Arthritis is a general term used to indicate any disease that causes pain, stiffness, swelling, and/or inflammation of a joint. It is not one disease but a group of more than 100 diseases whose common threads cause limited movement of the joints. All have varying causes, courses, and cures. There are other diseases that attack the joints causing arthritis-like symptoms, but are not true forms of arthritis.
Arthritis literally means “bone/joint inflammation;” but it is joint pain, rather than inflammation, that is the most important characteristic. However, despite pain being a major symptom, some people with severe osteoarthritis have little or no pain. Therefore, arthrosis may be the more accurate term.
Arthritis, also referred to as degenerative joint disease, is catagorized into inflammatory and non-inflammatory joint diseases. Osteoarthritis (OA) is the most common form of the non-inflammatory arthritic diseases, while rheumatoid arthritis (RA), an autoimmune disorder, is the most common inflammatory form. The focal point of OA is the cartilage, while RA affects connective tissue. Inflammatory joint disease is characterized by damage or destruction in the synovial membrane, articular cartilage, and by systemic signs of inflammation (fever, leukocytosis, malaise, anorexia, hyperfibrogenemia), and can be infectious or non-infectious.
Infectious inflammatory joint disease is caused by an invasion of the joint by bacteria, mycoplasmas, viruses, fungi, or protozoa. These invaders gain entrance via a traumatic wound, surgical incision, contaminated needle, or they can be delivered by the bloodstream through sites of infection elsewhere in the body, typically bones, heart valves, or blood vessels.
The non-infectious type is the most common and results from immune reactions or the deposition of crystals of monosodium urate in and around the joint. Rheumatoid arthritis (RA) and ankylosing spondylitis are non-infectious inflammatory diseases caused by immune reactions. Gout is a non-infectious inflammatory disease caused by crystal deposition. There are numerous other forms of the disease that are dealt with separately, and many are listed under Classifications of Arthritis and Rheumatism.
Until fairly recently, arthritis was thought of as a sign of aging. Today, we know that it can affect any one at any age.
- In the UK, about 20 million people suffer from the disease. Osteoarthritis accounts for about five million while about one million suffer from rheumatoid arthritis. Some 15,000 children are affected, with more girls (86%) than boys suffering from a juvenile form of the disease.
- In the US, one in seven is affected with the arthritis, with estimates ranging between 40 and 60 million people. Of this total, 23 million are women. About 16 million are affected with osteoarthritis and over two million with rheumatoid arthritis. Interestingly, an arthritis-type disease, fibromyalgia, affects more people than does rheumatoid arthritis (3.7 million).
- In Canada, four million people suffer from arthritis, about one in seven like the US.
- In other countries, where similar statistics are available, the proportions are proving to be about the same.
Some of the other diseases that affect the joints include fibromyalgia, Paget’s disease, polymyalgia rheumatica (PMR), polymyositis and dermatomyositis, scleroderma, Sjögren’s syndrome, systemic lupus erythematosus (SLE), and temporal arteritis (TA). There are also a number of rheumatic syndromes associated with HIV infection.