Acute Rheumatic Fever Diagnosis and Management

Acute Rheumatic Fever remains a significant cause of cardiovascular morbidity, particularly in developing regions. It is an autoimmune multisystem inflammatory response following a Group A Streptococcal pharyngitis, mediated by molecular mimicry between streptococcal M proteins and human host tissues (specifically cardiac myosin and laminin on the surface of valves).

Revised Jones Criteria (2015 AHA Update)

The 2015 revision is the current gold standard, emphasizing the distinction between low-risk and moderate/high-risk populations.

Initial Episode Diagnosis

• Requirements: Evidence of preceding GAS infection (elevated ASO or Anti-DNase B titers, positive throat culture, or rapid antigen test) PLUS:
  • 2 Major criteria OR
  • 1 Major + 2 Minor criteria.

Recurrent Episode Diagnosis

• Requirements: Evidence of preceding GAS infection (elevated ASO or Anti-DNase B titers, positive throat culture, or rapid antigen test) PLUS:
  • 2 Major criteria OR
  • 1 Major + 2 Minor criteria OR
  • 3 Minor criteria

Diagnostic Criteria Table

Category	Low-Risk Populations	Moderate-to-High Risk Populations
Major Criteria	• Carditis (Clinical or Subclinical) • Polyarthritis • Chorea • Erythema marginatum • Subcutaneous nodules	• Carditis (Clinical or Subclinical) • Monoarthritis or Polyarthralgia • Chorea • Erythema marginatum • Subcutaneous nodules
Minor Criteria	• Polyarthralgia • Fever (≥ 38.5°C) • ESR ≥ 60 mm/hr and/or CRP ≥ 3.0 mg/dL • Prolonged PR interval	• Monoarthralgia • Fever (≥ 38°C) • ESR ≥ 30 mm/hr and/or CRP ≥ 3.0 mg/dL • Prolonged PR interval

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Subclinical Carditis

A major shift in the 2015 update was the inclusion of subclinical carditis. Echocardiographic evidence of valvulitis (mitral or aortic regurgitation) is now considered a Major criterion even in the absence of a clinical murmur.

• Pathological Regurgitation Criteria for MR: Seen in at least 2 views, Doppler jet length ≥ 2 cm, peak velocity > 3 m/s, and pansystolic jet.
• Pathological Regurgitation Criteria for AR: Seen in at least 2 views, Doppler jet length ≥ 1 cm, peak velocity > 3 m/s, and pandiastolic jet.

Sydenham’s Chorea

Often presents with a long latent period (up to 6 months) after the initial infection. It may occur as the sole manifestation of ARF. In such cases, evidence of a preceding GAS infection is not strictly required for diagnosis, as titers may have already declined.

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Management Framework

Primary Prophylaxis

Immediate treatment of GAS pharyngitis to prevent the initial attack of ARF.

• Standard: Single IM dose of Benzathine Penicillin G or a 10-day course of oral Penicillin V or Amoxicillin.

Secondary Prophylaxis (Prevention of Recurrence)

Essential for preventing the progression to chronic Rheumatic Heart Disease (RHD).

• Duration without Carditis: 5 years or until age 21 (whichever is longer).
• Duration with Carditis (No residual RHD): 10 years or until age 21 (whichever is longer).
• Duration with Persistent RHD: 10 years or until age 40; sometimes lifelong if high risk.

Anti-inflammatory Therapy

• Salicylates: High-dose Aspirin for arthritis.
• Corticosteroids: Prednisone is generally reserved for severe carditis with heart failure, though its impact on long-term valvular outcomes compared to aspirin remains debated.