Introduction to Rheumatic Heart Disease
Rheumatic heart disease (RHD) is a chronic inflammatory condition that affects the heart, primarily resulting from acute rheumatic fever. This disease is particularly significant in regions with limited access to healthcare. It involves the progressive damage to heart valves and other cardiac structures due to an autoimmune response triggered by a throat infection from
Group A Streptococcus.
Histological Features of Rheumatic Heart Disease
Histologically, RHD is characterized by several distinct features. The inflammation primarily affects the
endocardium, including the heart valves, but can also extend to the myocardium and pericardium (pancarditis).
Aschoff Bodies
One of the hallmark histological features of RHD is the presence of
Aschoff bodies. These are granulomatous lesions consisting of central areas of fibrinoid necrosis surrounded by chronic inflammatory cells such as lymphocytes and macrophages. The macrophages often exhibit a characteristic appearance termed Anitschkow cells, which have abundant cytoplasm and caterpillar-like nuclei.
Valve Changes
The heart valves, particularly the mitral and aortic valves, show significant histological changes in RHD. These include
fibrinoid necrosis in the acute phase, followed by fibrous thickening and fusion of the valve leaflets in chronic stages. This results in valvular stenosis or regurgitation, severely impairing cardiac function.
Myocardial Involvement
In addition to valvular damage, the
myocardium may show interstitial fibrosis and scattered Aschoff bodies in cases of myocarditis. This can lead to cardiac arrhythmias and heart failure if left untreated.
Pericardial Involvement
The pericardium may also be involved, showing signs of
fibrinous pericarditis, which can lead to pericardial effusion and potentially constrictive pericarditis if extensive fibrosis occurs.
Clinical Correlation
The histological changes in RHD correlate with clinical symptoms such as heart murmurs, chest pain, and dyspnea. Early diagnosis and treatment of acute rheumatic fever are essential to prevent the progression to RHD. Histopathological examination of biopsy or autopsy samples can confirm the diagnosis.Conclusion
Rheumatic heart disease remains a significant health concern, particularly in developing countries. Histological examination reveals characteristic features such as Aschoff bodies, valve fibrosis, and myocardial involvement. Understanding these histological changes is crucial for diagnosis, management, and prevention of this chronic condition.
