Pathophysiology of sudden infant death syndrome

Abstract

There are many hypotheses for the cause of death in sudden infant death syndrome (SIDS). For many of these hypotheses, little or nothing is known about the relevant pathophysiological mechanisms. The use of the term sudden unexplained death in infants (SUDI) is becoming more common as it now seems evident that a number of infants formerly diagnosed as SIDS victims should now be diagnosed with “accidental suffocation,” homicide, cardiac arrhythmias, inborn errors of metabolism, or other disorders with differing pathophysiological mechanisms (Table 1). For example, even when death scene findings strongly support a diagnosis of accidental suffocation as the cause of death, it is believed by many that such infants may have brain stem defects that predispose them to suffocation. In such cases it is argued that these deaths are not completely explained by evidence from the death scene and postmortem examination, and so the use of the term SIDS still is appropriate. The following overview is divided into sections where at least some evidence of the pathophysiology has been documented as well as several more prominent theories for causal mechanism where evidence is still lacking.