Understanding Arthritis: What Is Inflammation?

Inflammation is a process by which the body's white blood cells and chemicals protect our bodies from infection by foreign substances, such as bacteria and viruses.

In some diseases, however, the body's defense system - the immune system - triggers an inflammatory response when there are no foreign substances to fight off. In these diseases, called autoimmune diseases, the body's normally protective immune system causes damage to its own tissues. The body responds as if normal tissues are infected or somehow abnormal.

What diseases are associated with inflammation?

Some, but not all, types of arthritis are the result of misdirected inflammation. Arthritis is a general term that describes inflammation in the joints. Some types of arthritis associated with inflammation include the following:

• Rheumatoid arthritis
• Shoulder tendinitis or bursitis
• Gouty arthritis
• Polymyalgia rheumatica

Other painful conditions of the joints and musculoskeletal system that may not be associated with inflammation include osteoarthritis, fibromyalgia, muscular low back pain and muscular neck pain.

What are the symptoms of inflammation?

Inflammation is characterized by:

• Redness
• Swollen joint that's warm to the touch
• Joint pain
• Joint stiffness
• Loss of joint function

Often, only a few of these symptoms are present.

Inflammation may also be associated with general "flu-like" symptoms including:

• Fever
• Chills
• Fatigue/loss of energy
• headaches
• Loss of appetite
• Muscle stiffness

What causes inflammation and what are its effects?

When inflammation occurs, chemicals from the body's white blood cells are released into the blood or affected tissues to protect your body from foreign substances. This release of chemicals increases the blood flow to the area of injury or infection, and may result in redness and warmth. Some of the chemicals cause a leak of fluid into the tissues, resulting in swelling. This protective process may stimulate nerves and cause pain.

The increased number of cells and inflammatory substances within the joint cause irritation, wearing down of cartilage (cushions at the end of bones) and swelling of the joint lining.

Inflamed joint

How are inflammatory diseases diagnosed?

Inflammatory diseases are diagnosed after careful evaluation of the following:

• Complete medical history and physical exam
• The location of painful joints
• Presence of joint stiffness in the morning
• Evaluation of other symptoms
• Results of X-rays and other tests

Can inflammation affect internal organs?

Yes. Inflammation can affect organs as part of an autoimmune disorder. The type of symptoms depend on which organs are affected. For example:

• Inflammation of the heart (myocarditis) may cause shortness of breath or fluid retention.
• Inflammation of the small tubes that transport air to the lungs may cause an asthma attack.
• Inflammation of the kidneys (nephritis) may cause high blood pressure or kidney failure.
• Inflammation of the large intestine (colitis) may cause cramps and diarrhea.

Pain may not be a primary symptom of an inflammatory disease, since many organs do not have many pain-sensitive nerves. Treatment of organ inflammation is directed at the cause of inflammation whenever possible.