What causes arthritis?
In order to better understand what is going on when a person suffers from some form of arthritis, let us look at how a joint works.
Diagram of a Joint
Basically, a joint is where one bone moves on another bone. Ligaments hold the two bones together. The ligaments are like elastic bands, while they keep the bones in place your muscles relax or contract to make the joint move.
Cartilage covers the bone surface to stop the two bones from rubbing directly against each other. The covering of cartilage allows the joint to work smoothly and painlessly.
A capsule surrounds the joint. The space within the joint - the joint cavity - has synovial fluid. Synovial fluid nourishes the joint and the cartilage. The synovial fluid is produced by the synovium (synovial membrane) which lines the joint cavity.
If you have arthritis something goes wrong with the joint(s). What goes wrong depends on what type of arthritis you have. It could be that the cartilage is wearing away, a lack of fluid, autoimmunity (your body attacking itself), infection, or a combination of many factors.Arthritis is caused by a combination of several factors working together.
The following factors may contribute towards a higher arthritis risk:
Your genetic makeup.
A physically demanding job, especially one with repetitive movements.
A previous injury.
Some infections or allergic reactions may cause short-term arthritis. When it is caused by an infection it is known as "reactive arthritis".
For a number of people certain foods can either bring on arthritis symptoms, or make existing ones worse.
Obesity, which places extra strain on joints.
Arthritis may also be caused by autoimmune disease.
What Is Inflammation?
When you think of arthritis, you think of inflammation. Inflammation is a process in which the body's white blood cells and immune proteins help protect us from infection and foreign substances such as bacteria and viruses.
In some diseases, however, the body's defense system (immune system) triggers an inflammatory response when there are no foreign substances to fight off. In these diseases, called autoimmune diseases, the body's normally protective immune system causes damage to its own tissues. The body responds as if normal tissues are infected or somehow abnormal.
Some, but not all types of arthritis, are the result of misdirected inflammation. Arthritis is a general term that describes inflammation in joints. The most common form of arthritis called osteoarthritis (also known as degenerative arthritis) is a bit of a misnomer. It is not believed that inflammation plays a major role in osteoarthritis. Other painful conditions of the joints and musculoskeletal system that are not associated with inflammation include fibromyalgia, muscular low back pain, and muscular neck pain.
The symptoms of inflammation include:
Loss of joint function
Often, only a few of these symptoms are present.
What Causes the Symptoms of Inflammation?
When inflammation occurs, chemicals from the body are released into the blood or affected tissues. This release of chemicals increases the blood flow to the area of injury or infection and may result in redness and warmth. Some of the chemicals cause a leak of fluid into the tissues, resulting in swelling. This process may stimulate nerves and cause pain.
What Are the Results of Joint Inflammation?
Increased blood flow and release of these chemicals attract white blood cells to the sites of inflammation. The increased number of cells and inflammatory substances within the joint can cause irritation, wearing down of cartilage (cushions at the end of bones), and swelling of the joint lining (synovium).