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Traumatic brain injury (TBI) is an important cause of mortality and disability in children and teenagers. A particular feature of the neuropathology at post-mortem is brain swelling. The cause of the swelling in some cases is not known, while in others it is associated with traumatic axonal injury or hypoxia. Apolipoprotein E (APOE) 4 allele is known to be an important genetic determinant of outcome in children after TBI. We hypothesized a relationship between possession of APOE4 and diffuse traumatic brain swelling. A total of 165 cases aged between 2 and 19 years were identified from the department's tissue archive. APOE genotype was determined by polymerase chain reaction (PCR) in 106 cases. Bilateral swelling was present in 44 cases (11 with APOE4), unilateral swelling in 25 cases (7 with APOE4) and in 36 cases (9 with APOE4) there was no evidence of brain swelling. There was no significant relationship between possession of APOE4 and the presence of cerebral swelling (?2 = 0.09, df = 2, P = 0.96). The 95% confidence interval for difference in proportions with swelling in those with and without the APOE4 is ?19% to 22%. Thus, a significant relationship was not found between diffuse brain swelling and possession of APOE4, and in this cohort of patients there was an identifying cause of the brain swelling in all cases.

Epidemiological studies have identified a history of head injury as a risk factor for Alzheimer's disease. However, the neuropathological mechanism underlying this relationship is as yet unclear. Neuronal cytoskeletal changes in the form of neurofibrillary tangles and neuropil threads have recently been demonstrated in young men who had sustained repetitive head injury and subsequently died in their 20s. In addition, recent experimental studies have found accumulation of tau within neuronal somata and damaged axons following diffuse brain injury. We hypothesized that tau-immunoreactive tangles may be present in the brains of patients who died after a single acute blunt head injury. A total of 45 cases of fatal head injury were immunostained for tau. They comprised nine groups (n=5 for each group) separated by age (0-19 years, 20-50 years, 50+ years) and survival time (

Introduction: Previous studies have found that polymorphisms of the apolipoprotein E gene (APOE) influences the outcome from head injury, with possession of APOE e4 being associated with an unfavourable outcome (Teasdale et al. Lancet 1997; 350: 1069–1071). In this study we correlated the pathological features of traumatic brain injury with the presence or absence of APOE e4. Materials and methods: During the 13-year period 1987–99, 238 brains were examined from cases of traumatic brain injury (TBI) in the Department of Neuropathology, Glasgow. APOE genotype was determined by PCR. For each case a number of pathological features were recorded ‘blind’ to the APOE e4 status. Results: Of the 238 cases examined, 83 (35%) had the APOE e4 allele, while 155 (65%) did not. Possession of APOE e4 was associated with a greater incidence of severe hypoxic brain damage (e4+ 54%, e4– 42%) and with a greater incidence of moderate or severe contusion index (e4+ 42%, e4– 30%). No significant differences were noted between the other pathological features examined. Conclusions: Possession of APOE e4 is associated with a greater incidence of moderate/severe contusional injury and severe hypoxic brain damage in fatal cases of TBI. This may be relevant to the relatively poor outcome from TBI in patients with an APOE e4 allele identified in clinical studies.