Cerebrospinal Fluid Monoamine Metabolites and Glucose Metabolism in Posttraumatic Aggression

Background: This pilot study was conducted to determine if aggressive, post brain-injured patients have abnormal glucose metabolism or abnormal CSF monoamine metabolite concentrations as compared with non-aggressive, post brain-injured controls. Methods: Subjects with a history of traumatic brain injury underwent a lumbar puncture and glucose tolerance test after a three-week medication wash-out period. Monoamine metabolite concentrations and glucose nadirs were compared between aggressive and control subjects. Results: There were no statistical differences between the aggressive (n = 4) and control (n = 6) group with respect to age (28.5 ± 15.7 versus 28.0 ± 10.8), weight (72.5 kg ± 14.1 versus 67.7 kg ± 10.1) or number of months since brain injury (31.8 ± 26.1 versus 33.3 ± 23.3). There were no significant differences between the two groups in glucose nadirs following oral glucose challenge or in levels of CSF monoamine metabolite concentrations of 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA), or 3-methoxy-4-hydroxyphenylglycol (MHPG), although a trend toward significance was noted between the MHPG groups (higher MHPG within aggressive group). Conclusions: The preliminary data suggest that glucose metabolism and CSF monoamine metabolite concentrations do not differ significantly from aggressive subjects to controls in persons with brain injury. Follow-up prospective studies with larger sample sizes are needed to evaluate these preliminary findings.