Arthritis and related diseases are major causes of debilitating, life-changing pain for many Americans. A May 2010 report issued by the Centers for Disease Control and Prevention notes that among adults with arthritis, 37.7 percent report that arthritis causes limitations on their activities, 31.2 percent say it leads to work limitation, and 25.6 percent note that it causes severe pain (seven or higher on a zero to 10 point scale).

There are more than 100 different forms of arthritis and related diseases, but the most prevalent types include osteoarthritis (OA), rheumatoid arthritis (RA), fibromyalgia and gout. All of these conditions can cause pain, but they do so differently.

Here’s a quick overview of the types of pain you are likely to experience if you’ve been diagnosed with one of these conditions, as well as look at the drugs most often used to treat both symptoms and the underlying cause.

Osteoarthritis

In osteoarthritis (OA), joint components like cartilage, a rubber-like material that cushions bones as they move around in the joint, or synovial fluid, which lubricates the joint so bones can move more easily, deteriorate due to years of use, injuries and processes within the body.

As these protective substances break down, movement becomes more difficult and painful. In time, bones may rub directly against one another inside the joint, causing severe pain. Inflammation can also result from this constant, painful friction in the joints, so people with OA often take regular doses of nonsteroidal anti-inflammatory drugs (NSAIDs) to reduce the inflammation and ease pain. In addition, many people with OA take analgesics to ease pain, including acetaminophen or, if pain is severe, an analgesic combined with an opioid, such as codeine or hydrocodone.

OA often affects joints like knees, hips, feet, hands and fingers, wrists, neck and the spinal cord. Typically, OA does not affect the same joint on both sides of the body – such as both knees – but this can occur in some people. OA pain levels vary greatly. Pain can range from mild to moderate and be manageable with drugs and regular physical activity. Or it can be so debilitating that any movement or pressure at all on the affected joints becomes nearly impossible. In severe cases, surgery to replace the damaged joint may be the only effective treatment.

Rheumatoid Arthritis

Rheumatoid arthritis (RA) pain is usually caused at first by a severe inflammation in the joints. This inflammation doesn’t result from joint components rubbing together as in OA, but from a malfunction in the body’s immune system.

Normally, the immune system responds to injury or illness by triggering temporary inflammation. This inflammation lets you know that there’s a problem and that you should treat the issue or rest the injured joint. In RA, the immune system goes awry and turns against healthy tissues. The inflammation is chronic rather than temporary.