Published online April 1, 2008
PEDIATRICS Vol. 121 No. 4 April 2008, pp. 864 (doi:10.1542/10.1542/peds.2008-0031)

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LETTER TO THE EDITOR

Cardiac Troponins in Pediatric Myocarditis

Giuseppe Lippi, MD
Gian Luca Salvagno, MD
Gian Cesare Guidi, MD
Sezione di Chimica e Clinica
Dipartimento di Patologia, Università di Verona
37134 Verona, Italy

To the Editor.—

We read with interest the article of Freedman et al¹ on the diagnostic evaluation of pediatric myocarditis, concluding that serum aspartate aminotransferase (AST) was the most sensitive biomarker for myocarditis among those evaluated. It was also suggested that screening tests should include chest radiographs and ECGs, although elevated liver enzymes may raise additional concern in the appropriate clinical scenario.

There are several issues to be emphasized in the use of laboratory markers for diagnosing myocarditis. None of the markers evaluated by Freedman et al,¹ including AST and alanine aminotransferase (ALT), are cardiospecific. Regardless of an acceptable sensitivity (85%), the specificity of either AST or ALT is expectedly low in patients with myocarditis because of coexistence of systemic or organ dysfunction, which would cause both tests to have little clinical utility. Although most available studies involve adult patients, it is acknowledged that cardiospecific troponins provide evidence of myocyte injury in patients with myocarditis more sensitively than do conventional cardiac enzymes.² Not only has it been demonstrated that troponin T (TnT) has high sensitivity and specificity for diagnosing myocarditis but also Franz et al³ observed constantly increased TnT levels (3- to 60-fold), from 2 to 8 days after onset of chest pain. Smith et al⁴ noted a direct relation between the size of myocardial inflammation and troponin I (TnI) levels. In comparison with creatine kinase activities, TnT also provides improved sensitivity for detection of micronecrosis because of a proportionally higher and longer-lasting increase in the blood.⁵ Although additional studies are advisable, current scientific data suggest that troponins would provide superior information than liver enzymes in pediatric myocarditis.

REFERENCES

1. Freedman SB, Haladyn JK, Floh A, Kirsh JA, Taylor G, Thull-Freedman J. Pediatric myocarditis: emergency department clinical findings and diagnostic evaluation. Pediatrics. 2007;120 (6):1278 –1285[Abstract/Free Full Text]
2. Lauer B, Niederau C, Kühl U, et al. Cardiac troponin T in patients with clinically suspected myocarditis. J Am Coll Cardiol. 1997;30 (5):1354 –1359[Abstract]
3. Franz WM, Remppis A, Kandolf R, Kübler W, Katus HA. Serum troponin T: diagnostic marker for acute myocarditis. Clin Chem. 1996;42 (2):340 –341[Free Full Text]
4. Smith SC, Ladenson JH, Mason JW, et al. Elevations of cardiac troponin I associated with myocarditis: experimental and clinical correlates. Circulation. 1997;95 (1):163 –168[Abstract/Free Full Text]
5. Soongswang J, Durongpisitkul K, Nana A, et al. Cardiac troponin T: a marker in the diagnosis of acute myocarditis in children. Pediatr Cardiol. 2005;26 (1):45 –49[CrossRef][Web of Science][Medline]

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PEDIATRICS (ISSN 1098-4275). ©2008 by the American Academy of Pediatrics

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This Article Extract Full Text (PDF) Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services E-mail this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to My File Cabinet Download to citation manager Request Permissions Citing Articles Citing Articles via CrossRef Citing Articles via Google Scholar Google Scholar Articles by Lippi, G. Articles by Guidi, G. C. Search for Related Content PubMed PubMed Citation Articles by Lippi, G. Articles by Guidi, G. C. Related Collections Heart & Blood Vessels Social Bookmarking                         What's this?