Arthritis is the term that describes a joint that is inflamed and suffers pain, swelling, heat and redness.  Arthritis can be monoarticular (affecting a single joint), or polyarticular (affecting several joints).  Monoarticular arthritis is commonly due to injury, infection, or gout.  Polyarticular arthritis can be due to osteoarthritis (overuse, injury, age) in which the big joints and neck are most likely affected; or to a systemic disorder (such as Rheumatoid arthritis, drug reaction, hepatitis, Systemic Lupus) wherein smaller joints (fingers, wrists) are most commonly affected.

When examining an arthritic joint your physician may need to put a needle into the joint space in order to obtain a specimen of joint fluid.  An examination of the joint fluid will tell us whether the disorder is due to bleeding into the joint, an infection, or gout.  Of course, X-rays are very helpful in the diagnosis.

If a systemic disease is suspected as the cause, there are several tests that can be useful.  These include the Rheumatoid Arthritis test (RA Test) and the ANA (Antinuclear Antibody) test that helps diagnose Lupus and other autoimmune disorders.