Rheumatic Fever
🟢Group A streptococcal (GAS) pharyngitis is the etiologic precursor of acute rheumatic fever, but host and environmental factors are important. GAS M proteins share epitopes (antigenic-determinant sites that are recognized by antibodies) with proteins found in synovium, heart muscle, and heart valve, suggesting that molecular mimicry by GAS antigens from rheumatogenic strains contributes to the arthritis, carditis, and valvular damage 🟢Cardiac involvement manifests as carditis, typically affecting the heart from the inside out, ie, valves and endocardium, then myocardium, and finally pericardium. It is sometimes followed years to decades later by chronic rheumatic heart disease, primarily manifested by valvular stenosis, but also sometimes by regurgitation, arrhythmias, and ventricular dysfunction. 🟢In acute rheumatic fever, Aschoff bodies often develop in the myocardium and other parts of the heart. Fibrinous nonspecific pericarditis, sometimes with effusion, occurs only in patients with endocardial inflammation and usually subsides without permanent damage. Characteristic and potentially dangerous valve changes may occur. Acute interstitial valvulitis may cause valvular edema. 🟢In chronic rheumatic heart disease, valve thickening, fusion, and retraction or other destruction of leaflets and cusps may occur, leading to stenosis or insufficiency. Similarly, chordae tendineae can shorten, thicken, or fuse, worsening regurgitation of damaged valves or causing regurgitation of an otherwise unaffected valve. Dilation of valve rings may also cause regurgitation. Rheumatic valvular disease most commonly involves the mitral and aortic valves. The tricuspid and pulmonic valves are seldom if ever affected in isolation. 🔴In acute rheumatic fever, the most common cardiac manifestations are 
🔹Mitral regurgitation 
🔹Pericarditis 
🔹Sometimes aortic regurgitation 🔴In chronic rheumatic heart disease, the most common cardiac manifestations are 
🔹Mitral stenosis 
🔹Aortic regurgitation (often with some degree of stenosis) 
🔹Perhaps tricuspid regurgitation (often along with mitral stenosis) By: https://www.instagram.com/tv/CbJ6K0bjT0p/?utm_medium=copy_link