Rheumatoid Arthritis – Pathophysiology
Rheumatoid arthritis is a chronic inflammatory disorder that typically affects the small joints in your hands and feet. Unlike the wear-and-tear damage of osteoarthritis, rheumatoid arthritis affects the lining of your joints, causing a painful swelling that can eventually result in bone erosion and joint deformity.
An autoimmune disorder, rheumatoid arthritis occurs when your immune system mistakenly attacks your own body’s tissues. In addition to causing joint problems, rheumatoid arthritis sometimes can affect other organs of the body — such as the skin, eyes, lungs and blood vessels.
Although rheumatoid arthritis can occur at any age, it usually begins after age 40. The disorder is much more common in women.
Treatment focuses on controlling symptoms and preventing joint damage.
Signs and symptoms of rheumatoid arthritis may include:
- Tender, warm, swollen joints
- Morning stiffness that may last for hours
- Firm bumps of tissue under the skin on your arms (rheumatoid nodules)
- Fatigue, fever and weight loss
Early rheumatoid arthritis tends to affect your smaller joints first — particularly the joints that attach your fingers to your hands and your toes to your feet.
As the disease progresses, symptoms often spread to the wrists, knees, ankles, elbows, hips and shoulders. In most cases, symptoms occur in the same joints on both sides of your body.
Rheumatoid arthritis signs and symptoms may vary in severity and may even come and go. Periods of increased disease activity, called flares, alternate with periods of relative remission — when the swelling and pain fade or disappear. Over time, rheumatoid arthritis can cause joints to deform and shift out of place.
Rheumatoid arthritis occurs when your immune system attacks the synovium — the lining of the membranes that surround your joints.
The resulting inflammation thickens the synovium, which can eventually destroy the cartilage and bone within the joint.
The tendons and ligaments that hold the joint together weaken and stretch. Gradually, the joint loses its shape and alignment.
Doctors don’t know what starts this process, although a genetic component appears likely. While your genes don’t actually cause rheumatoid arthritis, they can make you more susceptible to environmental factors — such as infection with certain viruses and bacteria — that may trigger the disease.
Factors that may increase your risk of rheumatoid arthritis include:
- Sex. Women are more likely to develop rheumatoid arthritis.
- Age. Rheumatoid arthritis can occur at any age, but it most commonly begins between the ages of 40 and 60.
- Family history. If a member of your family has rheumatoid arthritis, you may have an increased risk of the disease.
Rheumatoid arthritis increases your risk of developing:
- Osteoporosis. Rheumatoid arthritis itself, along with some medications used for treating rheumatoid arthritis, can increase your risk of osteoporosis — a condition that weakens your bones and makes them more prone to fracture.
- Carpal tunnel syndrome. If rheumatoid arthritis affects your wrists, the inflammation can compress the nerve that serves most of your hand and fingers.
- Heart problems. Rheumatoid arthritis can increase your risk of hardened and blocked arteries, as well as inflammation of the sac that encloses your heart.
- Lung disease. People with rheumatoid arthritis have an increased risk of inflammation and scarring of the lung tissues, which can lead to progressive shortness of breath.
Tests and diagnosis
Rheumatoid arthritis can be difficult to diagnose in its early stages because the early signs and symptoms mimic those of many other diseases. There is no one blood test or physical finding to confirm the diagnosis.
During the physical exam, your doctor will check your joints for swelling, redness and warmth. He or she will also check your reflexes and muscle strength.
People with rheumatoid arthritis tend to have an elevated erythrocyte sedimentation rate (ESR, or sed rate), which indicates the presence of an inflammatory process in the body. Other common blood tests look for rheumatoid factor and anti-cyclic citrullinate d peptide (anti-CCP) antibodies.
Your doctor may recommend X-rays to help track the progression of rheumatoid arthritis in your joints over time.
Treatments and drugs
There is no cure for rheumatoid arthritis. Medications can reduce inflammation in your joints in order to relieve pain and prevent or slow joint damage.
Occupational and physical therapy can teach you how to protect your joints. If your joints are severely damaged by rheumatoid arthritis, surgery may be necessary.
Many drugs used to treat rheumatoid arthritis have potentially serious side effects. Doctors typically prescribe medications with the fewest side effects first. You may need stronger drugs or a combination of drugs if your disease progresses.
NSAIDs. Nonsteroidal anti-inflammatory drugs (NSAIDs) can relieve pain and reduce inflammation. Over-the-counter NSAIDs include ibuprofen (Advil, Motrin IB) and naproxen sodium (Aleve). Stronger NSAIDs are available by prescription. Side effects may include ringing in your ears, stomach irritation, heart problems, and liver and kidney damage.
Steroids. Corticosteroid medications, such as prednisone, reduce inflammation and pain and slow joint damage. Side effects may include thinning of bones, weight gain and diabetes. Doctors often prescribe a corticosteroid to relieve acute symptoms, with the goal of gradually tapering off the medication.
Disease-modifying antirheumatic drugs (DMARDs). These drugs can slow the progression of rheumatoid arthritis and save the joints and other tissues from permanent damage. Common DMARDs include methotrexate (Trexall), leflunomide (Arava), hydroxychloroquine (Plaquenil) and sulfasalazine (Azulfidine).
Side effects vary but may include liver damage, bone marrow suppression and severe lung infections.
Biologic agents. Also known as biologic response modifiers, this newer class of DMARDs includes abatacept (Orencia), adalimumab (Humira), anakinra (Kineret), certolizumab (Cimzia), etanercept (Enbrel), golimumab (Simponi), infliximab (Remicade), rituximab (Rituxan) and tocilizumab (Actemra). Tofacitinib (Xeljanz), a new, synthetic DMARD, is also available in the U.S.
These drugs can target parts of the immune system that trigger inflammation that causes joint and tissue damage. These types of drugs also increase the risk of infections.
Biologic DMARDs are usually most effective when paired with a nonbiologic DMARD, such as methotrexate.
Your doctor may send you to a therapist who can teach you exercises to help keep your joints flexible. The therapist may also suggest new ways to do daily tasks, which will be easier on your joints. For example, if your fingers are sore, you may want to pick up an object using your forearms.
Assistive devices can make it easier to avoid stressing your painful joints. For instance, a kitchen knife equipped with a saw handle helps protect your finger and wrist joints. Certain tools, such as buttonhooks, can make it easier to get dressed. Catalogs and medical supply stores are good places to look for ideas.
If medications fail to prevent or slow joint damage, you and your doctor may consider surgery to repair damaged joints. Surgery may help restore your ability to use your joint. It can also reduce pain and correct deformities.
Rheumatoid arthritis surgery may involve one or more of the following procedures:
Total joint replacement. During joint replacement surgery, your surgeon removes the damaged parts of your joint and inserts a prosthesis made of metal and plastic.
Tendon repair. Inflammation and joint damage may cause tendons around your joint to loosen or rupture. Your surgeon may be able to repair the tendons around your joint.
Joint fusion. Surgically fusing a joint may be recommended to stabilize or realign a joint and for pain relief when a joint replacement isn’t an option.
Surgery carries a risk of bleeding, infection and pain. Discuss the benefits and risks with your doctor.
Video: Nucleus Medical Media