Question: What can you tell me about rheumatic disease and arthritis? — V.J., CLEMSON

Answer: A number of different diseases are considered to be rheumatic. Arthritis is one of them. According to the National Arthritis and Musculoskeletal and Skin Disease Information Clearinghouse, “arthritis” means joint inflammation. It involves swelling, redness, heat and pain caused by tissue injury or disease in a joint. Examples of arthritic diseases include osteoarthritis, rheumatoid arthritis, juvenile rheumatoid arthritis, ankylosing spondylitis, gout, infectious arthritis, reactive arthritis, bursitis and tendinitis.

Some rheumatic diseases affect connective tissue, which is the supportive framework of the body and its internal organs. Autoimmune diseases are another category of rheumatic diseases, in which the immune system harms the body’s own tissues. Examples: fibromyalgia; systemic lupus erythematosus and scleroderma.

Osteoarthritis, a degenerative joint disease, is the most common type of arthritis. An estimated 20.7 million adults in the United States are affected. Osteoarthritis primarily affects cartilage, the tissue that cushions the ends of bones within the joint. Osteoarthritis occurs when cartilage begins to wear and break down. Bony spurs (pointy bulges of bone) may form at the edges of the joint.

Osteoarthritis causes joint pain and reduced motion, loss of function and disability. The disability results most often when disease affects the spine and weight-bearing joints such as hips and knees.

Rheumatoid arthritis is an inflammatory disease of the synovium, or joint lining. Symptoms include pain, stiffness, swelling, deformity and loss of joint function. The inflammation most often affects joints of the hands and feet. Rheumatoid arthritis tends to occur equally on both sides of the body. This symmetry helps distinguish it from other types of arthritis.

Ankylosing spondylitis affects the spine. The tendons and ligaments around spinal bones and joints become inflamed, causing stiffness and pain in the lower back.

Gout occurs when needle-like crystals of uric acid are deposited in the connective tissue, joint spaces, or both. Uric acid is a normal by-product of the breakdown of purines, which are present in body tissues and many foods. Normally, uric acid passes through the kidneys into urine and is eliminated. If the blood concentration of uric acid rises above normal, sodium urate crystals may form in tendons, ligaments and cartilage. Inflammation, swelling and pain develop in the affected joint — most commonly, the big toe.

Infectious arthritis can be associated with parvovirus, gonococcus and Lyme disease. Antibiotics relieve the symptoms and cure the disease.

Bursitis involves inflammation of the bursae, or small fluid-filled sacs that help reduce friction between bones and other moving structures in a joint. Injury or infection of the bursae can cause inflammation, pain and tenderness that limit movement.

Tendinitis is inflammation of tendons, or the tough tissue cords that connect muscle to bone. Overuse, injury or other rheumatic conditions can cause tendinitis. Symptoms include pain, tenderness and restricted movement.

Send your health questions to Debbie Jackson, PhD, MN Clemson University, 302 Sikes Hall, Clemson, SC 29634-5155 or email dbj@clemson.edu