Rheumatic fever is the most common cause of acquired heart disease in the world in children and young adults. It can develop in the setting of untreated Group A Strep (GAS) pharyngitis, typically occurring days to weeks after initial infection. Cardiac involvement is common and can include pericarditis, myocarditis or endocarditis, most commonly affecting the mitral and aortic valves. The effects can be acute and/or chronic. The mitral valve is the dominant valve affected followed by aortic valve, tricuspid valve and finally pulmonic valve. Mitral regurgitation can occur in the setting of valvulitis secondary to annular dilation and chordal elongation. Chronic rheumatic heart disease is the most common cause of mitral stenosis due to a combination of leaflet thickening, fusion of the commissures, cusps and chordal shortening. Aortic regurgitation and/or aortic stenosis often co-occur.
References:
Moss, Arthur J., and Hugh D. Allen. Moss and Adams' Heart Disease in Infants, Children, and Adolescents: Including the Fetus and Young Adult. Philadelphia: Wolters Kluwer Health/Lippincott Williams & Wilkins, 2008. Print.1299-1311
Lai, Wyman W. Echocardiography in Pediatric and Congenital Heart Disease: From Fetus to Adult. Chichester, UK: Wiley-Blackwell, 2009. Print 581-594