Serum neuron-specific enolase, S100B, and myelin basic protein concentrations after inflicted and noninflicted traumatic brain injury in children

Object. Misdiagnosis of inflicted traumatic brain injury (iTBI) is common. Serum biomarkers may be able to assist in the detection of iTBIs that would otherwise be missed. The authors investigated whether serum concentrations of biomarkers were increased after noninflicted (n)TBI and iTBI in pediatric cases of varying severity. Methods. This prospective, case-control study involved 100 patients (56 with nTBI, 44 with iTBI) and 64 controls. Blood was collected in patients within 12 hours of injury; a subset had serial samples. A single sample was collected from controls. Serum neuron-specific enolase (NSE), S100B, and myelin basic protein concentrations were measured. Abnormal concentrations were defined using receiver-operator characteristic (ROC) curves. The sensitivity and specificity of initial NSE and S100B and peak myelin basic protein concentrations for identifying TBI at ROC curve-defined cutoffs were 71 and 64% (NSE), 77 and 72% (S100B), and 44 and 96% (myelin basic protein), respectively. Eighty-six percent of patients having suffered iTBI had one or more biomarkers increased, including 82% of children with iTBI and a Glasgow Coma Scale score of 15, and two children with iTBI who were initially misdiagnosed. Children with iTBI had a later peak concentration of all three biomarkers and were more likely to have increased myelin basic protein levels at admission compared with patients with nTBI. Conclusions. Serum NSE, S100B, or myelin basic protein are increased in the majority of children with acute nTBI and iTBI, including well-appearing children with iTBI in whom the diagnosis might otherwise have been missed. Differences in the time course of NSE, S100B, and myelin basic protein after nTBI and iTBI may provide insight into the pathophysiology of iTBI. These serum markers should be prospectively evaluated in a target population of infants.