Arthritis

Arthritis
There are some 100 different forms of arthritis, rheumatic
diseases, and related conditions. Virtually all of them have
the potential to affect the knees in some way; however, the
following are the most common:
• osteoarthritis. Most people with knee problems have
a form of arthritis called osteoarthritis. In this disease,
the cartilage gradually wears away and changes occur
in the adjacent bone. Osteoarthritis may be caused by
joint injury or being overweight. It is associated with
aging and most typically begins in people age 50 years
or older. A young person who develops osteoarthritis
typically has had an injury to the knee or may have
an inherited form of the disease.
• rheumatoid arthritis. Rheumatoid arthritis, which
generally affects people at a younger age than
osteoarthritis, is an autoimmune disease. This means
it occurs as a result of the immune system attacking
components of the body. In rheumatoid arthritis, the
primary site of the immune system’s attack is the synovium,
the membrane that lines the joint. This attack
causes inflammation of the joint. It can lead to
destruction of the cartilage and bone and, in some
cases, muscles, tendons, and ligaments as well.
• other rheumatic diseases. These include:
– gout – an acute and intensely painful form of
arthritis that occurs when crystals of the bodily
waste product uric acid are deposited in the joints
– lupus – an autoimmune disease characterized by
destructive inflammation of the skin, internal
organs, and other body systems as well as the joints
– ankylosing spondylitis – an inflammatory form of
arthritis that primarily affects the spine, leading to
stiffening and in some cases fusing into a stooped
position
– psoriatic arthritis – a condition in which inflamed
joints produce symptoms of arthritis for patients
who have or will develop psoriasis
– infectious arthritis – a term describing forms of
arthritis that are caused by infectious agents, such
as bacteria or viruses. Prompt medical attention is
essential to treat the infection and minimize damage
to joints, particularly if fever is present.
Symptoms
The symptoms of arthritis are different for the different
forms. For example, people with rheumatoid arthritis, gout,
or other inflammatory conditions may find the knee swollen,
red, and even hot to the touch. Any form of arthritis can
cause the knee to be painful and stiff.
Diagnosis
The doctor may confirm the diagnosis by conducting a careful
history and physical examination. Blood tests may be
helpful for diagnosing rheumatoid arthritis, but other tests
may be needed too. Analyzing fluid from the knee joint, for
example, may be helpful in diagnosing gout. X rays may be
taken to determine loss or damage to cartilage or bone.