Pathological considerations of sudden infant death syndrome.

The definition of sudden infant death syndrome (SIDS) states the necropsy examination fails to show a cause of death. Nevertheless, continuing pathologic investigation of the infant who dies suddenly and unexpectedly is of paramount importance in order to (1) establish a diagnosis of SIDS with certainty, (2) assist in delineating mechanisms of death in such circumstances, and (3) determine whether other entities, some of which are genetic, are present. In SIDS, the necropsy provides the positive finding of intrathoracic petechiae in a high percentage of cases. It is suggested these hemorrhages are an important clue to terminal upper airway obstruction in SIDS which may be a result of disordered neuroregulatory control of respiration during sleep by the brainstem, and the unique anatomy of the infant's pharynx and surrounding structures. The so-called 'hypoxic tissue markers' suggesting SIDS victims may have suffered prolonged or recurrent apnea have not been confirmed in more recent carefully controlled pathologic studies employing sophisticated methods of histometric analysis.