Sudden unexplained neonatal deaths

While several works have stressed the importance of post-mortem examination in every case of suspected sudden infant death syndrome (SIDS), little, if any, attention has been given to the mandatory need to apply the same investigational protocol also in all cases of sudden perinatal unexplained death, i.e., sudden neonatal unexplained death (SNUD) and sudden intrauterine unexplained death (SIUD). First of all, it should be underlined that there is a clear continuum between unexplained perinatal death and SIDS, as developmental abnormalities have been detected to be common to both, particularly in the cardiac conduction system and in the brainstem centers regulating vital functions. From the analysis of the conducting tissue, the following pathological findings emerged: accessory atrio-ventricular pathways, mostly Mahaim fibers, cartilaginous hypermetaplasia, abnormal resorptive degeneration, junctional islands, persistent fetal dispersion, hypoplasia of the cardiac conduction system or of the central fibrous body, splitting of the atrio-ventricular node or of the His bundle, and the Zahn node. All of these cardiac conduction findings may be isolated incidents, but they are frequently associated with autonomic nervous system alterations of the brainstem.