Arthritis is a term used to describe a number of painful conditions of the joints and bones. Two of the main types of arthritis are osteoarthritis and rheumatoid arthritis.

Osteoarthritis

Osteoarthritis is the most common form of arthritis. Cartilage (connective tissue) between the bones gradually wastes away (degenerates), and this can lead to painful rubbing of bone on bone in the joints. It may also cause joints to fall out of their natural positions (misalignment). The most frequently affected joints are in the hands, spine, knees and hips.

Rheumatoid arthritis

Also known as inflammatory arthritis, rheumatoid arthritis is a more severe, but less common condition. The body's immune system attacks and destroys the joint, causing pain and swelling. It can lead to reduction of movement, and the breakdown of bone and cartilage.

There are over 200 forms of arthritis. More common forms include:

• ankylosing spondylitis,
• cervical spondylitis,
• fibromyalgia,
• systemic lupus erythematosis (lupus),
• gout,
• psoriatic arthritis, and
• Reiter's syndrome.

Arthritis is often associated with older people, but it can also affect children. About one in 1,000 children develop arthritis. Arthritis in children is often called juvenile idiopathic arthritis (JIA). The three main types of JIA are:

• Oligo-articular JIA - is the most common form of JIA. It affects four or fewer joints in the body, most commonly the knees, ankles and wrists. This type has good recovery rates and the effects are rarely long term. However, there is a risk of developing eye problems, so children should have regular checks with an eye specialist (ophthalmologist).
• Polyarticular JIA (or polyarthritis) - affects five or more joints, and the symptoms are very similar to adult rheumatoid arthritis. It can quickly spread from one joint to another and can develop at any age. It is often accompanied by a rash or fever.
• Systemic onset JIA - begins with symptoms such as fever, rashes, lethargy and enlarged glands, and later develops into swollen and inflamed joints. It can also affect children of any age.