Osteoarthritis vs. Rheumatoid Arthritis

Osteoarthritis and rheumatoid arthritis are both chronic joint disorders that cause joint pain.

Osteoarthritis (OA) is a chronic joint disorder featuring degeneration and inflammation of cartilage of one or many joints.

Rheumatoid arthritis (RA) is a chronic autoimmune joint disorder characterized by inflammation of the tissue (synovium) that lines the joints. Chronic inflammation of this tissue can lead to cartilage and bone destruction, as well as deformity of the involved joints. RA, an autoimmune systemic disease, has the potential to cause injury to other organs, including the eyes, lungs, and heart.

OA can be primary (of unknown cause or spontaneous) or secondary (a result of injury or disease).

People can inherit primary OA. It can occur as the protein composition of cartilage degenerates due to biologic processes that lead to cartilage inflammation.

Another disease or condition causes secondary OA. Conditions that can lead to secondary OA included repeated joint trauma, joint surgery, obesity, abnormally designed joints at birth, gout, hemochromatosis, diabetes, and other hormonal disorders.

OA may not cause any symptoms in an involved joint. OA can cause

• joint pain,
• bony joint enlargement,
• joint warmth,
• tenderness, and
• eventual misalignment of involved joints.

OA may affect only a single joint. Because OA is not a systemic disease but a local joint problem, there are no systemic symptoms. As cartilage inflammation irritates adjacent bone, new bone can be stimulated to form resulting in bony out growths or spurs (osteophytes). These are visible with X-ray testing as is cartilage loss.

RA causes

• joint pain,
• joint warmth,
• joint swelling,
• joint stiffness (particularly morning stiffness), and
• joint tenderness, typically involving many joints.

Joints are often involved in a symmetrical fashion, involving both sides of the body. Because RA is a systemic disease, it can lead to fever, fatigue, and can cause injury to other organs, such as the lungs, heart, eyes, etc. Because the inflammation leads to bony destruction and weakens ligaments, RA eventually leads to permanent joint destruction and joint deformity. In RA, X-ray testing can reveal characteristic bone damage called erosion.

Doctors can often clinically diagnose OA (with the history and physical examination). In order to determine the degree of OA, simple X-ray testing can note the amount of cartilage loss of the involved joint(s).

Doctors diagnose RA with a history and physical examination, as well as blood testing. Because RA is a systemic autoimmune disease, it is characterized by abnormally elevated blood tests for inflammation (sed rate or sedimentation rate, C-reactive protein, etc.), as well as abnormal markers specific to rheumatoid arthritis, including the antibody "rheumatoid factor or RF." X-ray testing can document joint damage, erosions, and bone thinning from the inflammation of RA.

For symptomatic OA, doctors commonly recommend over-the-counter pain relievers and sometimes fish oil or glucosamine chondroitin food supplementation. These include acetaminophen (Tylenol) and also anti-inflammatory medications such as the NSAIDs ibuprofen or naproxen in selected situations. There are no specific treatments for OA.

Doctors treat RA aggressively with medications that limit or stop the autoimmune inflammation. While over-the-counter pain relievers are sometimes used to supplement treatment, the basic treatment requires medications that must be monitored for benefit as well as any signs of toxicity. These medications include

• methotrexate,
• hydroxychloroquine (Plaquenil),
• sulfasalazine (Azulfadine),
• etanercept (Enbrel),
• abatacept (Humira),
• infliximab (Remicade), and
• many others.

Both OA and RA can progress, though often slowly. In general, because OA is a process that is localized to the involved joint(s), it carries only the risk of progressive loss of joint function of that affected joint.

RA frequently causes progressive joint damage, destruction, and deformity if not treated. The prognosis of patients with RA depends upon its response to treatment, which can be dramatic, and what organs are affected throughout the body (lungs, heart, eyes, etc.).

OA that is secondary to some degree could be prevented by avoiding joint injury and addressing any underlying disease or condition that could harm the cartilage of joints.

It is currently not possible to prevent RA. Perhaps in the future with genetic risk research this may become possible.