PCR-based diagnosis of cytomegaloviruses in paraffin-embedded heart tissue in cases of suspected sudden infant death syndrome (SIDS)

[Lethal lymphocytic myocarditis-an underestimated diagnosis in infancy and childhood?]

In the past, histological diagnosis of (post-)viral myocarditis was based on the so-called Dallas criteria, which have been criticized because of high interobserver variability and sampling error. Immunohistochemical qualification and quantification of interstitial intramyocardial leucocytes was established and standard values concerning adults were published. Fatal casualties due to a viral myocarditis are rare as far as babies and children are concerned (sudden unexpected death in infancy; SUDI). Cases of sudden unexpected death in the first year of life are frequently regarded as sudden infant death syndrome (SIDS). To diagnose myocarditis when there are only single focal lymphocytic infiltrates in the myocardium, the number of samples taken by autopsy is relevant. But even in babies, immunohistochemical qualification and quantification of interstitial lymphocytes and macrophages can lead to standard values allowing diagnosis of myocarditis. Depending on the course of a viral infection, molecular pathological detection of viral genome in the myocardium is possible to support the diagnosis. Using the mentioned methods gradually, there are more cases of suspected SIDS, which are in fact cases of virus-induced myocarditis as cause of death. Primary enteroviruses (coxsackie viruses) and adenoviruses were found but also Epstein-Barr virus and PVB-19.

Cytomegalovirus-induced pneumonia and myocarditis in three cases of suspected sudden infant death syndrome (SIDS): Diagnosis by immunohistochemical techniques and molecularpathologic methods

Immunohistochemical and molecularpathologic techniques have improved the diagnosis of myocarditis as compared with conventional histologic staining methods done according to the Dallas criteria. Additionally, immunohistochemistry and in situ-hybridization are able to demonstrate viral infection, e.g. cytomegaloviruses in salivary glands and lungs, locations both known to be involved in cytomegalovirusinfection. However, in many cases of proved cytomegalovirusinfection the cause of death remains unclear. We report on three children younger than 1-year of age, who died suddenly without prodromal symptoms. Their deaths were attributed to SIDS (sudden infant death syndrome). In situ-hybridization, immunohistochemical (LCA, CD45R0, CD68, MHC-class-II-molecules, E-selectine) and molecularpathologic investigations (PCR), however, suggested that death was caused by a cytomegalovirus-induced pneumonia or myocarditis. In the future, these methods should be used for investigating cases with suspicion of SIDS.