Infectious Disease · Cardiology
The facts most likely to be tested
Acute Rheumatic Fever is a Type II hypersensitivity reaction occurring as a sequela of untreated Group A Streptococcus (GAS) pharyngitis.
The diagnosis is established using the Jones Criteria, requiring evidence of a recent GAS infection plus either two major criteria or one major and two minor criteria.
The major Jones criteria include carditis, migratory polyarthritis, Sydenham chorea, erythema marginatum, and subcutaneous nodules.
Carditis is the most serious manifestation, typically presenting as pancarditis involving the mitral valve and potentially leading to chronic rheumatic heart disease.
Sydenham chorea is a late-onset neurological manifestation characterized by involuntary, jerky, purposeless movements and emotional lability.
Erythema marginatum presents as a serpiginous, erythematous rash with central clearing that is typically found on the trunk and proximal extremities.
The primary treatment for acute disease is penicillin to eradicate the GAS infection, followed by long-term antibiotic prophylaxis to prevent recurrent episodes.
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A 9-year-old boy is brought to the clinic by his mother due to involuntary, jerky movements of his hands and face that started two weeks ago. Three weeks prior, he had a sore throat that was left untreated. On physical examination, he has a new-onset holosystolic murmur at the apex and migratory polyarthritis affecting his knees and ankles. His temperature is 100.4°F (38°C), and his erythrocyte sedimentation rate (ESR) is elevated.
What is the most appropriate next step in management to prevent long-term cardiac complications?
Intramuscular benzathine penicillin G
The patient meets the Jones criteria (chorea, carditis, polyarthritis, and evidence of recent GAS infection), confirming Acute Rheumatic Fever; secondary prophylaxis with antibiotics is essential to prevent recurrent GAS infections and worsening rheumatic heart disease.
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Etiology / Epidemiology
Follows Group A Streptococcus (GAS) pharyngitis in children aged 5-15. Caused by molecular mimicry.
Clinical Manifestations
Jones Criteria required for diagnosis. Sydenham chorea and erythema marginatum are pathognomonic.
Diagnosis
Jones Criteria (2 major or 1 major + 2 minor) + evidence of recent GAS infection.
Treatment
Penicillin G is the drug of choice. Aspirin for arthritis; corticosteroids for carditis.
Prognosis
Rheumatic heart disease (mitral stenosis) is the primary long-term morbidity.
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Epidemiology & Etiology
Occurs 2-4 weeks after untreated or inadequately treated Group A Strep pharyngitis. Primarily affects children aged 5-15 years in resource-limited settings. It is an autoimmune response to streptococcal cell wall antigens.
Pertinent Anatomy
The heart is the primary target, specifically the mitral valve. Inflammation leads to Aschoff bodies within the myocardium. Chronic damage results in valvular scarring and stenosis.
Pathophysiology
Host antibodies cross-react with human cardiac, joint, and CNS tissues via molecular mimicry. This triggers a systemic inflammatory cascade. The process is a Type II hypersensitivity reaction.
Clinical Manifestations
Major criteria include carditis, polyarthritis (migratory), Sydenham chorea, erythema marginatum, and subcutaneous nodules. Minor criteria include fever, elevated ESR/CRP, and prolonged PR interval. Carditis is the most serious manifestation, potentially leading to heart failure.
Diagnosis
Diagnosis requires the Jones Criteria plus evidence of recent GAS infection (e.g., ASO titer or positive rapid antigen test). Echocardiogram is the gold standard to evaluate for valvular involvement. Elevated ASO titers confirm the preceding infection.
Treatment
Penicillin G (IM) is the first-line treatment to eradicate residual GAS. Use aspirin for arthritis and corticosteroids for severe carditis. Penicillin allergy requires macrolides like azithromycin. Long-term prophylactic antibiotics are required to prevent recurrence.
Prognosis
The most significant complication is chronic rheumatic heart disease, specifically mitral stenosis. Patients require long-term antibiotic prophylaxis to prevent recurrent attacks, which increase the risk of progressive valvular damage.
Differential Diagnosis
Post-streptococcal reactive arthritis: lacks carditis
Juvenile idiopathic arthritis: persistent, not migratory
Infective endocarditis: positive blood cultures
Lyme disease: associated with tick exposure/rash
Systemic Lupus Erythematosus: positive ANA/dsDNA