Neuromarkers as diagnostic adjuvant to cranial CT in closed traumatic brain injury patients admitted to ICU: A preliminary comparative study

Objectives
Evaluating the diagnostic and/or prognostic yield of serum levels of three neuromarkers, serum S100 protein, neuron-specific enolase (NSE) and Glial Fibrillary Acidic Protein (GFAP), in patients who were admitted to surgical intensive care unit (SICU) and had closed traumatic brain injury with suspicious presence of intracranial hematoma compared versus cranial CT (CCT) as a gold standard diagnostic modality.
Patients and methods
The study included 70 patients who had sustained a closed traumatic brain injury (TBI) requiring intensive care and/or surgical interference. All patients underwent clinical evaluation for all traumatized organs using Injury Severity Score (ISS) and concerning TBI Glasgow Coma Scale (GCS) score was recorded after non-surgical resuscitation. Then, all underwent CT scanning of the brain and patients with a surgically treatable mass underwent decompressive craniotomy, while patients free of hematoma or with minute-to-small hematoma not necessitating surgical interference were kept under observation. Venous blood samples were obtained from all enrolled patients at time of admission and patients who showed deterioration during conservative treatment gave second sample for ELISA estimation of serum S100 protein, NSE and GFAP.
Results
Forty-three patients had intracranial hematoma (Positive CCT); 26 patients underwent surgical interference, while the other 17 hematoma patients and 27 hematoma free patients (Negative CCT) were kept under observation. Of them 15 patients; 10 with hematoma and five who were hematoma free developed symptoms of increased ICP and follow-up CCT examination defined five cases required surgical interference with 66.7% rate for unnecessary follow-up CCT. Thirty-nine patients (55.7%) responded to conservative treatment and were discharged to the ward, while a total of 31 patients (44.3%) had surgical interference. Mean serum levels of studied parameters were significantly higher in all patients compared to controls with significantly higher levels in patients who had positive CCT compared to those who had negative CCT and in patients who required surgical interference compared to those managed conservatively. Patients who showed deterioration had significantly 2nd sample higher serum levels of S100 protein and GFAP, but non-significantly higher serum NSE levels compared to at admission levels. Percentage of increase of serum GFAP levels in follow-up sample obtained from patients who had positive CCT was significantly higher compared to the percentage of increase in serum S100 protein and NSE.
Conclusion
Estimation of serum levels of neuromarkers as adjuvant diagnostic and prognostic tools for closed TBI patients, but serum level of GFAP showed superior applicability and was more valid prognostic modality that could spare unnecessary CCT if applied as the percentage of change in comparison to at admission levels.