Glossary I

Browse the glossary by selecting a letter or by entering an arthritis-related term:

Immune system

The body’s complex biochemical system for defending itself against bacteria, viruses or other foreign invaders. Among the many components of the system are a variety of cells (such as T cells), organs (such as lymph glands) and chemicals (such as histamine and prostaglandins).

Immunosuppressive drugs

Drugs that suppress the immune system. These treatments may help curb the self-directed immune response in diseases such as rheumatoid arthritis and lupus. However, they must be used cautiously because they can also inhibit the normal immune response, leaving people who take them vulnerable to serious infection.


A response to injury or infection that involves a sequence of biochemical reactions. Inflammation can be generalized, causing fatigue, fever and pain or tenderness all over the body. It can also be localized, for example, in joints, where it causes redness, warmth, swelling and pain.

Infectious arthritis

A form of arthritis that occurs when a blood-borne infection settles in a joint or joints.



A doctor who specializes in the diagnosis, prevention of all forms of adult disease. Training for an internist requires four years of medical school, followed by a three-year residency. Internists may choose to take additional subspecialty training in particular fields, such as rheumatology, endocrinology, cardiology or gastroenterology.

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