Outbreak of Coxsackievirus B1 Myocarditis in Neonates
Abstract & Commentary
By Dean L. Winslow, MD, FACP, FIDSA, Chief, Division of AIDS Medicine, Santa Clara Valley Medical Center; Clinical Professor, Stanford University School of Medicine, is Associate Editor for Infectious Disease Alert.
Dr. Winslow serves as a consultant for Siemens Diagnostics, and is on the speaker's bureau for Boehringer-Ingelheim and GSK.
Synopsis: A cluster of severe Coxsackievirus B1 (CVB1) infection occurred in Chicago area neonates in 2007. Of the 10 cases identified all had severe myocarditis, one underwent cardiac transplantation and one died of left ventricular dysfunction.
Source: Verma NA, et al. Outbreak of life-threatening Coxsackievirus B1 myocarditis in neonates. Clin Infect Dis. 2009;49:759-763.
From June to November 2007, 10 neonates were hospitalized at Chicago's Northwestern University Children's Memorial Hospital. All patients had a diagnosis of Coxsackievirus infection confirmed by use of viral culture and/or reverse-transcriptase polymerase chain reaction (PCR). Enteroviral serotyping and genotyping of the isolates at the CDC showed that all eight patients, from whom isolates were available for analysis, were infected with closely related strains of CVB1; two other patients were infected with CVB1 and CVB, but these isolates were not characterized further. Seven of the patients were hospitalized in August and September. None of the 10 was related. Five infants were premature, and eight were delivered by cesarean section.
All 10 patients were moderately to severely ill and required admission to the NICU. Initial presenting signs and symptoms were nonspecific and included temperature abnormality, respiratory symptoms, cyanosis, poor feeding, jaundice, and seizures in some of the infants. Maternal illness was documented in six of 10 infants and other sick household contacts were noted for three of six infants. Age at onset of illness ranged from one hour to 12 days of age. Myocarditis was present in all 10 infants, as evidenced by abnormal EKG and echocardiography, frequent arrhythmias, elevated brain natriuretic peptide, and troponin levels. Seven patients had thrombocytopenia (platelets 3 65,000 cells/uL). Seven patients had evidence of hepatitis by serum transaminase elevation. CSF abnormalities, including aseptic meningitis, were common. All patients required intensive support; nine received vasopressors and eight required intubation and mechanical ventilation. Cardiac disease in the infants was severe, with one dying 10 days after presentation and another infant with severe LV dysfunction received a heart transplant at eight weeks of age. Five of eight patients required post-discharge cardiac medications, and only three recovered normal cardiac function by the time of discharge. Autopsy performed on the infant who died revealed lymphocyte infiltration of the myocardium with myocyte damage and necrosis; the culture of cardiac tissue grew CVB1. Examination of the explanted heart on the baby who underwent cardiac transplantation at five weeks revealed a large area of extensive fibrosis involving the LV wall and two areas of calcification and interstitial fibrosis with multinucleated giant cells. No active myocarditis was seen and molecular testing for CVB was negative.
Commentary
CVB1 became the predominant enterovirus in the United States in 2007. Phylogenetic analysis of the strains submitted to the CDC suggested a single genetic lineage. Other clusters of CVB1 infection in 2007 were observed in Los Angeles and in Alaska. At least 32 neonates in the United States have required intensive care; 27 had multiorgan involvement. The report of this cluster of cases of severe neonatal infection due to CVB1 likely represents the "tip of the iceberg" of a larger epidemic of CVB1 infection in the United States that year. Sadly, antiviral treatment with agents such as pleconaril (which has excellent activity in vitro vs. picornaviruses) has proved disappointing in severe enterovirus infections, and it is doubtful that it would have helped these ill neonates. Thus, treatment of this devastating syndrome remains supportive.
From June to November 2007, 10 neonates were hospitalized at Chicago's Northwestern University Children's Memorial Hospital.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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