Arthritis is a term used to describe joint pain or disease. The two most common types are Osteoarthritis (OA) and Rheumatoid Arthritis (RA). It can be an extremely debilitating condition as the main arthritis symptom is pain. Longstanding pain is associated with considerable loss of quality of life and employment and enormous cognitive, social, and economic costs.
OA is the most common form of arthritis. Symptoms include joint stiffness, pain and dysfunction. At each joint, cartilage covers the ends of the bones to protect them and act as a cushion. In OA there is a loss of cartilage and degeneration of its protective qualities. Thickening of bone underneath the cartilage occurs and new bony spurs are formed at the margins of the bones. As the disease progresses, other tissues around the joint also become affected.
However, there is often poor correlation of clinical symptoms with radiological or imaging appearance. This lack of correlation shows that it is more a complicated issue then just the status of the bones and cartilage. It is generally believed that pain and disability are associated with degeneration of cartilage and bone, as well as with muscle weakness and limitations in joint motion, and with anxiety, coping style, focus on symptoms, and depression.
What causes arthritis is still up for debate. There is a strong association between age and the presence of OA. Genetic factors also play a role. However, its development and progression are likely due to an interaction among multiple genes, in combination with risk factors such as weight and repetitive movements that put strain on the joints.
RA is a complex immune-mediated disease. Signs and symptoms include:
- morning stiffness in and around joints lasting at least one hour
- swelling of the soft tissue around three or more joints
- swelling of the finger or wrist joints
- symmetric pain
- subcutaneous nodules
- a positive test for rheumatoid factor and
- radiographic evidence of erosions or bone thinning
Rheumatoid arthritis usually becomes symptomatic gradually. General fatigue may be present before any joint symptoms, then the fingers and wrists are the first to become symptomatic, while the hips and ankles become affected much later. As with other forms of arthritis, the exact cause is not known but it is accepted that smoking is a major risk factor.
A rarer form of arthritis is psoriatic arthritis (PsA). This is a chronic and inflammatory arthritis that occurs in association with skin psoriasis. The prevalence of psoriasis is about 1-3%, and about 6-42% of patients with psoriasis develop PsA. The disease manifests first in people aged 30-55 years old, which is relatively young compared with other rheumatic diseases. It is associated with impaired physical function, reduced quality of life, and increased mortality.