Rheumatic Heart Disease I: Introduction

Rheumatic heart disease develops after untreated or inadequately treated group A streptococcal pharyngitis. The infection triggers an autoimmune response where the immune system mistakenly attacks heart tissues due to molecular mimicry between streptococcal M proteins and cardiac myosin. This leads to pancarditis and valvulitis, causing permanent valve damage and chronic heart dysfunction.

Acute rheumatic fever typically develops approximately 2 to 4 weeks after a group A streptococcal pharyngitis infection. During this period, the immune system begins its autoimmune attack on cardiac tissues. Early recognition and treatment of streptococcal infections can prevent progression to rheumatic fever and subsequent chronic rheumatic heart disease.

Valvulitis causes swelling and erosion of the mitral and aortic valves, with fibrin and blood cell deposition forming vegetations. These lesions thicken valve leaflets, fuse commissures and chordae tendineae, and cause papillary muscle fibrosis. Over time, valve leaflets calcify, resulting in stenosis that narrows the valve opening and regurgitation where blood leaks backward.

Aschoff bodies are nodules formed from inflammatory reactions that destroy myocardial collagen fibers. As they mature, they become fibrotic, forming scar tissue within the heart muscle. This scarring impairs the myocardium's contractile function, contributing to overall cardiac dysfunction and reduced heart pumping ability in rheumatic heart disease.

Rheumatic pericarditis inflames both pericardial layers, causing thickening and fibrinous exudate formation. A serosanguineous pericardial effusion containing blood and serum may develop. During healing, fibrosis and adhesions can form, potentially obliterating the pericardial sac and restricting heart movement and function.

While group A Streptococcus is the causative agent, malnutrition, overcrowding, poor hygiene, and lower socioeconomic status predispose individuals to rheumatic fever. These factors compromise immune function and increase infection severity. Recurrent streptococcal infections exacerbate cardiac damage, leading to progressive structural deterioration and complications including heart failure and atrial fibrillation.

Each recurrent streptococcal infection triggers additional inflammation and autoimmune attacks on cardiac tissues. Progressive structural damage accumulates with each episode, worsening valve dysfunction and myocardial scarring. Understanding clinical manifestations and diagnostic studies helps identify disease progression early and guides appropriate management to prevent severe complications.