Rheumatic Heart Disease
According to the World Heart Federation, rheumatic heart disease (RHD) is “the most common acquired heart disease in children in many countries of the world, especially in developing countries,” and “is responsible for about 233,000 deaths annually,” (www.world-heart-federation.org). The disease is most commonly acquired by children ages 5 to 15 years. Environmental risk factors include crowding, poor hygiene, under nutrition, and lack of access to health care.
RHD is a chronic, progressive disease that is preventable with antibiotics. It always begins with a pharyngeal group A streptococcus infection, or in other words, strep throat. In some individuals, this type of infection causes an abnormal immune response in the body known as rheumatic fever. After acquiring an infection with the group A streptococci, the body develops antigens to fight off the bacteria. However, the bacteria share a common protein with the body’s normal tissues so the antigens not only attack the infection, but they also attack the individual’s organs and tissues. This results in inflammation of the joints, skin, nervous system and heart.
When rheumatic fever is untreated, it can lead to RHD. RHD begins with inflammation of the heart, including the interior lining of the heart and its valves. The inflammation causes stenosis, or swelling, and eventually erosion, lesions, and scarring of the valve leaflets. All valves (mitral, aortic, tricuspid, and pulmonic) may be affected by RHD, but the mitral valve is the one most frequently affected. Normally, the valves of the heart are soft, and elastic. They open to allow blood flow and close to prevent backflow of blood. But when the mitral valve becomes stiff, it is unable to open and close all the way and blood flow from the left atrium into the left ventricle is impeded. Mitral regurgitation also occurs in which blood is pushed back into the atrium instead of out through the aortic valve and out to the body. Mitral regurgitation causes a systolic murmur to be heard throughout the chest wall.
Many people who have RHD don’t know it until symptoms of heart failure manifest. Over time, as the heart tries harder to pump blood through the dysfunctional valve, the heart muscle thickens and dilates, becoming dysfunctional. People experiencing symptoms of heart failure are usually short of breath and intolerant to physical activity. They may exhibit swelling in their arms, legs, and abdomen.
RHD is treated according to its severity. To prevent the initial strep infection from causing rheumatic fever (primary prevention), oral antibiotics – usually penicillin – are administered for ten days, or a one-time intramuscular injection of penicillin may be used. If rheumatic fever has developed, recurring episodes of rheumatic fevers are likely. To prevent further damage to the heart from secondary infections (secondary prevention), prophylactic antibiotics are administered routinely for many years. For symptomatic or severely progressed rheumatic heard disease, surgical repair or replacement of the affected valve(s) is indicated (tertiary prevention).
RHD is a relative non-issue in developed countries due to proper medical care, but in underdeveloped countries where health care systems are still evolving, the disease is a burden. The condition of strep throat, if left untreated, may initiate an immune response that can damage the heart, leading to acute rheumatic fever and/or rheumatic heart disease. Repeated exposure to the strep virus without proper antibiotic intervention over time can damage the heart valves and impede functionality with a potentially fatal outcome. Samoa records one of the highest rates of RHD in the world, approximately 14% higher than neighboring countries (Carapetis, 2006; WHO, 2006). The exact reason for this is unknown.