthritic conditions, are generally the result of mechanical stress or trauma, which may cause cells in the joint to release large amounts of catabolic enzymes and other biochemicals. Normally, these biochemicals play a role in maintaining the natural balance between the reconstruction and breakdown of cartilage and other joint structures; however, if these biochemicals are released in excessive quantities, joint tissue breaks down rapidly.

Symptoms and diagnosis of arthritis in dogs

In the case of single joint lameness, the affected animal will often display a nodding motion of the head or dropping of the hip. Where multiple joints are affected, the signs may not be as obvious, with the animal taking on a slower gait in an attempt to balance out the limbs. A pet may also be slow in rising from a resting position and reluctant to take on activities such as jumping onto a chair or chasing after a toy.

Arthritis is often difficult to diagnose in dogs because they do not show outward signs of pain. A pet with chronic arthritis may be nervous, overly aggressive, lethargic and/or depressed, prompting owners to assume that he or she is merely suffering from advancing age.

Orthopedic Exam:

A thorough orthopedic examination can reveal the presence of joint pain, swelling and tenderness. A careful history may also suggest a specific primary disease process.

Radiography:

X-rays are usually an essential diagnostic tool. Since the majority of degenerative arthritis seen in small pets is secondary to some congenital or acquired event, radiographic diagnosis of this inciting cause is important.

Contrast Studies:

Occasionally, additional views or “stress” views may be necessary to achieve a diagnosis. (Injecting contrast dye into the joint and obtaining a radiograph is seldom necessary.)

Force plate:

Although primarily used as a research tool to assess the degree of lameness and response to various treatment modalities, the force plate can be used in the clinical setting to help evaluate the degree of lameness in dogs. A plate or mat is placed on the floor and the dog is allowed to make numerous passages across the plate. Sensors in the plate are attached to a computer that analyzes the force each step makes on the plate. There are a number of variables that can occur, but force plate analysis can be helpful.

Aspiration of joint fluid:

Aspiration of joint fluid can be helpful in determining if the arthritic process is inflammatory (rheumatoid like) or non-inflammatory (degenerative arthritis).

Treatment options for arthritis – dogs

Early diagnosis and careful management of arthritis are key to successful treatment.

Owners should be encouraged to control their dog ’s weight through prudent diet and exercise, to eliminate excess stress on the joints.

The following pointers regarding lifestyle management may be printed out for the pet owner:

MANAGING YOUR DOG’S ARTHRITIS

While medications may help your pet overcome pain associated with arthritic conditions, it is important that he or she maintain a healthy lifestyle. Leading an active life will ensure your pet’s joints are kept in motion and remain able to work efficiently.

DIETARY MANAGEMENT

Weight control is an important component of any treatment for arthritis. (Excess weight puts more pressure on the joints, impeding healing.) Your veterinarian will recommend a suitable diet for your pet and you should make every effort to stick with it (as tempting as it may be to give your pet more treats to compensate for his/her pain).

EXERCISE MANAGEMENT

Exercise is an important component of healthy living. Exercise helps reduce pain, prevents further joint damage and can help your pet maintain a healthy weight. Disuse of a sore joint will cause the muscles around it to weaken, resulting in pain. Dogs should be taken for a daily walk and kept as mobile as possible.

While it is difficult to impose an exercise regime on a cat, cats that are affected by osteoarthritis will benefit greatly from regular activity. A little exercise taken frequently is recommended, so be prepared to wake up your cat for a stroll about the house from time to time. Avoid letting him/her sleep in one place for hours.

ADEQUATE REST

Some pets and many working animals do not get adequate rest for optimum healing. (Young children, for example, may interrupt pets excessively, impacting their rest.) Your veterinarian will be able to advise you on how much rest your pet requires during the healing period.

Recovery®SA

Recovery®SA with Nutricol®, is a proprietary lifestyle supplement that can enhance your pet’s quality of life.* It may be used on its own or in combination with prescribed medications. See the Oct 2003 review of Recovery®EQ in the prestigious Horse Journal

For more information on helping your pet stay healthy, please see Tips for a Healthier Dog

Medications

Analgesic and Anti-inflammatory medications – Ideally, these should only be used for the short term, when necessary to encourage movement. Commonly used analgesics and anti-inflammatories include acetaminophen and various NSAIDs (non-steroidal, anti-inflammatory drugs).

Acetaminophen

For mild to moderate arthritis in dogs, acetaminophen (Tylenol®, Panadol®, Exdol®, etc.) may relieve pain. Since acetaminophen has no anti-inflammatory properties, it can generally be safely combined with anti-inflammatory medications when recommended by a veterinarian. Acetaminophen is toxic to cats.

NSAIDs

NSAIDs help reduce pain and swelling of the joints and decreases stiffness. When taken at a low dose, NSAIDs reduce pain; when taken at a higher dose, NSAIDs can also reduce inflammation.

NSAIDs do not prevent joint damage and when used over the long-term, may accelerate joint breakdown. Taking more than one NSAID at a time increases the possibility of heartburn and severe side effects such as ulcers and bleeding. (Special buffered ASA is available for dogs.) The commonly used newer sub-class of NSAIDs, the Cox 2 Inhibitors includes (Rimadyl® (carprofen), Metacam® (meloxicam) and Etogesic® (etodolac).

Caution: Vioxx®, a cox-2 inhibitor for use in humans, was just removed from the market place due to lethal side-effects related to heart attack, stroke, rhabdomyolysis and kidney failure due to the mechanism of action. This same mechanism of action is present in all cox-2 inhibitors and it would be wise to take this into consideration.

Extreme caution should be exercised when prescribing NSAIDs for cats, due to their potential toxic effects. Considerable data exists on the benefits/potential hazards associated with use of NSAIDs in cats. Where obvious suffering is occurring and there is no alternative course of treatment, the judicial use of these drugs may be justifiable. NSAIDs can cause GI upsets and should be discontinued if vomiting, diarrhea or loss of appetite occur. NSAIDs are contraindicated when blood disorders, kidney, liver, heart disease or gastro-intestinal ulcerations are present. Drug interactions are known to occur (e.g. with steroids). NSAIDs are sometimes given short term by injection but more normally by the oral route, with food. Ibuprofen is toxic to a dog’s kidneys.

CORTISONE

For painful arthritic conditions, cortisone may be injected directly into the affected joint. An injection can provide almost immediate relief for a tender, swollen and inflamed joint.

VISCO-SUPPLEMENTATION

Visco-supplementation is the process of injecting a gel-like substance into the joint. This substance lubricates the cartilage, reducing pain and improving flexibility. Visco-supplementation decreases friction within the joint, thus reducing pain and allowing greater mobility. This method of treatment requires ongoing injections as benefits are only temporary. Substances used in visco-supplementation include hyaluronic acid, or HA (Legend®, Hylartin® and Synacid®), and polysulfated glycosaminoglycans (PSGAGS) such as Adequan®), which have anti-inflammatory activity and help modulate cartilage and synovial membrane metabolism.

PSGAGs not only provide replacement materials, but protect chondrocytes and inhibit inflammation, particularly when mediated by prostaglandins. Studies have shown resolution of some lesions and (uncontrolled) studies in dogs suggest that in some instances, DJD may be reversed.

Use of this drug (4mg/kg IM twice weekly X 4 weeks or more) is indicated for DJD associated with any joint (including hip dysplasia) and may be used on dogs and cats at the same dose. Initiation of therapy with polysulfated glycoaminoglycans should be as early as possible to derive maximum benefit. Since Adequan® is similar in structure to heparin, coagulation times may be prolonged for about 7 to 8 hours after treatment with high doses. Treatment prior to surgery, particularly when coupled with ASA, is contraindicated.

Small animal health options

Bioflavonoids (plant-based, antioxidant substances with the power to protect plant and animal tissues), have been shown in many scientific studies to help the tissues maintain their youthful structure. Antioxidants from green tea (Camellia sinensis) and grapes (Vitis vinifera) have been shown to have particularly beneficial effects and may be employed preventively or therapeutically to help repair damaged tissues. Nutricol® (available to veterinarians as Recovery®SA, is a proprietary formulation containing both these ingredients.*

RECOVERY®SA

Recovery®SA with Nutricol®, is a proprietary lifestyle supplement that can enhance your pet’s quality of life.* It may be used on its own or in combination with prescribed medications. See the Oct 2003 review of Recovery®EQ in the prestigious Horse Journal