RESUMEN
Sudden infant death syndrome is the term applied to the sudden death of an infant or young child that is unexpected by history and for which a thorough postmortem examination fails to demonstrate an adequate cause of death. It is widely believed that sudden infant death syndrome is not an expression of a single cause and effect, but rather a multifactorial phenomenon. This paper gives an overview of recent developments in sudden infant death syndrome research presenting the various hypotheses regarding sudden infant death. Functional disturbances in the brainstem and cervical spinal cord areas related to the neurophysiology of respiration may contribute to the clinical findings associated with sudden infant death syndrome. Parturitional factors, which include maternal (labor and delivery) and extrinsic factors (obstetrical procedures) have received attention. Work has also been done on the development of those neuroanatomical structures associated with respiration. It is postulated that human development progresses through stages with a critical period at 2-4 months. Immaturity of the brainstem and cervical cord is characterized, histologically, by the presence of reticular dendritic spines on the neurons as well as a proliferation of astrocytes and glial cells. Any process, whether genetic, biochemical, biomechanical or traumatic, that alters normal development of the respiratory control centers related to spinal constriction and compression following birth trauma may be contributory to sudden infant death syndrome.