28  Rheumatic Heart Disease

28.1 Introduction

Rheumatic heart disease (RHD) is a chronic condition resulting from acute rheumatic fever (ARF), an autoimmune response to group A beta-hemolytic streptococcal (GAS) pharyngitis. It is characterized by permanent damage to the heart valves, particularly the mitral and aortic valves, due to repeated episodes of inflammation and scarring. RHD remains a significant cause of morbidity and mortality among children and young adults in low- and middle-income countries. Early diagnosis and management of ARF and RHD are critical to prevent severe complications and improve outcomes.

28.2 Incidence and Prevalence

RHD affects approximately 40 million people worldwide, with the highest burden in sub-Saharan Africa, South Asia, the Pacific Islands, and parts of Latin America. The global prevalence in children aged 5–15 years is estimated at 1–3 per 1,000, but it can exceed 10 per 1,000 in high-risk populations. ARF, the precursor to RHD, occurs most commonly between 5 and 15 years of age, with peak incidence following untreated or inadequately treated GAS pharyngitis.

28.3 Etiology

The primary etiology of RHD is recurrent ARF episodes triggered by an immune response to GAS infection. The following factors contribute to its development:

1. Infectious Agent: GAS infection, particularly of the throat, is necessary to initiate the autoimmune process. Certain GAS strains (M-protein serotypes) are more rheumatogenic.
2. Host Susceptibility: Genetic predisposition plays a role, with family clustering observed in affected individuals.
3. Environmental Factors: Overcrowding, poor hygiene, and limited access to healthcare increase the risk of GAS infections and progression to ARF and RHD.

RHD develops through the following sequence:

1. GAS Pharyngitis: GAS infection elicits an immune response involving antibodies and T-cells targeting streptococcal antigens.
2. Molecular Mimicry: Cross-reactivity occurs between streptococcal antigens (e.g., M protein) and human proteins in the heart, joints, brain, and skin. Autoimmune inflammation leads to tissue damage.
3. Acute Rheumatic Fever: Pancarditis (endocarditis, myocarditis, and pericarditis) is the hallmark of ARF. The endocardium is most affected, leading to valvulitis.
4. Chronic RHD: Recurrent inflammation and scarring cause permanent valvular damage, predominantly affecting the mitral and aortic valves. Mitral stenosis is the most common lesion, followed by mitral regurgitation and aortic regurgitation.

28.4 Signs and Symptoms

The clinical presentation of RHD varies based on the severity of valvular involvement and associated complications.

1. Symptoms:
   • Fatigue and exercise intolerance
   • Dyspnea, initially on exertion and later at rest
   • Palpitations due to arrhythmias (e.g., atrial fibrillation)
   • Cough and hemoptysis (in severe mitral stenosis)
   • Edema and signs of heart failure in advanced cases
2. Signs:

   • Cardiac Murmurs:

     • Mitral stenosis: Low-pitched diastolic murmur with an opening snap.
     • Mitral regurgitation: holosystolic murmur at the apex
     • Aortic regurgitation: High-pitched diastolic murmur.

   • Cardiomegaly with a displaced apex beat

   • Signs of pulmonary hypertension (e.g., loud pulmonary component of S2)

   • Peripheral edema, hepatomegaly, and ascites in heart failure

3. History of ARF:
   • Clinical features such as migratory polyarthritis, carditis, chorea, subcutaneous nodules, or erythema marginatum support prior episodes of ARF.

28.5 Investigations

The diagnosis of RHD involves clinical assessment, laboratory tests, and imaging studies.

1. Laboratory Tests:
   • Throat Culture or Rapid Antigen Test: To confirm GAS infection if suspected.
   • Anti-Streptolysin O (ASO) Titer: Elevated in recent GAS infections.
   • C-reactive protein (CRP) and Erythrocyte Sedimentation Rate (ESR): Markers of inflammation during ARF episodes.
2. Imaging:
   • Echocardiography:
     • Key diagnostic tool for detecting valvular lesions and assessing severity.
     • Common findings include leaflet thickening, restricted mobility, and regurgitation or stenosis
   • Chest X-Ray:
     • Cardiomegaly and pulmonary congestion in advanced disease.
   • Electrocardiogram (ECG):
     • Prolonged PR interval (first-degree heart block) in ARF.
     • Atrial fibrillation or other arrhythmias in chronic RHD
3. Other Tests:
   • Cardiac MRI in selected cases for detailed assessment of myocardial and valvular involvement.

28.6 Treatment

Management of RHD aims to reduce symptoms, prevent disease progression, and address complications.

1. Medical Management:
   • Antibiotic Prophylaxis: Long-term benzathine penicillin G intramuscular injections every 3–4 weeks to prevent recurrent ARF episodes.
   • Heart Failure Management: Diuretics, ACE inhibitors, and beta-blockers for symptomatic relief.
   • Anticoagulation: Warfarin for patients with atrial fibrillation or mechanical valve replacement.
   • Anti-Inflammatory Therapy: Aspirin or corticosteroids for active carditis.
2. Surgical and Interventional Treatment:
   • Valvuloplasty:
     • Percutaneous balloon mitral valvotomy for mitral stenosis in suitable candidates
   • Valve Repair or Replacement:
     • Required for severe valvular dysfunction or when medical management fails.

28.7 Prevention

The cornerstone of RHD prevention is the timely diagnosis and treatment of GAS pharyngitis and ARF.

1. Primary Prevention:
   • Early recognition and antibiotic treatment of streptococcal pharyngitis with penicillin or amoxicillin.
   • Improved hygiene and reduced overcrowding to lower transmission risk.
2. Secondary Prevention:
   • Long-term antibiotic prophylaxis to prevent recurrent ARF.
   • Duration of prophylaxis:
     • At least 10 years after the last episode of ARF or until the patient is 21 years old, whichever is longer.
     • Life-long prophylaxis for severe valvular disease or post-surgical cases
3. Community Interventions
   • Public health programs to increase awareness and access to healthcare in high-burden regions.

28.8 Complications

RHD can lead to severe complications if not adequately managed:

1. Heart Failure: Due to progressive valvular dysfunction and increased cardiac workload.
2. Atrial Fibrillation: Common in mitral stenosis, leading to thromboembolic events like stroke.
3. Pulmonary Hypertension: Resulting from chronic left-sided valvular disease.
4. Infective Endocarditis: Increased risk in patients with damaged valves.
5. Pregnancy Complications: Significant maternal and fetal risks due to increased hemodynamic demands.

28.9 Prognosis

The prognosis of RHD depends on the severity of valvular involvement, the effectiveness of secondary prophylaxis, and access to medical and surgical care. Without intervention, severe RHD can result in progressive heart failure, significant morbidity, and premature death. With timely diagnosis and appropriate management, many children can experience improved quality of life and survival.

28.10 Differential Diagnosis

Several conditions can mimic the clinical presentation of RHD and should be considered:

1. Congenital Heart Disease: Examples include atrial septal defect, ventricular septal defect, and patent ductus arteriosus.
2. Infective Endocarditis: Characterized by fever, new murmur, and signs of embolization.
3. Kawasaki Disease: Vasculitis with coronary artery involvement, fever, and mucocutaneous inflammation.
4. Myocarditis: Viral or autoimmune causes leading to cardiac inflammation.
5. Mitral Valve Prolapse:
   • Can mimic mitral regurgitation murmurs

28.11 Conclusion

Rheumatic heart disease remains a major public health challenge in developing countries, disproportionately affecting children and young adults. Early recognition and treatment of GAS pharyngitis and consistent secondary prophylaxis are essential to prevent the progression to RHD. Multidisciplinary care, including medical, surgical, and public health interventions, is crucial to improving outcomes and reducing the global burden of this preventable disease.

---