Arthritis is an umbrella term used to describe pain, stiffness and inflammation of the joints. However, there are different kinds of arthritis, including rheumatoid arthritis (RA) and osteoarthritis (OA).
Although RA and OA both affect the joints, they are very different forms of the same broader condition. Rheumatoid arthritis is an autoimmune condition, while osteoarthritis is a degenerative joint disease.
Autoimmune vs. Degenerative Disease
Rheumatoid arthritis is an autoimmune disease, which means your body attacks itself. The target is the synovium, the soft lining around the joints. The immune system sees the synovium as a threat similar to a virus or bacteria and attacks. As a result, fluid accumulates around the joints. The fluid buildup causes pain, stiffness, tenderness and inflammation—symptoms of RA.
Osteoarthritis, the most common form of arthritis, is a degenerative joint disease. People with OA experience a breakdown of the cartilage that cushions the joints. The wearing down of cartilage causes your bones to rub against each other, which accounts for pain and inflammation. Osteoarthritis does not involve the immune system as in the case of RA.
The demographics of who is affected by OA and RA differ in some ways, yet are similar in others. Both types of arthritis are more common in women than men. Both OA and RA are more prevalent in older adults, although arthritis of any kind can strike at any age.
People who are overweight, suffer from joint deformities, diabetes or gout are more likely to develop OA, according to the Mayo Clinic (Mayo, 2011). By contrast, RA tends to run in families and is more likely in adult smokers.
Symptoms: Similarities and Differences
Many of the basic symptoms of RA and OA are the same:
- painful, stiff joints
- limited range of motion
- warmth or tenderness in the affected area
- increased intensity of symptoms first thing in the morning
Each kind of arthritis also has its own set of symptoms that is not shared. RA is a systemic disease. The autoimmune aspect of rheumatic disease affects the entire body, not just the joints. For this reason, early signs of RA can include low-grade fever, muscle aches, and excessive fatigue. People in advanced stages of RA may notice hard lumps underneath the skin near the joints. The lumps, called rheumatoid nodules, can be painful and impede normal movement.
Osteoarthritis sufferers will likely not experience body-wide symptoms. The degenerative nature of OA is limited solely to the joints, not the entire body. You might develop lumps under the skin around the joints, but these protuberances are different from rheumatoid nodules. People with OA tend to develop bone spurs: small pieces of bone adhere to the edges of the affected joints.
Location of Painful Joints
RA begins in the smaller joints of the body. You are likely to have pain, stiffness and tenderness in the finger joints. As RA progresses, symptoms can develop in the larger joints such as the hips, shoulders, and ankles.
Rheumatoid arthritis is a symmetrical disease. You will experience symptoms on both sides of your body at the same time.
OA is not a symmetrical disease. You might have pain in both the left and right knee, for example, but this is not related to the progression or course of the disease. Osteoarthritis, like RA, is common in the hand and fingers. As the disease progresses, OA often affects the spine, hips and knees.
The primary goal for both OA and RA is to reduce pain and inflammation, and to minimize damage to the joints. Your doctor will approach these goals differently, depending on which form of the disease you have. Anti-inflammatory and corticosteroid medications are generally effective for both OA and RA. Disease-modifying drugs are also prescribed to stop the immune system from attacking the joints in those with RA.