Simple Definitions for Common RA Medical Terms

If you've been diagnosed with rheumatoid arthritis (RA), you might have a lot of questions. You're probably hearing a lot of medical terms for the first time, and it may be tough to keep them all straight.

Here are some simple definitions for common terms that may come up when you talk with health professionals about RA.

Acute Pain: This is pain that comes on quickly. It can be severe, but it usually lasts less than 6 months.

Antibody: This is a protein in your blood that attacks bacteria, viruses, and other things called antigens that might be harmful. Antibodies stay in your system in case the antigens come back. Your doctor may do a blood test to look for antibodies linked to RA.

Arthralgia: This is inflammation or pain that comes from inside a joint. It can be anything from mild soreness to intense pain that makes it hard to move.

Arthropathy: This is the term for any disease of your joints. Doctors may use it instead of "arthritis." Rheumatoid arthritis is considered an inflammatory arthropathy because it makes your joints inflamed.

Autoimmune: Your immune system's job is to defend your body from infections and diseases. It does this by finding and attacking things like germs. When your immune system makes a mistake and starts attacking your own body's organs or tissues, it's called an autoimmune disease. RA is one of these. If you have it, your immune system attacks your body's joints. It causes inflammation and makes the tissue inside your joints thicker. This then leads to pain and swelling.

Biologic: A biologic is a kind of medicine that's made in live cells. It targets specific parts of your immune system where there's inflammation. Several kinds of biologics are used to treat RA. That includes the first one, called etanercept ( Enbrel), that was approved in 1998.

Chronic Pain: This is pain that lasts a long time. Arthritis pain is considered chronic because it doesn't usually go away completely. And it causes damage to your joints over time. RA can cause chronic pain from the inflammation in your joints.

DMARDs: Disease-modifying antirheumatic drugs (DMARDs) are medications used to treat RA. DMARDs block inflammation. And they can help prevent damage to your joint tissue. There are different kinds of DMARDs -- the kind your doctor recommends for you will depend on your situation. DMARDs aren't considered pain medication, but they can help with pain after a few months since they ease inflammation.

Enthesis: This is where a tendon or ligament meets a joint. Tendons attach your muscles to your bones, and ligaments attach two bones together.

Enthesitis/Enthesopathy: Inflammation and pain in an enthesis is known as enthesitis. A disorder that causes pain, swelling, irritation, or damage to these places is called an enthesopathy. Doctors are still researching how this may play a role in RA.

Erythrocyte Sedimentation: Erythrocyte sedimentation rate (ESR) is a type of blood test. Your doctor may want to do one to see if you have inflammation linked to RA. The test looks at how quickly your red blood cells settle into the bottom of a test tube. If they settle quickly, it's a sign that inflammation in your body is causing the red blood cells to clump together. Your doctor won't be able to diagnose RA from an ESR test alone. But the result can provide key information.

Inflammation: This is the way your immune system responds to a change in your environment. It can be caused by an injury or harmful bacteria entering your body. It also can result from a specific kind of disease or condition. It's a sign that your immune system is fighting something it thinks might hurt you. Inflammation can show up as redness, pain, or swelling if it's happening in a specific part of your body. When you have inflammation, extra immune cells are sent to the site of the injury, along with fluid, which causes swelling. In chronic diseases like RA, your immune system attacks its own cells. This causes inflammation in the tissues, and that leads to pain in your joints.

MRI: Magnetic resonance imaging (MRI) uses powerful magnets and radio waves to make detailed pictures of parts of your body. Doctors sometimes use MRIs to see how RA is affecting you.

NSAIDs: Nonsteroidal anti-inflammatory drugs (NSAIDs) are pain medications that can help with inflammation. Some examples are aspirin, ibuprofen (Motrin, Advil), and naproxen (Aleve). Some people take NSAIDs to lower fever or ease pain from injuries. But they can also be used to treat chronic health problems like RA. Your doctor will tell you if you should take an NSAID and whether you need a prescription or an over-the-counter medicine.

Progression: Every person with RA is different. For most people with RA, the disease is progressive. That means the symptoms get worse gradually over time. Certain things can affect how quickly your RA progresses. They include how far along the disease is when you're diagnosed, your age, and how bad your symptoms are.

Rheumatoid Factor: These are antibodies (blood proteins) your immune system makes that can attack your body's healthy tissues. If you have high levels of rheumatoid factor, it could mean you have an autoimmune disease like RA. But sometimes healthy people have rheumatoid factors too. Having them doesn't necessarily mean you have the disease. The test that looks for rheumatoid factors is part of a group of blood tests that can help your doctor know what's going on with you.

Rheumatoid Nodules: These are lumps that can form under your skin if you have RA. They're usually firm lumps near joints such as fingers, knuckles, elbows, or knees that are affected by RA. They can be as small as a pea or as big as a walnut. They sometimes form together in clusters of tiny bumps called micronodules. Doctors don't know what causes them. They usually don't cause severe pain or major health problems. People who've had other RA symptoms for a long time are more likely to have them. There's no specific treatment for the nodules, but tell your doctor if they hurt.

Rheumatology/Rheumatologist: The branch of medicine that deals with conditions that affect your musculoskeletal system, like RA, is called rheumatology. These conditions can cause pain, swelling, stiffness, and odd shapes in your muscles, bones, and joints. A rheumatologist is a doctor trained to diagnose and treat these conditions.

Synovium: This is the thin tissue that lines the inside of your joints. It helps supply nutrients to cartilage, the tissue in your joints, and helps make them move easily. When you have RA, the synovium gets inflamed. This causes a condition called synovitis. Experts think this is one of the reasons you feel pain when you have RA.

Ultrasound: Sometimes called sonography, this uses high-frequency sound waves to make images on a monitor so your doctor can see inside your body. Your doctor might use it to look closely at your joints and tissue if they think or knows you have RA.