BIOCHEMICAL MARKERS OF CEREBRAL INJURY IN PATIENTS WITH MINOR HEAD TRAUMA AND ETHANOL INTOXICATION

Objective: To determine whether biochemical markers can selectively id entify those intoxicated patients with presumed minor head injuries wh o are likely to have CT evidence of Intracranial injury. Methods: Pati ents presenting to the ED with simultaneous presumed minor head trauma and ethanol intoxication were prospectively entered into this cross-s ectional study. Following phlebotomy, all patients received cranial CT . Associations between the presence of an abnormal CT scan for injury and serum levels of the following biochemical markers were sought: ser um catecholamines, creatine kinase-brain band (CK-BB), and serum amyla se. Serum levels are reported as mean +/- SEM. Results: Nine of the 10 7 patients (8.4%; 95% CI 3.9-15.4%) had evidence of intracranial injur y on CT. Mean serum CK-BB (16.1 +/- 3.7 vs 13.2 +/- 9.6 ng/mL), serum norepinephrine (913 +/- 117 vs 1,089 +/- 76 pg/mL), and serum amylase (64.9 +/- 14.8 vs 84 +/- 4.7 U/L) levels were not significantly differ ent in patients with and without CT evidence of intracranial injury, r espectively. Mean serum epinephrine (298 +/- 54 vs 167 +/- 18 pg/mL; p = 0.03) and serum dopamine (218 +/- 50 vs 130 +/- 9 pg/mL; p = 0.014) levels were significantly elevated in the group with intracranial inj ury on CT. A threshold level of serum dopamine greater than or equal t o 140 pg/mL yields a sensitivity of 89% (95% CI 52-100%) and a specifi city of 80% (95% CI 70-87%) for CT-evident injury. A threshold level o f serum epinephrine greater than or equal to 218 pg/mL yields a sensit ivity of 89% (95% CI 52-100%) and a specificity of 80% (95% CI 70-87%) for CT-evident injury. Conclusion: Elevated serum epinephrine and dop amine levels are associated with intracranial CT-evident injury for et hanol-intoxicated patients with presumed minor head injuries. The pote ntial use of these biochemical markers to guide a more selective appro ach to cranial CT scanning warrants further evaluation.