Rheumatoid arthritis, or RA, is a chronic, autoimmune disease that inflames the synovial lining of the joints. The severity of RA varies among patients, but it often leads to deformity and dysfunction of the affected joints. Several other rheumatic inflammatory illnesses can mimic the symptoms of RA. Clinical presentation, laboratory testing, and sets of diagnostic criteria help to differentiate these conditions from RA.
Systemic Lupus Erythematosus
Systemic lupus erythematosus or SLE, is a chronic, autoimmune disease which affects multiple body systems. It can develop very quickly, or it may evolve over a period of months. The joint symptoms of SLE can mimic those of RA, especially when arthritis is the patient's predominate symptom. Both diseases also exhibit the symptoms of fatigue, and low grade fever. However, unlike RA, damage to the joint space and cartilage are absent in SLE. Other manifestations of SLE such as hair loss, skin involvement, kidney disease and specific antibody tests, can help differentiate systemic lupus erythematosus from rheumatoid arthritis.
Ankylosing Spondylitis
Ankylosing spondylitis is an inflammatory arthritis that primarily affects the spine, and hip joints. Some people with the disease experience pain and inflammation in other joints such as the knee, elbow, ankle, or shoulder. Pain that first develops in areas other than the back may cause ankylosing spondylitis to look like rheumatoid arthritis, or some other type of arthritis. Ankylosing spodylitis and RA both share the symptoms of fatigue, low grade fever and anemia. The extensive spinal involvement of ankylosing spondylitis combined with a negative test for a substance called rheumatoid factor differentiates the illness form RA.
Gout
Gout is an inflammatory condition that causes sudden pain and swelling, usually in a single joint. It is caused by high blood levels of uric acid. The affected joint is very sore, and tender to the touch. The big toe is the joint most often affected by gout, but hands, wrists, ankles, toes, knees, and elbows can also become inflamed. The hot, swollen joint can make gout look like RA, especially if a joint other than the big toe is affected. To diagnose gout, joint fluid must be examined for the presence of uric acid crystals, which do not form in rheumatoid arthritis.
