Screening of milk aspiration in 105 infant death cases by immunostaining with anti-human α-lactalbumin antibody

To determine the frequency and degree of milk aspiration in infant death cases, immunohistochemical examinations were performed on lung sections from 41 sudden death cases and 64 in-hospital death cases using anti-human α-lactalbumin antibody. Milk aspiration to some degree was detected in more than half of the sudden death cases and in about one-third of the in-hospital death cases. A semi-quantitative examination of the amount of aspirated milk was subsequently performed in the positive cases. The amount of aspirated milk in the sudden death cases was significantly higher than that in the in-hospital death cases. The frequency distribution of the amount of aspirated milk was similar in shape in both groups. In most cases, a very small amount of aspirated milk was detected. The aspirated milk was assumed to be a result of occasional gastroesophageal reflux or cardiopulmonary resuscitation. However, in five cases, much larger amounts of aspirated milk were found. In these cases, milk aspiration may have been an important part of the cause of death. We concluded that slight milk aspiration is not rare in infant death cases, and that in a few cases, the aspiration is lethal. An immunohistochemical screening test is available to perform a postmortem diagnosis in these cases.