What is arthritis?

Arthritis is a disease of the various tissues inside joints. A joint is the point at which two or more bones meet. Arthritis can occur as a result of acute (short-term) or chronic (long-term) inflammation (irritation and swelling) in a joint and its surrounding soft tissues. It can also occur after trauma to the joint (such as a broken finger) or possibly from genetic (inherited) and environmental causes.

With arthritis, joints continue to worsen as the cartilage wears down. (Cartilage is the smooth “cushioning” tissue that lines joints.) This weardown of cartilage causes changes in the structure that can be seen on X-rays. The surrounding soft tissues may also get weaker. (Soft tissues are the tendons, ligaments, muscles, and synovial membranes that connect, support, or surround the joint.)

Arthritis is frequently, but not always, painful and may result in a reduced range of motion in the joint, joint deformity, and loss of function. Although almost any joint in the body can be affected, the hand and wrist are common locations for many of the common types of arthritis.

Who is affected by arthritis?

Osteoarthritis affects virtually everyone, especially older people. Women are usually affected more than men and often at an earlier age. X-rays reveal joint damage in approximately 60% of adults over age 60, and in 80% to 90% of patients over age 75.

Rheumatoid arthritis affects about 1% of the adult population. Women are three times more likely than men to develop this disease. Though it may strike persons of any age, it typically begins between the ages of 20 and 40.

What are the types and causes of arthritis?

Osteoarthritis (also known as degenerative arthritis) is the most common type of arthritis. It may affect one or more joints anywhere in the body. Osteoarthritis usually occurs later in life and commonly affects the hands and larger weight-bearing joints, such as hips and knees. Osteoarthritis can cause pain and deformity and can limit the range of motion of the joint.

A number of factors are thought to be important in the development of osteoarthritis. Mechanical considerations (for example, joint stability and alignment, or arrangement) affect how forces are distributed across the joint, and therefore have an impact on how long the joint will last. Also, certain substances (biochemical factors) in the cartilage itself are thought to play a role in the eventual abnormal changes of this tissue.

Risk factors for osteoarthritis include age, traumatic injuries (such as a broken wrist), joint infections, and possibly overuse. Some people inherit the tendency to develop osteoarthritis. How this happens is not well understood. These people are usually affected at an earlier age.

Arthritis may also result from inflammatory conditions that can occur anywhere in the body. The most common inflammatory condition is rheumatoid arthritis. Other inflammatory “arthropathies” include lupus, gout, pseudogout, ankylosing spondylitis, and the arthritis related to inflammatory bowel disease or psoriasis.

Rheumatoid arthritis is an inflammatory and presumed autoimmune disease that affects the entire body, especially the joints. (Autoimmune means the body’s immune system attacks its own tissue.) With regards to the joints, rheumatoid arthritis targets the synovium. Synovium is a tissue that lines and nourishes joints and tendons throughout the body. As part of this condition, the synovium grows, causing local damage to bones, joints, and soft tissues.

Rheumatoid arthritis commonly begins in the hands, wrists, ankles, and feet, and often affects the same joints on each side of the body. Eventually many other joints are affected. The cause of rheumatoid arthritis is unknown, though genetic factors are thought to be critical.

What are the symptoms of arthritis?

Not all patients with arthritis will complain of pain, loss of motion, or deformity. The severity of the symptoms is only loosely linked with the severity of the arthritis as seen on X-rays.

Minor joint injuries may aggravate existing joint damage, resulting in arthritic symptoms that the patient has not had before. These symptoms are more likely to be caused by the pre-existing arthritis, and not by the recent, relatively minor traumatic injury.

Symptoms of osteoarthritis and rheumatoid arthritis are in some ways the same. However, rheumatoid arthritis often will cause more long-lasting morning stiffness and lead to more swelling and redness of the joints. This inflammation of the soft tissues surrounding the joints can eventually result in deformities that limit patients’ ability to use their hands. In addition, patients in the early stage of rheumatoid arthritis may have such symptoms as weakness/tiredness, general discomfort, and loss of appetite.

Symptoms of arthritis from any cause can include:

  • Pain that is limited to the joint itself. This is the main symptom. At first, pain will come and go and is made worse when in use (such as when gripping heavy objects). However, pain is relieved with rest. There may be days or weeks without pain, but also periods of constant discomfort. As the disease advances, the pain becomes more constant, even occurring at rest. The pain changes from a dull ache to a sharp pain, which sometimes extends beyond the joint area.
  • Loss of motion in the joint as arthritis progresses. However, sometimes as motion is lost, pain is lessened.
  • Joint motion that is accompanied by grinding, clicking, or cracking as the cartilage continues to wear down.
  • Joints that swell and often become red and tender to the touch. This is a sign of damage to the tissues surrounding the joint and the body’s response to the constant irritation. Deformity occurs as these stabilizing soft tissues are worn away.
  • Weakness that results from joint pain, loss of motion, and joint deformity.

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