RESUMEN
Objective To determine the dynamic change of serum procalcitonin (PCT) level after traumatic brain injury and the rclated clinical significance.Methods Serum levels of PCT and adrenocorticotropic hormone (ATCH) in 137 patients with traumatic brain injury and 20 normal volunteers were measured by electrochemiluminescence assay.Correlation between serum PCT level and severity of traumatic brain injury was evaluated.Results Percentage of serum PCT level at low inflammatory-risk threshold detected from day 1 to day 14 after admission was descended from 80.3％ to 63.5％.Meanwhile,the percentage of serum PCT level at high inflammatory-risk threshold was a rising-fall-rising trend,but the percentages of serum PCT level at median and definite inflammatory-risk thresholds showed sustained increase from 13.9％ to 27.0％ and 0.7％ to 3.7％ separately.Based on the Glasgow Coma Scale (GCS),the dynamic change of serum PCT level demonstrated a distinct bimodal pattern in severe injury group,a gradual falling after rising mode in middle injury group which was significantly and positively correlated with GCS (r =0.463,P ＜ 0.05),and a rising-falling-slight rising tendency in minorinjury group.In addition,the GCS in each group only closely related to the positive detections of serum PCT level detected at days 3 and 7 (x2 =10.32,16.31 respectively P ＜ 0.01).Serum ATCH level at day 1 was far higher than that at day 14 in severe injury group and was significantly higher in severe injurygroup compared with minor and middle injury groups (P ＜ 0.01 or 0.05).Conclusions Positive serum PCT may be predictive of the traumatic brain injury and injury degree within 3-7 days after the injury.The dynamic change of serum PCT is associated with the specialized mechanism of traumatic brain injury and neuronendocrine response,and it may be a useful parameter to assess posttraumatic stress response and prognosis.