Can rheumatic fever elevate troponin levels?

Troponin Elevation in Rheumatic Fever

Rheumatic fever typically does not cause significant troponin elevation, as multiple studies have consistently demonstrated normal troponin levels in patients with rheumatic carditis. 1, 2, 3, 4

Evidence on Troponin in Rheumatic Fever

Systematic Studies Show No Elevation

• Multiple prospective studies have specifically examined troponin levels in rheumatic fever patients:
  • A study of 16 patients with acute rheumatic carditis found no elevated cardiac troponin I levels, suggesting minimal myocytic necrosis 1
  • A larger prospective study of 108 consecutive patients with ARF showed no significant difference in mean cardiac troponin I values between patients with and without carditis 2
  • Another systematic study of 95 consecutive patients with ARF reported mean cTnI of 0.077±0.017 ng/ml (normal <0.1 ng/ml), with no significant differences between groups with and without carditis 3
  • A study examining cardiac troponin T in 30 ARF patients found normal levels in all except one patient with congestive heart failure 4

Pathophysiological Explanation

• The absence of troponin elevation suggests that inflammation rather than myocardial necrosis is the predominant mechanism in rheumatic carditis 4
• This supports the concept that acute valvular regurgitation, not myocardial injury, is the major hemodynamic abnormality in these patients 1
• Even in patients with rheumatic carditis and heart failure, troponin levels typically remain normal, with heart failure being attributed to severe valvular regurgitation rather than myocardial dysfunction 3

Differential Diagnosis: When Troponin IS Elevated

If troponin elevation is found in a patient with suspected rheumatic fever, clinicians should consider alternative diagnoses:

1. Nonrheumatic streptococcal myocarditis: A distinct entity from ARF that can present with elevated troponins, as reported in a case with troponin levels peaking at 4.0 ng/L 5

2. Other causes of myocardial injury: According to guidelines, many conditions can cause troponin elevation 6:

   • Myocarditis (non-rheumatic)
   • Takotsubo syndrome
   • Pulmonary embolism
   • Heart failure
   • Tachyarrhythmias
   • Hypertensive emergencies
   • Critical illness

Clinical Implications

Diagnostic Value

• Normal troponin levels in a patient with suspected rheumatic carditis are consistent with the diagnosis
• Elevated troponins should prompt consideration of alternative diagnoses, particularly non-rheumatic streptococcal myocarditis 5
• Cardiac MRI can help differentiate between rheumatic carditis and non-rheumatic myocarditis 5

Prognostic Value

• The absence of troponin elevation in rheumatic carditis suggests a different pathophysiology than other forms of myocarditis
• Heart failure in rheumatic carditis is primarily due to valvular regurgitation rather than myocardial dysfunction 2, 3
• Echocardiographic assessment of valvular function is more important than troponin measurement for prognosis in rheumatic carditis

Conclusion

The evidence consistently shows that rheumatic fever, even with carditis, does not typically cause significant troponin elevation. If troponin elevation is detected in a patient with suspected rheumatic fever, clinicians should strongly consider alternative diagnoses such as non-rheumatic streptococcal myocarditis or other causes of myocardial injury.