A rare but potentially life-threatening disease, rheumatic fever is a complication of untreated strep throat caused by bacteria called group A streptococcus. The main symptoms -- fever, muscle aches, swollen and painful joints, and in some cases, a red, lattice-like rash -- typically begin two to four weeks after a bout of strep. In some cases, though, the infection may have been too mild to have been recognized.
The knees, ankles, elbows, and wrists are the joints most likely to become swollen from rheumatic fever. The pain often migrates from one joint to another. However, the greatest danger from the disease is the damage it can do to the heart. In more than half of all cases, rheumatic fever scars the valves of the heart, forcing this vital organ to work harder to pump blood. Over a period of months or even years -- particularly if the disease strikes again -- this damage to the heart can lead to a serious condition known as rheumatic heart disease, which can eventually cause the heart to fail.
To determine the presence of streptococcus bacteria, your doctor will do a throat culture. This uncomfortable but risk-free procedure involves swabbing a sample of throat mucus for lab analysis. It usually takes 24 hours to grow and analyze the culture. Some doctors also use a rapid strep test that can give results in about five minutes, but it isn't as accurate as the culture.
Your doctor will also give you a complete exam, listening to your heart for evidence of heart valve malfunction -- which...
Rheumatic fever can also cause a temporary nervous system disorder once known as St. Vitus' dance, now known as Sydenham's chorea. This is a nervous disorder -- characterized by rapid, jerky, involuntary movements of the body, usually occurring more on one side of the body. People with mild cases of chorea may find it difficult to concentrate or write. More severe cases can cause the muscles of the arms, legs, or face to twitch uncontrollably. It can also be associated with muscle weakness and emotional outbursts.
Because of antibiotics, rheumatic fever is now rare in developed countries. In recent years, though, it has begun to make a comeback in the U.S., particularly among children living in poor, inner-city neighborhoods. The disease tends to strike most often in cool, damp weather during the winter and early spring. In the U.S., it is most common in the northern states.
What Causes Rheumatic Fever?
Rheumatic fever results from an inflammatory reaction to certain group A streptococcusbacteria. The body produces antibodies to fight the bacteria, but instead the antibodies attack a different target: the body's own tissues. The antibodies begin with the joints and often move on to the heart and surrounding tissues. Because only a small fraction (fewer than 0.3%) of people with strep throat ever contract rheumatic fever, medical experts say that other factors, such as a weakened immune system, must also be involved in the development of the disease.