What is the treatment approach for an adult patient with rheumatic fever?

Treatment for Adults with Rheumatic Fever

Adults with acute rheumatic fever should receive a full 10-day course of penicillin to eradicate Group A Streptococcus, followed immediately by continuous long-term secondary prophylaxis with intramuscular benzathine penicillin G (1.2 million units every 4 weeks), plus anti-inflammatory therapy with high-dose aspirin or corticosteroids for symptom control. 1, 2, 3

Acute Phase Treatment

Antibiotic Eradication Therapy

• Administer a complete 10-day therapeutic course of penicillin to eradicate residual Group A Streptococcus, even if throat culture is negative at diagnosis. 1, 2
• For adults, use oral penicillin V 500 mg 2-3 times daily for 10 days. 1
• For penicillin-allergic patients, substitute erythromycin or first-generation cephalosporins (if no immediate-type hypersensitivity). 1, 2

Anti-Inflammatory Management

• Adults with rheumatic fever characteristically present with severe, febrile migratory polyarthritis primarily affecting large joints in the lower extremities, and respond promptly and dramatically to high-dose aspirin therapy. 4
• For severe inflammation or cardiac involvement, consider corticosteroids such as prednisone at 1-2 mg/kg/day for 1-2 weeks. 1
• In severe cases with significant cardiac involvement (such as pericarditis), intravenous methylprednisolone (1000 mg/day initially) may be considered, followed by oral prednisone. 1

Important Clinical Context for Adults

• Carditis occurs in only approximately 15% of adults with acute rheumatic fever and is typically mild and transient, unlike in children. 4
• Expect erythrocyte sedimentation rate (Westergren) greater than 100 mm/hr as a characteristic laboratory finding. 4
• Mild and transient abnormalities of renal function (51%) and hepatic function (64%) may occur but are not aspirin-mediated. 4

Secondary Prophylaxis (Critical for Prevention)

Preferred Regimen

• Intramuscular benzathine penicillin G 1.2 million units every 4 weeks is the first-line prophylaxis and is approximately 10 times more effective than oral antibiotics at preventing rheumatic fever recurrence. 1, 5, 3, 6
• In high-risk populations or patients with recurrences despite adherence to the 4-week regimen, administer every 3 weeks. 1, 5
• Moderate-certainty evidence shows intramuscular penicillin reduces rheumatic fever recurrence to 0.1% compared to 1% with oral antibiotics. 6

Alternative Regimens for Penicillin Allergy

• For patients allergic to both penicillin and sulfonamides, use oral erythromycin 250 mg twice daily for long-term prophylaxis. 7, 2, 3
• This is a third-line option only after benzathine penicillin G (first-line) and sulfadiazine (second-line for penicillin allergy). 7

Duration of Prophylaxis (Age and Disease-Dependent)

• Patients with rheumatic carditis and residual heart disease: Continue for 10 years after the last episode OR until 40 years of age (whichever is longer), sometimes lifelong. 1, 5
• Patients with rheumatic carditis but no residual heart disease: Continue for 10 years OR until 21 years of age (whichever is longer). 1, 5
• Patients without carditis: Continue for 5 years OR until 21 years of age (whichever is longer). 1, 7
• Prophylaxis should continue even after valve surgery, including prosthetic valve replacement. 1

Critical Pitfalls to Avoid

Common Errors

• Do not delay initiation of secondary prophylaxis—it should begin as soon as acute rheumatic fever is diagnosed. 1
• Do not assume optimal treatment of streptococcal pharyngitis prevents rheumatic fever; at least one-third of cases result from asymptomatic Group A Streptococcus infections. 1
• Do not prescribe erythromycin as first-line prophylaxis when penicillin or sulfadiazine can be used—erythromycin is only for patients with dual allergies. 7
• For patients already receiving penicillin prophylaxis who require endocarditis prophylaxis for dental procedures, use an agent other than penicillin due to likely oral α-hemolytic streptococci resistance. 5

Medication Safety Considerations

• Macrolides like erythromycin can cause dose-dependent QT interval prolongation and should not be combined with cytochrome P-450 3A inhibitors (azole antifungals, HIV protease inhibitors, some SSRIs). 7
• Antibiotics probably carry an increased risk of hypersensitivity reactions and local injection site reactions compared to no antibiotics, but may not affect the risk of anaphylaxis or sciatic nerve injury. 6

Evidence Quality and Strength

The recommendation for intramuscular benzathine penicillin G as first-line prophylaxis carries Class I, Level of Evidence A from the American Heart Association. 5 Moderate-certainty evidence from pooled meta-analysis demonstrates that antibiotics overall reduce rheumatic fever recurrence substantially (0.7% versus 1.7% without antibiotics), with people having early or mild rheumatic heart disease showing the greatest capacity to benefit (8.1% benefit). 6 However, most evidence comes from studies conducted 50-60 years ago, before contemporary echocardiographic techniques, highlighting the need for ongoing research. 6, 8