What Is Inflammation?

Inflammation is the body's natural response to injury. A sequence of complicated, interrelated events work to defend the body, ultimately bringing plasma proteins and phagocytes (white blood cells that engulf and consume foreign material and debris) to the injured area for the purpose of initiating tissue repair.

How It Happens

The sequence of events that occur during an inflammatory response can vary, depending on the type or cause of injury (i.e., bacteria, trauma), the site of the injury, and the state of the body. In a localized infection, for example, the sequence of events can be summarized in 7 steps:

1 - Microbes (bacteria) enter the body.
2 - Small blood vessels become dilated to increase blood flow.
3 - There is an increase in vascular permeability to protein.
4 - Fluid moves into the tissue causing swelling.
5 - Neutrophils (a type of white blood cell) and later monocytes (another type of white blood cell) move from the blood vessels into the tissue.
6 - Microbes are engulfed and destroyed by white cells.
7 - Tissue repair is initiated.

Inflammation and Disease

In some diseases, the inflammatory process can be triggered even when there are no foreign invaders. In autoimmune diseases, the body's normally protective immune system damages its own tissues, as it erroneously recognizes self as foreign, and normal as abnormal. Some types of arthritis are the result of misdirected inflammation.

Inflammation and Arthritis

The term arthritis literally means inflammation. "Arthr" refers to the joint, and "itis" is indicative of inflammation. Some types of arthritis that are associated with inflammation include:

Inflammatory Activity

An excellent explanation of the destructive pathways of rheumatoid arthritis and inflammatory activity can be found in Conquering Rheumatoid Arthritis: The Latest Breakthroughs and Treatments by Thomas F Lee, Ph.D.

When joint inflammation occurs, the increased number of cells and inflammatory substances within the joint cause irritation, cartilage damage, and swelling of the joint lining. Signs of joint inflammation include: redness around the affected joint; warm to the touch; joint pain, joint stiffness and swelling. There can also be loss of joint function.

Organs

Inflammation can also affect organs in autoimmune diseases. Symptoms depend on the particular organ affected.

Inflammation of the heart (myocarditis) can cause shortness of breath or fluid retention.
Inflammation of kidneys (nephritis) may cause kidney failure or high blood pressure.
Inflammation of the large intestine, known as colitis, may cause cramps and diarrhea.