Sudden infant death syndrome (SIDS) was first defined in the USA as: 'The sudden ... infant under one year of age which remains unexplained after a thorough ...
The Journal of Maternal–Fetal and Neonatal Medicine 2004;16(S2):41–42
Causes of sudden infant death syndrome from post-mortem examination G. Giordano Department of Pathology and Medicine of Laboratory, Section of Pathological Anatomy and Histology, Medical School of Parma University, Parma, Italy
Sudden infant death syndrome (SIDS) was first defined in the USA as: ‘The sudden death of an infant under one year of age which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history’. More recently, diverse studies have shown that some cases of SIDS can be explained, when an accurate post-mortem examination is performed. The primary objective of the present paper was to delineate possible causes of SIDS as derived from a review of autoptic studies reported in the literature. Key words: SIDS; POST-MORTEM EXAMINATION; ARCUATE NUCLEUS
INTRODUCTION Sudden infant death syndrome (SIDS), according to a US definition, was considered as: ‘The sudden death of an infant under one year of age which remains unexplained after a thorough case investigation, including performance of a complete autopsy, examination of the death scene, and review of the clinical history1. The primary objective of this study was to delineate possible causes of SIDS as derived from a review of autoptic studies reported in the literature. METHODS The review of the literature regarding SIDS was carried out using the Index Medicus journal database and searching for articles reporting SIDS and Sudden Infant Death Syndrome in their title. RESULTS AND DISCUSSION Recently, diverse studies have shown that some cases of SIDS can be explained when an accurate post-mortem examination is performed. Many researchers have suggested that SIDS is principally due to instantaneous interruption of cardiac and respiratory functions caused
by structural abnormalities of the cardiac conduction system, or abnormalities of the central and peripheral nervous systems. Abnormalities of the cardiac conduction system, demonstrated on gross examination, include neoplasm2 and subendocardial hemorrhage near the atrioventricular node3. Those observed histologically are structural alterations found on serial sections4, or microscopic polycystic tumors of the atrioventricular node3. It is suggested that the SIDS in these cases is caused by hemodynamic and conductive abnormalities. Alterations of the central nervous system responsible for SIDS are clinically unsuspected malformations such as lobar holoprosencephaly, subependymal gray matter heterotopias and delayed myelination5. Other abnormalities of the central nervous system, identified in histological serial sections of the brain stem, include marked hypoplasia of the arcuate nucleus, which is an important structure for central respiratory control and blood pressure6. Discrete T-lymphocytic leptomeningitis of the ventral medullary surface can be another cause of sudden and unexpected infant death due to involvement of an alteration in the outer layer of the arcuate nucleus7. A
Correspondence: Dr G. Giordano, Dipartimento di Patologia e Medicina di Laboratorio, Sezione Anatomia ed Istologia Patologica, Via A. Gramsci, 14, 43100 Parma, Italy # 2004 Parthenon Publishing. A member of the Taylor & Francis Group DOI: 10.1080/14767050410001727189
Received January 2004 Revised February 2004 Accepted March 2004
Autopsy in SIDS
small hemangioendothelioma observed after histological examination in the medulla oblongata can be a rare, but possible, lesion responsible for SIDS8. Morphometric studies on serial sections of the aorticopulmonary paraganglia, revealing hyperplasia as an increase in their number or diameter, suggested that sudden death in infants could be due to abnormal chemoreceptor function, with altered respiratory control9. Other conditions that seem to play an important role among the causative factors of sudden infant death are abnormalities of the origin, route10 and number of coronary arteries11. The mechanism of death in these cases may be due to decreased myocardial perfusion with alterations of cardiac rhythm. Pancreatic adenomatous hyperplasia has also become recognized as a cause of SIDS, because this disorder results in a fatal evolution of hyperinsulinemic hypoglycemia12. Other conditions that seem to be responsible for SIDS are asymptomatic infections, demonstrated by the presence of an inflammatory infiltrate during histological examination13. CONCLUSIONS Morphological and functional abnormalities in the first year suggest that causative factors of SIDS are diverse. Therefore, during autoptic study, single organs should be thoroughly examined. It is indispensable that specialists, such as pathologists, pediatricians and neonatologists, should constitute a regional group, which provides, via a computerized network, a forum for revision and discussion of SIDS problems. This regional group for studying of SIDS could: first, provide technical information for a correct autopsy; and second, provide diagnostic opinions from expert pathologists. This interdisciplinary study group could gradually enlarge to become national and to involve internationally recognized specialists, so that all aspects of SIDS, including pathogenesis, etiology, epidemiology and morphological features, can be studied and known, with the aim of making it possible to prevent this dramatic condition, as has been done with other diseases.
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