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Arthritis Health Center

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What Is Inflammation?

Inflammation is a process by which the body's white blood cells and substances they produce protect us from infection with foreign organisms, such as bacteria and viruses.

However, in some diseases, like arthritis, the body's defense system -- the immune system -- triggers an inflammatory response when there are no foreign invaders 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:

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?

Symptoms of inflammation include:

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, swelling of the joint lining and, eventually, wearing down of cartilage (cushions at the end of bones).

How Are Inflammatory Diseases Diagnosed?

Inflammatory diseases are diagnosed after careful evaluation of the following:

  • Complete medical history and physical exam with attention to:
    • The pattern of painful joints and whether there is evidence of inflammation
    • Presence of joint stiffness in the morning
    • Evaluation of other symptoms
  • Results of X-rays and blood tests

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