Quantitation of medullary astrogliosis in sudden infant death syndrome.

One of the few relatively consistent pathologic observations in sudden infant death syndrome (SIDS) is astrogliosis of the brain stem. Astrogliosis is a nonspecific reactive process and its cause in SIDS, although still uncertain, is postulated to be hypoxia-ischemia. In this study, the distribution of reactive astrocytes throughout the rostral-caudal extent of the medulla has been determined. Although astrogliosis was present throughout the length of the medulla, it reached a maximum at levels 50-75% of total length, with 0% at the pontomedullary junction. Counting every reactive astrocyte through serial sections of the medulla seems unwarranted in view of the nonspecificity of the astrocytic response. This report proposes a practical approach to the quantitation of reactive astrocytes in SIDS by examining a representative sample of medulla midway through its length.