Rheumatic Fever, Acute

KEY FEATURES

ESSENTIALS OF DIAGNOSIS

• Carditis in almost 50% of those with acute rheumatic fever: heart failure, new regurgitant heart murmur (mitral or aortic regurgitation), pericarditis

• Evidence of streptococcal infection: throat culture, detection of streptococcal antibodies

• Chorea

• Polyarthritis

• Typical skin findings: subcutaneous nodules, erythema marginatum

GENERAL CONSIDERATIONS

• Rheumatic fever is the most common cause of cardiac disease worldwide in children and young adults

• The disease is more common in developing countries (100 per 100,000) compared with developed countries (2 per 100,000)

• The rheumatogenic strains of Streptococcus have M proteins that share epitopes with cardiac myosin and sarcolemmal membrane proteins

  • – Host antibodies against these epitopes cross-react with cardiac tissue, producing an inflammatory disease of all 3 layers of the heart

• During an outbreak of group A streptococcal pharyngitis, up to 5% get rheumatic fever

• The characteristic lesion in cardiac tissue samples is composed of multinucleated giant cells and is called an Aschoff nodule

  • – These nodules are seen only in cardiac tissue despite widespread inflammation in other tissues

• Long-term sequelae of rheumatic fever occur only in the heart despite acute involvement of other tissue

• The mitral valve is most commonly affected, followed by aortic, tricuspid, and pulmonic valves

• The valves are thickened from inflammation, and the annuli are dilated, producing regurgitation (the most common finding)

• Pericarditis is frequent, but tamponade is rare

CLINICAL PRESENTATION

SYMPTOMS AND SIGNS

• Major manifestations:

  • – Polyarthritis

  • – Chorea

  • – Subcutaneous nodules

  • – Erythema margination

  • – Carditis (eg, new valve regurgitation murmurs)

• Minor manifestations:

  • – Arthralgia

  • – Fever

  • – Elevated acute-phase reactants (eg, erythrocyte sedimentation rate [ESR] and C-reactive protein)

  • – Prolonged PR interval on ECG

• Supporting evidence of antecedent group A streptococcal infection:

  • – Positive throat culture

  • – Positive rapid streptococcal antibody test

  • – Elevated or rising streptococcal antibody titer

• The modified Jones Criteria for the diagnosis of rheumatic fever require 2 major criteria or 1 major and 2 minor criteria with supporting evidence of streptococcal infection

PHYSICAL EXAM FINDINGS

• Carditis:

  • – Apical pansystolic murmur of mitral regurgitation

  • – Apical mid-diastolic murmur (Carey Coombs murmur)

  • – Basal diastolic decrescendo murmur of aortic regurgitation (50%)

• Polyarthritis: 2 or more large joints (knees, ankles, elbows, wrists) showing redness, swelling, and heat in a migratory pattern for 1 day to 3 weeks

• Chorea (a late manifestation [3 or more months after infection]): involuntary movements while awake

• Erythema margination: pink macular nonpruritic rash on the trunk or extremities (never the face), which appear as rings that may coalesce and look serpiginous (10%)

• Subcutaneous nodules: discrete firm painless mobile nodules (0.5–2 cm) on the extensor surfaces of joints or bony prominences, which occur about 3 weeks after other signs

DIFFERENTIAL DIAGNOSIS

• Juvenile rheumatic arthritis

• Infective endocarditis

• Myocarditis due to other ...