Rheumatic Heart Disease Overview

Mitral Valve and Acute Rheumatic Fever

• Vegetations form due to fibrin precipitation at eroded inflamed tissues, leading to minor disturbances in cardiac function.
• Mac Callum plaque is characterized by irregular thickening of the left atrial endocardium due to regurgitant jets.
• Chronic rheumatic heart disease involves fibrosis, scarring, thickened valve cusps, and retraction of leaflets.
• Features of mitral valve changes include leaflet thickening, commissural fusion, and alterations in the chordae tendineae, resulting in "fish mouth" or "buttonhole" stenosis.
• Valvular stenosis and regurgitation are the most significant outcomes, with mitral valve involvement in 70% of cases and combined mitral and aortic disease in 25%.
• Left atrial dilation may lead to thrombus formation, while chronic lung congestion can cause pulmonary changes and right ventricular hypertrophy.

Clinical Features of Acute Rheumatic Fever

• Symptoms appear 2-3 weeks after streptococcal infection; common symptoms include fever, migratory polyarthritis, and carditis.
• The disease predominantly affects children aged 5-15, with 20% of cases in adults.
• Clinical manifestations include carditis with pericardial friction rubs, CHF, arrhythmias, chorea, subcutaneous nodules, and erythema marginatum.
• Serologic tests (ASO, DNAse B) are positive, confirming recent streptococcal infection.

Major Manifestations

• Carditis: Pancarditis is the most serious complication, causing dyspnea, chest discomfort, and potential CHF from severe valve insufficiency.
• Arthritis: Most common symptom, starting in lower limb large joints, progressing migratorily. Severity peaks in 12-24 hours, lasting 2-6 days, responsive to aspirin.
• Erythema Marginatum and Subcutaneous Nodules: Lesions appear as raised, non-pruritic macules or papules; subcutaneous nodules are non-tender, usually found over extensor surfaces.

Chronic Rheumatic Heart Disease

• Develops years after acute rheumatic fever, resulting in valvular damage, murmurs, hypertrophy, dilation, and CHF.
• Increased risk of infective endocarditis.

Infective Endocarditis

• A serious infection of heart valves characterized by friable vegetations formed by necrotic debris and organisms.
• Classification:
  • Acute: High virulence organisms affecting normal valves, leading to rapid morbidity.
  • Subacute: Low virulence organisms targeting scarred valves.

Diagnostic Criteria

• Pathologic criteria involve demonstrating microorganisms via culture or histology of vegetations or emboli.
• Major clinical criteria include positive blood cultures and echocardiographic findings; minor criteria involve predisposing factors and non-diagnostic echocardiographic findings.

Nonbacterial Thrombotic Endocarditis (NBTE)

• Characterized by sterile vegetations on valve leaflets, associated with hypercoagulable states, especially in cancer patients.
• Vegetations are small, non-destructive, and adhere loosely; local effects are minor, but they can cause embolic events.

Libman-Sacks Endocarditis

• Associated with SLE, featuring mitral and aortic valve inflammation with sterile vegetations resulting from immune complexes.
• Symptoms may include cardiac failure, embolic events, and manifesting SLE symptoms.

Calcific Aortic Stenosis

• A condition leading to stiff valve leaflets and obstructed left ventricular outflow, often secondary to rheumatic heart disease or congenital defects.
• Risk factors include age, male gender, high LDL, smoking, hypertension, and diabetes.
• Obstruction causes left ventricular hypertrophy, angina, palpitations, dyspnea, and potential heart failure if untreated.

This quiz delves into the implications of acute rheumatic fever on mitral valve function and the development of chronic rheumatic heart disease. It covers the pathological changes such as Mac Callum plaque and valve thickening, and their effects on cardiac performance. Test your understanding of these critical concepts in cardiac pathology.