MEDICOLEGAL AND PATHOLOGICAL RELEVANCE OF IMMUNOHISTOCHEMICAL STAINS IN POSTMORTEM DIAGNOSIS OF DIFFUSE AXONAL INJURY (DAI)
Sami Abd El Sattar*, Nabil M. Khalil, Ahmed Abdelmoaty Mohamed, Assad Taher, Mohamed Mohye Elgamal.
Pathology Department* , Faculty of Medicine, Cairo University and *Forensic Medicine Department, MOI, Kuwait
In some head trauma cases, there is no obvious cause of death and no brain lesions detected despite the positive history and the short survival time. This study was conducted to evaluate the relevance of immuno-histochemistry for beta amyloid precursor protein (β-APP) in early detection of DAI. It was carried on 50 autopsy cases, 39 males and 11 females, aging between the 2nd to the 5th decades of life. Survival period was around 3 hours up to 4 weeks. The cause of head injury was determined. Complete autopsy was done. Selected brain tissue sections were prepared for examination with routine hematoxylin and eosin (H&E) stain, special stains; phosphotungstic acid hematoxylin (PTAH) and β-APP, neuro specific emulase (NSE), S100 protein, Synaptophysin, Glial Fibrillary Acid Protein (GFAP) immunohistochemistry. The brain was assessed grossly at two settings; "First look" before its removal from the skull and "second look" after 2 weeks of fixation in 10% buffered formalin. The results revealed that, there is no significant difference between age and sex, the causes of head injury were more common due to violent assaults, and motor vehicle accidents. Both H&E stain and PTAH stain can diagnose brain edema, DAI, as regards axonal swelling and damage after 6 hours post traumatic survival period. In early survival stage, (ß-APP) is highly significant for detection of axonal swelling as early as 3 hours survival period. GFAP stain has highly significant value in detecting the glial cells and gliosis in the late survival stage. The β-APP is a more sensitive and accurate method for early detection of DAI. It should be considered as an important technique that could provide valuable medico-legal evidences.
December 2011