The authors from the Children’s Hospital of Pittsburgh present a review of biochemical markers of traumatic brain injury (TBI). Neuron specific enolase (NSE), S100B marker for astrocyte death, and myelin basic protein (MBP) levels were studied in 91 children with closed head injury of varying severity; 35 of these patients had suffered inflicted TBI. Control samples were obtained from children having blood drawn as part of routine well-child care or during treatment of acute, non-inflicted long bone fracture. The NSE was increased in 63% of children with TBI and inflicted TBI. S100B was increased in 37% of children with TBI and 41% of children with inflicted TBI. MBP was increased in 50% of patients with intracranial hemorrhage (ICH) and in none without ICH. Of the 35 children with inflicted TBI, 80% had increases in at least 1 of the 3 markers, and 35% had increases in all 3 markers. In the children with only 1 elevated marker, the NSE increase was noted in 50%, S100B in 28.6%, and MBP in 21.4%. This suggests that a panel of all 3 markers may represent the best serologic screening test for TBI.
Dr. Spivack has disclosed no financial relationships relevant to this commentary.
Approximately one-third of children who are ultimately diagnosed with inflicted TBI receive an alternative diagnosis initially; 10% of these children die of a subsequent inflicted injury.1 Children with a diagnostic delay resulting from an initial misdiagnosis may present with non-specific symptoms such as vomiting, irritability, and/or lethargy in the absence of visible head trauma, seizures, or coma. The authors examine the possible utility of biochemical markers in distinguishing children with unrecognized inflicted TBI.
The best-studied biochemical markers of neurotrauma are detected in cerebrospinal fluid (CSF). In general, neurotoxic (eg, glutamate, quinolinic acid), inflammatory (eg, ICAM-1, P-selectin, cytokines), and neuroprotective (eg, Bcl-2, adenosine) markers are increased in children with all forms of TBI. However, the neurotoxic and inflammatory markers are generally present in higher concentration in children with inflicted TBI, while the reverse is true for neuroprotective markers.2,3 It is not known if this is due to the mechanism of injury, to the young age of victims, or to a possible increase in secondary insults to the brain. Studies of these substances may ultimately increase our understanding of the mechanisms of long-term sequelae of closed head injury, but the difficulty in obtaining CSF in the outpatient setting makes them poor screening tools for identification of unrecognized TBI.
Three serum markers may represent better choices as screening tests. NSE and S100B can be measured using a rapid ELISA test which requires only small amounts of serum. The NSE serves as a marker of neuronal death, S100B as a marker of astrocyte death. The additional marker, MBP, appears to be specific for the presence of...