PEDIATRICS Vol. 121 No. 4 April 2008, pp. 864-865 (doi:10.1542/peds.2008-0147)
LETTER TO THE EDITOR |
Cardiac Troponins in Pediatric Myocarditis: In Reply
Stephen B. Freedman, MDCM, MSCI, FRCPCJ. Kimberly Haladyn, BSc
Jennifer Thull-Freedman, MD, MSCI
Division of Pediatric Emergency Medicine
Hospital for Sick Children, University of Toronto
Toronto, Ontario, Canada M5G 1X8
Alejandro Floh, MD, FRCPC
Joel A. Kirsh, MD, FRCPC
Division of Cardiology
Hospital for Sick Children, University of Toronto
Toronto, Ontario, Canada M5G 1X8
Glenn Taylor, MD, FRCPC
Division of Pathology
Hospital for Sick Children, University of Toronto
Toronto, Ontario, Canada M5G 1X8
We thank Lippi et al for their insightful comments regarding the potential role of cardiac troponin in pediatric myocarditis. The objective of our article was to highlight the clinical presentation of children who were eventually diagnosed with myocarditis and review the sensitivity of the initial tests that were performed on these children. Unfortunately, very few children present with myocarditis-specific symptoms. Hence, they undergo investigations on the basis of their presenting symptoms, and the diagnosis of myocarditis is subsequently suspected because of unexplained abnormalities in tests such as those we reported. Once myocarditis is suspected, checking serum troponin values may be indicated.
As pointed out by Lippi et al, our study was limited by our inability to retrospectively determine the denominator on whom the tests we evaluated were performed, and thus, we cannot report on their specificity. We do concur nonetheless that the specificity of liver transaminases is likely low; however, we hope that we have highlighted that when they are elevated without a clear explanation, clinicians should consider the diagnosis of myocarditis.
Although we would have liked to have been able to better evaluate the role of serum troponin, this was not feasible, because of the limited number of children in whom these tests were performed.1 Despite the improved diagnostic characteristics of cardiac troponins compared with more conventional enzymes such as creatinine kinase, we disagree that there is sufficient evidence to claim that troponins are highly sensitive in identifying myocarditis. In fact, the study referred to by Lippi et al reported a sensitivity of only 71% for cardiac troponin T.2 Thus, clinicians should not rely solely on cardiac troponins to determine the likelihood of myocarditis.
As we have described, pediatric myocarditis can, and does, present like many other more common pediatric illness such as asthma, pneumonia, or acute gastroenteritis. Clearly, clinicians should not perform troponins on all such children. We hope our article raises the consideration of myocarditis in such children, and in the vast majority of cases, myocarditis can be ruled out clinically. When the diagnosis of myocarditis is entertained, given the excellent combined sensitivity of the electrocardiogram plus chest radiograph, we suggest screening with these tests initially. If the clinical suspicion is low and the electrocardiogram normal, then likely little additional investigation is required. If the clinical suspicion is high, such as in states of new-onset congestive heart failure, then, regardless of the electrocardiogram or other investigations, cardiology consultation is required. In addition, on the basis of our findings, we suggest that the diagnosis of myocarditis be considered in children for whom the diagnosis was not initially considered, yet are found to have elevated transaminases. Finally, given the exceedingly low frequency of myocarditis in children evaluated in an emergency department with chest pain (<1%)3 and the only moderate sensitivity of serum troponins,2 it does not seem rational to recommend performing such tests routinely, particularly when 1 considers the limited availability and cost of troponin testing in many pediatric institutions.
REFERENCES
- Freedman SB, Haladyn JK, Floh A, Kirsh JA, Taylor G, Thull-Freedman J. Pediatric myocarditis: emergency department clinical findings and diagnostic evaluation.
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[Abstract/Free Full Text] - 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]
- Massin MM, Bourguignont A, Coremans C, Comte L, Lepage P, Gerard P. Chest pain in pediatric patients presenting to an emergency department or to a cardiac clinic.
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[Abstract/Free Full Text]
PEDIATRICS (ISSN 1098-4275). ©2008 by the American Academy of Pediatrics
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