About arthritis

Athritis; from the Greek “anthro” for joint, and “It-is” for inflammation. The bones are covered in articular cartilage; the synovial membranes, which join the surfaces together, and the synovial fluid which provides the lubrication and a lot of the nutrients for the joints. Peripheral to these structures are the ligaments, tendons and muscles which support and mobilise the joints.

The disease can be subdivided into two principal categories,

·         Degenerative.

·         Inflammatory.

OSTEOARTHRITIS

This is a non-inflammatory, often inherent condition of movable joints that result in changes to the cartilage surfaces and their surrounding tissues with cartilage erosion and new depositions of bone to develop changed and irregular surfaces leading to joint pain, stiffness, swelling and limitation in movement with deterioration with age.

How does it occur?

There is little doubt that certain breeds have an inherited predisposition. This is known as primary osteoarthritis and conditions such as hip dysplasia in the labrador-retriever would be a good example. Arthritis occurs through the degradation of the cartilage that partitions two intersecting bones, in the joint. This can be due to “ware and tear” or commonly, it can be caused by an abnormality in the animal’s autoimmune system.

How do you diagnose it?

If a single joint has been damaged lameness is shown by the dog with a nodding action of the head or the ’dropping of a hip’. Where multiple joints are involved, as is often the case, signs may be less obvious as the dog takes on a compensatory gait, balancing out the limbs with slower movement, reduced propulsion and a less active state. A classic example is a dog with hip arthritis to show reluctance to jump into the car. Onset may be acute but more often is slow and subtle with owners believing that their pet is ‘just getting old’. If your dog has started to slow up recently, it probably has arthritis. Dogs rarely show acute pain (they rarely cry out) but increased nervousness, aggression and depression may all be related to chronic pain.

Your vet will help to diagnose the condition and also eliminate other causes of joint disease. Radiographs may be necessary as may analysis of joint fluid (the latter to largely eliminate other reasons for joint damage).

If you own a breed of dog, that has a high risk of arthritis; make sure you have your pet checked by a vet regularly, and ensure that they have a diet rich in fatty acids.

TRAUMATIC ARTHRITIS

This is a generalised term for changes to a joint resulting from either a single or repetitive trauma to that joint. Examples being a road traffic accident, a torn cruciate ligament in the knee or for repetitive trauma, a dog that over extends his back when running resulting in spinal arthritis.

Acute traumatic arthritis

·         Acute trauma to a joint may manifest as a sudden onset lameness with swelling, heat and pain and warrants early veterinary attention . It is important to differentiate this type of acute joint pain from other conditions such as septic or infected arthritis. Early assessment and treatment can reduce the long term damage to the joint. In this condition there is disruption of the cartilage, bone, synovial membranes and ligaments supporting the joint. Inflammatory changes lead to increased synovial (joint) fluid production with swelling and associated discomfort.

·         Disruptive, traumatic, acute, conditions with bone damage, dislocation and ligamental rupture may require surgical intervention but only after stabilisation of firstly the patient and secondly the joint itself. Several weeks of resting of the joint is important with possible immobilisation, depending on the condition may be necessary, including and followed by use of non-steroidal anti-inflammatory and pain killing drugs (NSAIDs). Prognosis has to be guarded in many conditions and a degree of osteoathritis will develop in many cases.

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

·         Repeat trauma induced arthritis occurs when A. there is poor conformation or B. the activity of the animal lends to this occurring. In the former case it is often difficult to deal with although careful and regular assessment of the growing animal can limit problems in this area. In the latter case, identifying the causative action before severe damage is caused and eliminating it will help.

Rheumatoid arthritis

Any breed, usually adult dogs are affected with single or multi-joint lameness varying from stiffness to acute pain. Occasionally fever, lethargy and inappetance accompany the joint disease which may have a symmetric appearance. The joints are swollen and painful with manipulation. Damage and erosion of the cartilage and bone surface occurs with changes to the synovial membranes. The test for Rheumatoid arthritis is a blood test for auto-antibodies known as ‘rheumatoid factor’. There are several ways to test for the condition such as ELISA, radioimmunoassay and the Rose-Waaler test. These tests are not always accurate. Treatment is varied. NSAIDs are effective in mild cases. Severe cases may require immunosuppression with steroids and other cytotoxic agents. Gold injections have proven quite effective.

Systemic Lupus Erythematosus

As the name suggests this condition affects the whole body and can take on many different manifestations. This article will only touch on this condition but can be associated with autoimmune haemolytic anaemia, kidney disease, skin and gum eruptions, central nervous system disease, other blood disorders as well as polyarthritis (multiple joint disease). Again, the causative agents are unknown but there is evidence of an unknown, underlying viral infection which stimulates an abnormal ‘whole body’ response with immune complex hypersensitivity developing against a wide range of body cells and tissues. Clinically the polyarthritic form shows as a symmetrical multi-joint lameness usually with temperature rise, lymph node enlargement loss of appetite, mobility and muscle pain and wastage. Radiographs show little evidence of bone change. Blood testing for antinuclear antibodies (ANA test) if positive with clinical symptoms is a useful indicator of disease. Prognosis with treatment is always guarded, the disease usually being progressive leading to organ failure. Corticosteroids in combination with other cytotoxic drugs such as azothiaprim and cyclophosphamide are often used.

Polyarthritis/Polymyositis syndrome

Often seen in spaniels, showing stiffness and poor exercise tolerance with a crouched posture. The joints may be swollen and painful but a principal feature is contracture and atrophy of muscles leading to shortening of joint movement. This may include the angle of the jaw making eating difficult. Temperature rise and pain are evident. Treatment is as for the other immune based arthritides and prognosis is poor.

Polyarthritis/Meningitis syndrome 

Boxers, Weimaraners, Pointers, Akitas and Bernese Mountain dogs have all been diagnosed with this condition that show as stiffness, temperature rise, painful necks, symmetrical arthritis and sometimes nervous signs. Tests for other immune based arthritides are negative but fluid drawn from the spine show marked inflammatory (but not infected) changes. Corticosteroid treatment can be effective.

Drug Induced Arthritis

Polyarthritis, lymph node enlargement, inflammation of blood vessels leading to skin rashes have been reported after the use of several antibiotics such as the sulpha drugs, cephalosporins, macrolides, and penicillins. Withdrawal of the drugs usually leads to reversion to normal health. There have been reports of polyarthritis after vaccination usually clearing within a few days of the reaction. It must be emphasised that these reactions are rare and are far outweighed by the benefits of treatment or vaccination for the majority.