Rheumatic fever is a rare complication of an untreated
strep throat or scarlet fever infection. It is most common between five and 15 years, but can occur at any age.
[MayoClinic.com: Rheumatic Fever] [University of Virginia: Rheumatic Fever]
Rheumatic fever occurs when the body produces antibodies to fight off the
bacterial infection, but the antibodies instead attack the body's own cells. The affected cells are those of the
heart, joints,
central nervous system and
skin. The biggest problem is the damage to the heart. As a result, the heart becomes enlarged, inefficient and may
fail.
[MayoClinic.com: Rheumatic Fever] [WebMD: Understanding Rheumatic Fever]