Arthritis is a general term that covers 200 specific forms of the condition, ranging from osteoarthritis, which is the most prevalent, to rheumatoid arthritis, juvenile arthritis, ankylosing spondylitis, gout and systemic lupus erythematosis (SLE). To add to the confusion, doctors classify arthritic illnesses as musculoskeletal conditions, which embrace any disease of the bones, joints, and ligaments, connective tissue diseases, back pain, osteoporosis, and soft tissue rheumatism.
Osteoarthritis, the most common form of the disease, affects the articular cartilage. This cartilage is mainly made up of water, and its job is to reduce the friction caused by two bones rubbing together. It's a little like a sponge, and it soaks up synovial fluid, which fills the cavity between and around bone joints, and continually releases and absorbs more of it as you move.
Osteoarthritis dries out the cartilage over time. In the early stages, you can just feel stiffness, and movement may become a little difficult. However, as the disease progresses, the cartilage begins to crack and, in its late stage, bone spurs, called osteophytes, abnormal bone hardening and cysts of fluid-filled pockets in the bone can form. The cartilage can even disappear completely in severe cases, leaving the bone ends exposed.
It is considered the result of "wear and tear", occurring with little or no inflammation. Nearly half of the people aged 65 and above will have the condition, while 31 per cent of those aged between 55 and 64 will be affected. It also strikes after infection or injury, and to people who are overweight. As with rheumatoid arthritis, women are more likely than men to develop osteoarthritis.
The disease is mainly confined to the joints, usually in the hand, but also to the weight-bearing joints like the knees and hips, and also those of the spine.
Rheumatoid arthritis, which causes crippling pain, can affect any age group, although those younger than 35 years are in a very low-risk group. It seems to affect three times as many women as men. Thought to be an auto-immune disease, where the body reacts against itself, it not only affects one or a number of joints-such as those in the fingers, elbows, wrists, ankles or knees-but spreads to other parts of the body. Other symptoms can include tiredness and muscle pain.
Earliest change appears as swelling inside the affected joints. The synovial membrane lining around the joints becomes inflamed, which attracts more joint fluid to ease it. Eventually the joint becomes swollen, stiff and warm because of an increased blood flow. After the inner lining of the joint becomes severely inflamed, it becomes scarred-deforming the underlying bony surfaces and wasting the muscles. This is not an inevitable progression, however; one in 10 patients are thought to recover within two years.
Many people assume that rheumatoid arthritis might be brought on by cold (because of the word "rheumatoid"). The disease is in fact just as common in hot countries, although it may be more severe in damp, cold climates.
Ankylosing spondylitis is the most common type of arthritis to affect young and middle-aged men. This disease affects the point where ligaments and tendons join the bone. Spondylitis means "inflammation of the joints of the spine". Pain most often occurs between the sacrum (the last bone in the spine) and the pelvis. Practitioners find that the classic sufferer has a rigid, painful spine and difficulty holding up the head when walking.
Another warning sign of the disease is the development of iritis, an inflammation of the iris of the eye, along with bad back pain.
Gout, or crystal arthritis, is another variation of the disease, which affects 15 times more middle-aged men than women. Many link this form of arthritis with over-eating and over-drinking, although practitioners have found that a particular food allergy can trigger the disease. Diuretic drugs, often prescribed for heart conditions, can also cause the disease.
Pain and swelling occur when minute crystals form in the joint space. The crystals are caused by excess uric acid in the body. Patients receive their first warning signal when they experience an arthritic attack in one of their big toes. The joint becomes tender and painful. However, gout can actually occur in any joint.
Systemic lupus erythematosus (SLE) usually hits young women, and can affect any joint. It is thought to be genetic or caused by drugs and sunlight. Some believe it to be an auto-immune condition, although it's not a view shared by everyone. A red rash over the nose and cheek is a warning sign.
Polymyalgia rheumatica is mostly a muscle disorder, but can affect the joints of people over 50 years old. It affects the hips and shoulders and causes tenderness and distinct muscle pain.