Arthritis, Definition And Description

The following article is an abstract of seminars doctor Smith has conducted since 1996.

Arthritis is the word that is generally used to describe an inflammation of a joint. Many different words are used to describe the different forms of arthritis. 

Traumatic Arthritis: This is a result of a trauma such as sprain, contusion, ruptured ligament, or even a dislocation or fracture.

Septic Arthritis: This is the result of an open wound after a fight or trauma, or the result of an infection spread by the bloodstream. May be the result of an autoimmune disease such as Lupus or rheumatoid arthritis.

Degenerative Arthritis: This can be a result of one of the above conditions after progression, joint instability, or anatomical misalignment.

Osteoarthritis: This term is normally used when the bone has produced extra bone around the joint, creating a larger joint and an irregular joint surface.

Most joint disease will end up in the last two categories if left untreated. Once they are degenerative or osteoarthritis, they will become much more difficult to treat and anatomical changes may inhibit the normal use of the joint. An example of traumatic injuries to the joint is seen in young active dogs especially in those with a tendency for hip dysphasia. The knees endure a lot of twisting and stress, which can result in a rupture of the anterior crusiate ligament. This will result in joint instability leading to inflammation and arthritis. The knee cartilage (or meniscus) can also get damaged in the process.

Joint ligaments can also rupture as a result of the weakening of these ligaments. This can happen in immune disease (immune mediated arthritis) or collagen deficiency. Cause of the last disease is unknown, hereditary factor +/- dietary factor could play a role here.

A similar process can happen in the hip. The hipbone (femur) is kept in place by a ligament called the Ligamentum Teres. This can also rupture as a result of trauma (H.B.C., fall, etc.), spontaneously in rough play (weakening of the ligament) or abnormal strain as a result of abnormal positioning. As a result the hip will dislocate. In the case of the hip, the hip will be painful on palpation and manipulation; a clicking sound in the hip can sometimes be heard.

Diagnoses and differentiation between hip and or knee problem is made with X-rays and palpation under sedation or general anesthetic. Examples of the symptoms are a sudden onset of the hind leg lameness. Often the dog will lift the affected hind leg intermittently while standing. Partial ruptures will create a limping while complete ruptures will often lead to no weight bearing. The knee or hip can be painful on palpation. 

Degeneration or incomplete maturation of the joint cartilage can lead to osteochondritis desiccants (O.C.D.). A small piece of cartilage can become loose in the joint and cause irritation, which leads to inflammation. This can happen in the shoulder joint or hock joint.

In the elbow joint, we know two other conditions, which may lead to arthritis: ununited anconeal process in the German Shepherd dog, and elbow dysplasia. Both of these conditions happen predominantly in large breeds of dogs. In the first one, the anconeal process fails to mature and the joint between bone and cartilage breaks resulting in instability and arthritis.

Symptoms: The sudden onset of a front leg lameness, sometimes holding the leg forward. The elbow is painful on palpation. This condition is seen in young fast growing dogs 6 to 12 months of age. Signs are limping with exercise.

Elbow Dysplacia can be a result of a fracture of the medial coronoid process, leading to instability, inflammation, pain and arthritis. Also the growth plate of the radius might close before the growth plate in the ulna closes. This will result in unevenness in the joint plateau leading to rubbing, inflammation, instability, pain and arthritis.

Septic arthritis: It is understandable that an open joint can get infected. It is more difficult to understand that a general infection can also cause arthritis. In a generalized infection, bacteria can get into the bloodstream and via the blood end up in the joint. The streptococcus bacteria are a classic example. One or more joints are swollen and hot and painful on palpation. The animal can show general illness and fever.

Immune mediated arthritis is often misdiagnosed or missed altogether. Often, more than one joint is affected and in animals, there seems to be a preference for the larger joints. In people, the smaller joints of the fingers and toes and sometime the wrists or elbow are affected. In dogs and cats, the hips, shoulders and elbows are preferred places, but the smaller joints can also be affected. Both in humans and animals, the neck and spine are also often affected. The attacks of inflammation are often periodic—every two or three weeks or months. Stress, weather changes and immune system stimulation (i.e. vaccination or fighting of a flu) often initiate an attack. In between attacks, the animal may seem okay. Repeated inflammations will eventually lead to degenerative or deformative osteoarthritis. During an attack, the animal may show general malaise such as irritability, anorexia, fever, vomiting or diarrhea. Muscles can also be affected and this can lead to atrophy or hypertrophy of the affected muscles. In the case of Lupus, other organs can also be affected such as the skin, liver, spleen or kidney. The origin of immune mediated diseases, when the body attacks its own tissue, is not clearly understood. A hereditary component is suspected, but viruses or bacteria or environmental toxins could also play a role. The disease is difficult to diagnose. An increase in blood globulin and reoccurring attacks are suspicious for the disease.

Degenerative arthritis can be a result of an immune mediated process. Under nourishment of the cartilage of the joint or the intervertebral disc can lead to degeneration and loss of the cushion effect. Also, abnormal anatomical structure can result in a degenerative process. Hip dysplasia will lead to degenerative arthritis followed by osteoarthritis. Hypo or hyper mobility of a joint can also lead to arthritis.

Osteoarthritis: In osteoarthritis we see extra bone formation around the joint. The reason for this is possibly an attempt by the body to neutralize the acidic effect of histamine and other inflammatory agents or to stabilize an unstable joint. This is the picture we can see dramatically on x-rays. The amount of calcium formation around the bone is not necessarily equivalent to the severity of pain or discomfort experienced by the patient. Acute inflammation of the joint gives a sharp stabbing pain while chronic osteoarthritis might create nothing more than a dull pain and stiffness.

Spondylosis is arthritis of the spinal column. The cause can be immune mediated or mechanical trauma such as carrying (heavy) bags, back twisting, jumping, etc. Hypo or hyper mobility, disc herniation, surgery, etc.

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