Background: Coronary artery dilatations are almost always secondary to Kawasaki disease in the pediatric population. The presence of CA involvement is used as a criterion to diagnose incomplete KD disease, which may be challenging. It has been recently demonstrated that febrile patients had larger CA size than non-febrile children in a pilot study. As there is almost always a myocarditis in the acute phase of KD disease we sought to investigate whether viral myocarditis may cause CA dilatations.
Method: This retrospective study reviewed 14 consecutive patients with a diagnosis of viral myocarditis at Saint-Justine Hospital, Montreal, from April 2000 trough December 2010. Kawasaki disease was excluded in all patients. All echocardiogram studies were reviewed by an independent experienced technician for CA size and function parameters. Patients were classified in three categories: definite CA dilatation (Z-score ≥ 2.5 in one or more CA), occult CA dilatation (Z score variation ≥ 2 for the same CA on 2 different echogrardiograms, but absolute Z score always < 2.5) and normal coronary artery. Demographics, laboratory values, microbial etiology testing, diagnostic studies were also collected.
Results: Mean age at presentation was 1.67 ± 3.22 years, the majority < 2 years old, and 11 (78%) were girls. Of the 14 patients 8 (57.1%) had normal CA, 3 (21.4%) had occult CA dilatation and 3 (21.4%) had definite CA dilatation. When present, CA dilatation was detected within the first 8 days of presentation. Eleven (78%) patients presented with acute onset features and the remaining 3 presented with subacute characteristics. There was no correlation between CA involvement and the intensity of LV dysfunction however (p = 0.84).
Conclusion: Patients with viral myocarditis can present CA dilatation during the acute phase of the illness. This finding should be taken into account when diagnosing patients with incomplete KD on the basis of the CA involvement as the two illnesses may present with similar features.