Assessment of the Macrophage Marker Quinolinic Acid in Cerebrospinal Fluid after Pediatric Traumatic Brain Injury: Insight into the Timing and Severity of Injury in Child Abuse

This study measured quinolinic acid (QUIN), a macrophage-microglia derived neurotoxin, in the cerebrospinal fluid (CSF) of children after non-inflicted and inflicted traumatic brain injury (nTBI, iTBI), and correlated QUIN concentrations with age, mechanism of injury (nTBi vs. iTBI), Glasgow Coma Scale (GCS) score and 6-month Glasgow Outcome Score. One hundred fifty-two CSF samples were collected from 51 children with severe TBI (GCS ≤ 8). CSF was collected at the time an intraventricular catheter was placed and daily thereafter. QUIN concentration was measured by gas chromatography–mass spectroscopy. Patients ranged in age from 2 months to 16 years. Eleven children (22%) had iTBI. Initial and peak CSF QUIN concentrations were higher in patients with iTBI versus nTBI after adjusting for time after injury and GCS. Despite the lack of a history of trauma in 82% of children with iTBI, 100% had a peak QUIN concentration of >100 nM. There was a significant increase in the CSF concentrations of QUIN following severe nTBI and iTBI in children. Higher initial and peak QUIN concentrations after iTBI may be due to severity of injury, young age, and/or delay in seeking medical care, which allows for increased secondary injury.