Can scarlet fever cause mitral stenosis in adulthood?

Scarlet Fever and Mitral Stenosis: The Rheumatic Connection

Yes, scarlet fever is a significant cause of mitral stenosis in adulthood through its association with acute rheumatic fever, which can lead to rheumatic heart disease and subsequent valvular damage. 1

Pathophysiological Mechanism

Scarlet fever is caused by group A beta-hemolytic streptococcus (GABHS), the same organism responsible for streptococcal pharyngitis. When inadequately treated, this infection can trigger acute rheumatic fever, which involves an autoimmune response that damages heart valves, particularly the mitral valve.

The progression typically follows this sequence:

1. Untreated or inadequately treated GABHS pharyngitis/scarlet fever
2. Development of acute rheumatic fever (2-3 weeks after infection)
3. Rheumatic carditis with valve inflammation
4. Progressive valve damage with commissural fusion, leaflet thickening, and calcification
5. Development of mitral stenosis years to decades later

Epidemiology and Clinical Significance

• Rheumatic fever remains the primary cause of mitral stenosis worldwide 1
• In developed countries, the incidence has dramatically declined over the past 70 years 2
• However, rheumatic mitral stenosis still causes significant morbidity and mortality globally 3
• In developing countries and among immigrants from these regions, mitral stenosis maintains high prevalence 2

Clinical Presentation and Progression

Rheumatic mitral stenosis typically presents differently based on geographic location:

• In high-prevalence regions: Younger patients (teens to 30 years) with commissural fusion but pliable, non-calcified valve leaflets
• In low-prevalence regions: Older patients (50-70 years) presenting decades after the initial rheumatic fever with calcified fibrotic leaflets 1

The disease progresses through defined stages:

1. Stage A: At risk (mild valve doming)
2. Stage B: Progressive MS (valve area >1.5 cm²)
3. Stage C: Asymptomatic severe MS (valve area ≤1.5 cm²)
4. Stage D: Symptomatic severe MS (valve area ≤1.5 cm², with symptoms) 1

Prevention Strategies

Primary Prevention

• Prompt recognition and treatment of streptococcal pharyngitis/scarlet fever 1
• Rapid streptococcal testing and appropriate antibiotic therapy

Secondary Prevention

For patients who have had rheumatic fever (with or without carditis):

• Benzathine penicillin G: 1.2 million units IM every 4 weeks (or every 3 weeks in high-risk patients) 4
• Alternative regimens for penicillin-allergic patients:
  • Sulfadiazine: 1g daily (>27kg) or 0.5g daily (≤27kg)
  • Penicillin V: 250mg twice daily
  • Erythromycin: 250mg twice daily 1, 4

Duration of Prophylaxis

• Rheumatic fever with carditis and residual heart disease: 10 years or until age 40, whichever is longer (sometimes lifelong)
• Rheumatic fever with carditis but no residual heart disease: 10 years or until age 21, whichever is longer
• Rheumatic fever without carditis: 5 years or until age 21, whichever is longer 4

Management Considerations

For established mitral stenosis:

• Medical management (beta blockers, diuretics) may help with mild MS
• Percutaneous mitral balloon commissurotomy for suitable valve anatomy
• Surgical intervention (valve repair or replacement) for severe cases 1

Important Clinical Pearls

• Juvenile mitral stenosis (detected before age 20) constitutes 25-40% of all isolated mitral stenosis cases 5
• Mitral stenosis is rarely complicated by infective endocarditis, but this diagnosis should not be excluded in developing countries 6
• Rheumatic fever can also cause mitral valve prolapse with pure mitral regurgitation without stenosis 7
• Failure to recognize mitral stenosis not only precludes effective therapies but may result in serious complications 2

Conclusion

The connection between scarlet fever and mitral stenosis is well-established through the rheumatic fever pathway. While the incidence has declined in developed countries, understanding this relationship remains clinically important, especially for populations with higher rheumatic fever prevalence.