Articles: brain-injuries.
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Disturbed ionic and neurotransmitter homeostasis are now recognized to be probably the most important mechanisms contributing to the development of secondary brain swelling after traumatic brian injury (TBI). Evidence obtained from animal models indicates that posttraumatic neuronal excitation via excitatory amino acids leads to an increase in extracellular potassium, probably due to ion channel activation. The purpose of this study was therefore to measure dialysate potassium in severely head injured patients and to correlate these results with intracranial pressure (ICP), outcome, and also with the levels of dialysate glutamate, lactate, and cerebral blood flow (CBF) so as to determine the role of ischemia in this posttraumatic ionic dysfunction. ⋯ The simultaneous increase of potassium, together with dialysate glutamate and lactate, supports the hypothesis that glutamate induces ionic flux and consequently increases ICP due to astrocytic swelling. Reduced CBF was also significantly correlated with increased levels of dialysate potassium. This may be due to either cell swelling or altered potassium reactivity in cerebral blood vessels after trauma.
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In this retrospective study, the authors evaluated confounding risk factors, which are allegedly influential in causing unprovoked posttraumatic epilepsy, in 489 patients from the frontlines of the Iran-Iraq War. Four hundred eighty-nine patients were followed for 6 to154 months (mean 39.4 months, median 23 months), and important factors precipitating posttraumatic epilepsy were evaluated using uni- and multivariate regression analysis. One hundred fifty-seven (32%) of 489 patients became epileptic during the study period. ⋯ The results of multivariate analysis, on the other hand, indicated that the GOS score and motor deficit were of greater statistical importance (X2 = 35.24, p < 0.0001; and X2 = 7.1, p < 0.07, respectively). Factors that did have much statistically significant bearing on posttraumatic epilepsy were the projectile type, site of injury on the skull, patient age, number of affected lobes, related hemorrhagic complications, and retained metallic or bone fragments. Glasgow Outcome Scale score and focal motor neurological deficit are of particular importance in predicting posttraumatic epilepsy after missile head injury.
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Journal of neurosurgery · Jan 2000
No reduction in cerebral metabolism as a result of early moderate hyperventilation following severe traumatic brain injury.
Hyperventilation has been used for many years in the management of patients with traumatic brain injury (TBI). Concern has been raised that hyperventilation could lead to cerebral ischemia; these concerns have been magnified by reports of reduced cerebral blood flow (CBF) early after severe TBI. The authors tested the hypothesis that moderate hyperventilation induced early after TBI would not produce a reduction in CBF severe enough to cause cerebral energy failure (CBF that is insufficient to meet metabolic needs). ⋯ The authors conclude that early, brief, moderate hyperventilation does not impair global cerebral metabolism in patients with severe TBI and, thus, is unlikely to cause further neurological injury. Additional studies are needed to assess focal changes, the effects of more severe hyperventilation, and the effects of hyperventilation in the setting of increased ICP.
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Journal of neurotrauma · Jan 2000
Application of 2,3,5-triphenyltetrazolium chloride staining to evaluate injury volume after controlled cortical impact brain injury: role of brain edema in evolution of injury volume.
A reliable method for measuring injury volume after traumatic brain injury (TBI) is of great importance when studying pharmacological protective agents in the field of head trauma research. Utilization of 2,3,5-triphenyltetrazolium chloride (TTC) has gained extensive acceptance in stroke research and has recently been applied to injury volume measurement in the lateral fluid percussion model. The present study was undertaken to apply this method to the controlled cortical impact (CCI) model and to study the role of brain edema. ⋯ A statistically significant reduction of injury volume was observed after postinjury day 4. We also observed that due to the presence of brain edema absolute injury volume is more than corrected injury volume in the first 3 days after injury as opposed to injury volume at postinjury day 7. These results suggest that the measurement of injury volume with TTC staining should be corrected for brain edema in the CCI brain injury model.