Bulbo-spinal pathology and sudden respiratory infant death syndrome

The term Sudden Infant Death Syndrome is misleading since the illness is characterized by sudden death as a result of failure to take into account some specific symptoms and causes. It is important to analyse the different events that precede onset of the syndrome (the course of pregnancy, any drugs taken by the mother, etc.), histological slides of bulbo-mesencephalic sections of any foetuses miscarried before the current pregnancy, or infants who died of SIDS, the pathogenic mechanisms related to the sequence of histological features, and any possible pre-existing causes that can be lethal even some days after birth. Much research has focused on the prenatal, peri-partum and post-partum periods, examining the possibility that such deaths could have been caused by a long-lasting inhibition of the activity of the respiratory muscles. At the end of pregnancy, physiological apoptosis eliminates the surplus number and the power of the inhibitory interneurons, allowing the rhythms of the infant’s physiological respiration to start up. This apoptosis occurs as a result of fatigue of the mother during the expulsive period. It is enhanced by hypoxia, hypoglycaemia, stress, hypotension, allergic reactions and hyperthermia, and is decreased by prematurely induced delivery, deep narcosis, abuse of alcohol and neurotropic drugs. A different aetiological process underlies sudden death in infants and in young athletes previously considered healthy. Among the different aetiologies and genetic or acquired pathologies that can cause the sudden death of apparently healthy subjects, we have considered those regarding the specialist fields of the anaesthetist, the obstetrician and the paediatrician. In deceased foetuses and infants referred to our Centre (“Lino Rossi” Research Centre for he study and prevention of the unexpected perinatal and infant death, University of Milan), we have analysed histological changes in the motor neurons and in the inhibiting interneurons of the respiratory centres, and their connections with the respiratory muscles.