Arthritis is any inflammation of a joint. The difference is the etiology, or cause of the arthritis. There are several causes of arthritis, some from external origins and some internal or hereditary.
Osteoarthritis
Osteoarthritis is often referred to as "garden-variety" arthritis. This is the result of continued wear and tear of the joints, predominately from aging. Osteoarthritis typically begins as minimal irritation of the joint surfaces from activities of daily life, sports and different occupational hazards such as stooping and climbing. As degeneration progresses, so do symptoms of pain, swelling, warmth and increasing difficulty with mobilization efforts.
As the articular cartilage (the cartilage that coats and covers the ends of the bones making up the joint) degenerates, it becomes more brittle and begins to crack and flake. This causes irregularities to the once-smooth joint surfaces. These irregularities cause increased friction, which stimulates the inflammatory process of redness, swelling and pain.
In more severe forms, bone spurs develop along the outer margins of the joint. This is the body's rather lame attempt to increase the overall size of the joint surface, thus reducing friction.
Osteoarthritis can affect literally any joint but is seen most prominently in the weight-bearing joints of the lower extremities--the hip, knee and ankle.
Septic Arthritis
Septic arthritis occurs when an infection becomes so severe within a joint that the pus formed from the infective processes builds to a level that exerts considerable pressure on the structures of the joint, namely the articular cartilage. Persistent pus under pressure can easily destroy a joint in a short amount of time by robbing it of its nourishment from the synovial fluid and compromising blood supply from pressures exerted. This is especially true in children, whose lack of knowledge and physical reserve can prevent them from complaining about joint pain until it has become quite severe and the infection well entrenched.
Post-Traumatic Arthritis
Arthritis can result from injury to the joint as well. It occurs when an injury is severe enough to involve the joint and its smooth surfaces. Fractures are common culprits in disrupting the normal anatomy of the underlying bone beneath the articular cartilage layer. This creation of irregularity and disruption of articular joint surfaces causes uneven wear within the joint, accelerating the degenerative response. The more severe the involvement of a joint from a fracture, the more damage to the smooth, soft articular cartilage, which sets the table for arthritis to develop.
Post-traumatic arthritis can occur in virtually any joint but is more commonly seen in the hip, knee, spine, shoulder and ankle.
Rheumatoid Arthritis
Rheumatoid arthritis is more a disease than a condition. It's considered an auto-immune disease, in which the body is somehow stimulated to literally attack itself by the development of severe and extremely invasive inflammation of the joint lining called the synovium. This synovitis becomes quite invasive and literally invades the joint cartilage from the outer margins inward, destroying it as it migrates.
Rheumatoid arthritis is frequently treated with what is known as immuno-suppressive drugs; systemic steroids are one such avenue. The downside of this is that, while they help considerably to mitigate the inflammation and its resultant pain, long-term usage can cause a condition known as avascular necrosis, or death of a joint. In these cases, the articular cartilage is destroyed because of loss of blood supply to the bones and other elements of the joint by the very drugs that are intended to help.
Rheumatoid arthritis is hereditary, and there are even some forms of the disease for which there are no external symptoms to aid in diagnosis.
Gouty Arthritis
Gout is another hereditary-influenced type of rheumatic disease that causes arthritis. It manifests itself in the presence of abnormally high concentrations of a substance, uric acid, in the bloodstream. Although uric acid is essential for the processing and metabolism of protein for our bodies, excessive uric acid causes problems especially when it settles out of the bloodstream and into one or more joints. This causes acute, arthritic flare-ups called gouty attacks.
Uric acid deposits in the joint as crystals that adhere to the articular joint cartilage, similar to barnacles on a boat or dock piling. The deposits create considerable inflammation and irritation to the joint and excessive fluid buildup occurs, called effusion.
The friction caused by the roughened surfaces from the crystalline deposits helps to erode the cartilage cells, causing degenerative arthritic changes.
Unless properly treated, repetitive gouty attacks can leave joints, especially the knees, destroyed and in need of replacement procedures.
