Effect of bacterial meningitis complicating severe head trauma upon brain microdialysis and cerebral perfusion.

INTRODUCTION: This article describes changes in regional cerebral perfusion and brain metabolism in a case of bacterial meningitis complicating severe traumatic brain injury. CASE REPORT: As part of clinical monitoring of patients with severe head injury, cerebral microdialysis was performed and extracellular concentration of glucose, lactate, glutamate, and pyruvate was determined. A thermal diffusion probe was used for bedside monitoring of cerebral blood flow. Acinetobacter meningitis complicated the clinical course on the seventh post-admission day and dramatically altered the neurochemistry. Microdialysate analysis showed glucose under the detection limit, lactate at moderately high levels, and a marked increase in glutamate and pyruvate levels. A reduction of cerebral perfusion was detected in the early phase of meningitis, probably secondary to vascular complications related to the inflammatory process. DISCUSSION: This case describes an emerging area of study and practice in patients with brain injury. It demonstrates how cerebral perfusion monitoring and study of brain metabolism can provide an early detection of secondary events that complicate severe head injury and can contribute to a better understanding of the complex pathogenetic mechanisms responsible for neuronal damage.