Alterations in cerebral oxidative metabolism following traumatic brain injury.

BACKGROUND: Traumatic brain injury (TBI) generates regional alterations in cerebral metabolism, leading to the potential evolution of persistent metabolic dysfunction. In the case of penetrating, firearm-related TBI, the pathophysiological mechanisms underlying these acute-phase metabolic derangements are not entirely understood-hindering the potential effectiveness of therapeutic intervention. The use of cerebral microdialysis to monitor biochemical alterations that occur, post-TBI, provides critical insight into the events that perpetuate neurological deterioration.
METHODS: Cerebral microdialysis was used to monitor alterations in the brain tissue chemistry of a 22-year-old female patient who sustained a penetrating gunshot wound to the head. Extracellular glucose, lactate, pyruvate, and lactate pyruvate ratio (LPR) were monitored over the course of the first-week post-injury.
RESULTS: Analysis of the microdialysate revealed sustained elevations in LPR with peaks in excess of those seen in patients who have sustained permanent ischemic injury. This interval of persistently elevated LPR was followed by a spontaneous reduction of values, to levels below the defined threshold for metabolic crisis, over a period of several days.
CONCLUSIONS: Microdialysis studies may significantly improve the understanding of the metabolic alterations that occur in patients who sustain a variety of forms of neurotrauma. Ultimately, monitoring these variations in brain tissue chemistry will improve the insight into the neuropathological mechanisms underlying penetrating traumatic brain injury, and enhance the therapeutic approach of these patients.