OBJECTIVETo study the histopathologic changes of primary brain stem injury and to investigate their significance in the diagnosis of primary brain stem injury.

METHODSSixty-five autopsy cases died of primary brain stem injury and other diseases were enrolled into this study. The cases were subdivided into brain stem injury group (n = 25) and control group (including 20 cases died of cardiovascular disease and 20 cases died of non-cardiovascular diseases). The brain stem tissue sections were stained with hematoxylin-eosin and silver impregnation techniques. Immunohisto chemical study for glial fibrillary acidic protein, neurofilament, amyloid-beta and myelin basic protein was carried out. The widest cross diameters of 10 axons highlighted by immunostaining were measured in each low power field (x 100) through light miscroscopy in all the cases studied.

RESULTSIn comparing with that of the control group, there were differences in the degree of contusion lesion, reactive astrocytosis, edema and pathologic changes of neuronal cells present in the brain stem injury group and was statistically significant (P < 0.05). The axons locating in the brain stem injury group showed a distinctive histology by the appearance of significantly larger diameters (P < 0.05).

CONCLUSIONSPrimary brain stem injury demonstrates certain distinctive histopathologic changes and measurement of axonal diameters provides an additional quantitative index useful in autopsy diagnosis.