Rheumatic fever is uncommon in the developed world, but still occurs with an incidence of 1-2/1000 in developing countries. Rheumatic fever is due to an abnormal immune response to the Lancefield Group A streptococcus (Streptococcus pyogenes), which results in a pancarditis that may lead to permanent damage to the heart and heart valves. The left sided valves are most commonly affected, the mitral valve more commonly than the aortic valve. Mitral regurgitation is seen initially; mitral stenosis may develop over time. Approximately 8 million children are affected by rheumatic heart disease worldwide. The typical picture is of a child.
