[A proposal of essentials for forensic pathological diagnosis of sudden infant death syndrome (SIDS)].

There are many sudden unexpected infant death cases which are easily diagnosed as sudden infant death syndrome (SIDS) both with or without autopsy in Japan. A SIDS diagnosis may provide a cover for accidental or criminal death. SIDS should not be a convenient diagnostic box that shelters the cases of unexpected infant death which lack the necessary antemortem information to make the correct diagnosis. The authors consider that SIDS should be diagnosed according to the direction of the international definition of SIDS, and propose the following essentials for a forensic pathological diagnosis. 1) A thorough autopsy should be performed based on precise autopsy protocol, including not only histological observation, but also, if necessary, toxicological, bacteriological, viral and/or biochemical examinations. 2) The forensic pathologist should be provided with pertinent information regarding antemortem health status, past clinical history, social circumstances, death scene investigation, etc. In order to collect more precise information, the authors recommend using a questionnaire such as the example in this report to record information from the deceased's guardians. 3) Suspicion of accidental death or infanticide should be completely ruled out. SIDS should be diagnosed only after these three essentials have been satisfied. When there is even a slight suspicion of accidental death or infanticide, or when the forensic pathologist can not obtain pertinent information about the deceased, the causes and classification of the death should be diagnosed as unspecified or undetermined. That is, the causes and classification of the death are undetermined as to whether it is a natural or unnatural death. Furthermore, several warning flags indicating a possible SIDS diagnosis were proposed: a case found dead in a supine position, the existence of a foreign body in the respiratory tract or mild infectious findings. The authors also emphasize the physician's responsibility to report a case found dead or dying of unnatural or clinically unexplained causes to the police. This is the crucial first step in getting an accurate diagnosis of SIDS.