How Do Osteoarthritis and Rheumatoid Arthritis Differ?
Osteoarthritis (also referred to as degenerative joint disease or wear-and-tear arthritis) is caused by the breakdown of joint cartilage. Cartilage acts as a cushion between the bones that form a joint. Cartilage loss can cause bone to rub on bone in a joint -- a condition that is very painful. Usually osteoarthritis begins in a single joint.
Rheumatoid arthritis is a chronic, inflammatory type of arthritis. It is also classified as an autoimmune disease (i.e., immune cells attack the body's own healthy tissues). The synovium (lining of the joint) is primarily affected by rheumatoid arthritis, but organs body-wide can be affected as well. Multiple joints are usually involved with rheumatoid arthritis.
What Causes Osteoarthritis and Rheumatoid Arthritis?
Osteoarthritis is mostly a consequence of aging. Water content of cartilage increases while protein composition of cartilage degenerates. Other factors that may increase the risk of developing osteoarthritis include:
- joint injury
- repetitive use or stress of joints
- being overweight
- family history/genetics
With regard to rheumatoid arthritis, researchers have worked for years to find the cause of the abnormal autoimmune response associated with the disease. No single cause has been found. Common theories point to a genetic predisposition and a triggering event.
What Symptoms Point to Osteoarthritis or Rheumatoid Arthritis?
Osteoarthritis primarily affects the joints. The most common symptom associated with osteoarthritis is pain in the affected joint after repetitive use or activity. Morning stiffness lasts a half hour or less. Joint pain is often worse later in the day. The affected joint can also swell, feel warm, and become stiff after prolonged inactivity. Bone spurs, bony enlargements (Heberden's nodes and Bouchard's nodes), and limited range of motion are also characteristics of osteoarthritis.
Rheumatoid arthritis symptoms include:
- joint pain
- joint swelling or effusion
- joint stiffness
- redness and/or warmth near the joint
- restricted range of motion
Morning stiffness lasting more than an hour, involvement of the small bones of the hands and feet, extreme fatigue, rheumatoid nodules, and symmetrical joint involvement (both knees, not just one) are all characteristics of rheumatoid arthritis. There also can be lung, kidney, or cardiac involvement.
How is Osteoarthritis and Rheumatoid Arthritis Diagnosed?
This is where some similarities occur. X-rays of affected joints can show joint damage associated with osteoarthritis or rheumatoid arthritis. Arthrocentesis, joint fluid removal, and joint fluid analysis are possible procedures that can assess osteoarthritis or rheumatoid arthritis. The results differentiate which type of arthritis is involved.
Blood tests cannot definitively diagnose osteoarthritis, but may be used to rule out other conditions, including rheumatoid arthritis. Test results, a physical examination, and the patient's medical history together can help determine a diagnosis.
Laboratory tests which are commonly ordered to help diagnose rheumatoid arthritis include:
How is Osteoarthritis and Rheumatoid Arthritis Treated?
Treatment options for osteoarthritis focus on pain relief and restoring function to the affected joint. Medications are commonly used to treat osteoarthritis. Nonsteroidal anti-inflammatory drugs, analgesics, as well as steroid injections are used to treat pain and inflammation. Physical therapy that focuses on exercises to strengthen and stabilize the joint, support/bracing, heat, rest, and weight reduction are all important to a successful treatment regimen. Alternative treatments are used, such as massage therapy, acupuncture, and more.
The primary treatment for rheumatoid arthritis is medication. There are 5 categories of medication commonly used to treat rheumatoid arthritis:
- Biologics (Enbrel, Remicade, Humira, Rituxan, Orencia)
- DMARDs (disease-modifying anti-rheumatic drugs such as methotrexate)
- Corticosteroids (such as prednisone, hydrocortisone)
- NSAIDs (nonsteroidal anti-inflammatory drugs such as Celebrex and naproxen)
- Analgesics (painkillers)
Along with medication, some forms of alternative/complementary treatment or local steroid injections may help relieve pain for rheumatoid arthritis. For both rheumatoid arthritis and osteoarthritis, the last-resort treatment option is surgery -- arthroscopy, arthrodesis (fusion), and arthroplasty (joint replacement).
The Prevalence of Osteoarthritis and Rheumatoid Arthritis - How Do They Compare?
Osteoarthritis affects over 21 million people in the United States. Osteoarthritis occurs more frequently in males before age 45 and more frequently in females after age 55. All races in the United States appear to be affected equally by osteoarthritis. According to the American College of Rheumatology, 70% of people over the age of 70 have x-ray evidence of osteoarthritis.
Approximately 2.1 million people in the United States have rheumatoid arthritis and about 1 to 2% of the world's population are affected by rheumatoid arthritis. About 75% of rheumatoid arthritis patients are women. Men, women, and even children can develop rheumatoid arthritis, though. Typically, disease onset for rheumatoid arthritis occurs between 30 and 60 years of age.
Osteoarthritis. Disease Center. Arthritis Foundation. Accessed 11/18/2007.
Rheumatoid Arthritis. Disease Center. Arthritis Foundation. Accessed 11/18/2007.