Blood Biomarkers for the Management of Mild Traumatic Brain Injury in Clinical Practice

BACKGROUND

Despite the use of validated guidelines in the management of mild traumatic brain injury (mTBI), processes to limit unnecessary brain scans are still not sufficient and need to be improved. The use of blood biomarkers represents a relevant adjunct to identify patients at risk for intracranial injury requiring computed tomography (CT) scan.

CONTENT

Biomarkers currently recommended in the management of mTBI in adults and children are discussed in this review. Protein S100 beta (S100B) is the best-documented blood biomarker due to its validation in large observational and interventional studies. Glial fibrillary acidic protein (GFAP) and ubiquitin carboxyterminal hydrolase L-1 (UCH-L1) have also recently demonstrated their usefulness in patients with mTBI. Preanalytical, analytical, and postanalytical performance are presented to aid in their interpretation in clinical practice. Finally, new perspectives on biomarkers and mTBI are discussed.

SUMMARY

In adults, the inclusion of S100B in Scandinavian and French guidelines has reduced the need for CT scans by at least 30%. S100B has significant potential as a diagnostic biomarker, but limitations include its rapid half-life, which requires blood collection within 3 h of trauma, and its lack of neurospecificity. In 2018, the FDA approved the use of combined determination of GFAP and UCH-L1 to aid in the assessment of mTBI. Since 2022, new French guidelines also recommend the determination of GFAP and UCH-L1 in order to target a larger number of patients (sampling within 12 h post-injury) and optimize the reduction of CT scans. In the future, new cut-offs related to age and promising new biomarkers are expected for both diagnostic and prognostic applications.

S100B, Actor and Biomarker of Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) accounts for approximately 80% of all TBI cases and is a growing source of morbidity and mortality worldwide. To improve the management of children and adults with mTBI, a series of candidate biomarkers have been investigated in recent years. In this context, the measurement of blood biomarkers in the acute phase after a traumatic event helps reduce unnecessary CT scans and hospitalizations. In athletes, improved management of sports-related concussions is also sought to ensure athletes' safety. S100B protein has emerged as the most widely studied and used biomarker for clinical decision making in patients with mTBI. In addition to its use as a diagnostic biomarker, S100B plays an active role in the molecular pathogenic processes accompanying acute brain injury. This review describes S100B protein as a diagnostic tool as well as a potential therapeutic target in patients with mTBI.

Biomarker S100B in plasma a screening tool for mild traumatic brain injury in an emergency department

INTRODUCTION

A computerized tomography (CT) scan is an effective test for detecting traumatic intracranial findings after mild traumatic brain injury (mTBI). However, a head CT is costly, and can only be performed in a hospital.

OBJECTIVE

To determine if the addition of plasma S100B to clinical guidelines could lead to a more selective scanning strategy without compromising safety.

METHODS

We conducted a single center prospective cohort study at the emergency department. Patients (≥16 years) who received head CT and had a blood draw were included. The primary outcome was the accuracy of plasma S100B to predict the presence of any traumatic intracranial lesion on head CT.

RESULTS

We included 495 patients, out of the 74 patients who had traumatic intracranial lesions, 5 patients had a plasma S100B level below the cutoff value of 0.105 ug/L. For the detection of traumatic intracranial injury, S100B had a sensitivity of 0.932 , a specificity of 0.157, a negative predictive value of 0.930, and a positive predictive value of 0.163.

CONCLUSIONS

Among patients undergoing guideline-based CT scan for mTBI, the use of S100B, would results in a further decrease (14.8%) of CT scans but at a cost of missed injury, without clinical consequence, on CT.

A Novel Blood Inflammatory Indicator for Predicting Deterioration Risk of Mild Traumatic Brain Injury

Mild traumatic brain injury (mTBI) has a relatively higher incidence in aging people due to walking problems. Cranial computed tomography and magnetic resonance imaging provide the standard diagnostic tool to identify intracranial complications in patients with mTBI. However, it is still necessary to further explore blood biomarkers for evaluating the deterioration risk at the early stage of mTBI to improve medical decision-making in the emergency department. The activation of the inflammatory response is one of the main pathological mechanisms leading to unfavorable outcomes of mTBI. As complete blood count (CBC) analysis is the most extensively used laboratory test in practice, we extracted clinical data of 994 patients with mTBI from two large clinical cohorts (MIMIC-IV and eICU-CRD) and selected inflammation-related indicators from CBC analysis to investigate their relationship with the deterioration after mTBI. The combinatorial indices neutrophil-to-lymphocyte ratio (NLR), red cell distribution width-to-platelet ratio (RPR), and NLR times RPR (NLTRP) were supposed to be potential risk predictors, and the data from the above cohorts were integratively analyzed using our previously reported method named MeDICS. We found that NLR, RPR, and NLTRP levels were higher among deteriorated patients than non-deteriorated patients with mTBI. Besides, high NLTRP was associated with increased deterioration risk, with the odds ratio increasing from NLTRP of 1–2 (2.69, 1.48–4.89) to > 2 (4.44, 1.51–13.08), using NLTRP of 0–1 as the reference. NLTRP had a moderately good prognostic performance with an area under the ROC curve of 0.7554 and a higher prediction value than both NLR and RPR, indicated by the integrated discrimination improvement index. The decision curve analysis also showed greater clinical benefits of NLTRP than NLR and RPR in a large range of threshold probabilities. Subgroup analysis further suggested that NLTRP is an independent risk factor for the deterioration after mTBI. In addition, in vivo experiments confirmed the association between NLTRP and neural/systemic inflammatory response after mTBI, which emphasized the importance of controlling inflammation in clinical treatment. Consequently, NLTRP is a promising biomarker for the deterioration risk of mTBI. It can be used in resource-limited settings, thus being proposed as a routinely available tool at all levels of the medical system.

S100B in cardiac surgery brain monitoring: friend or foe?

Recent advances in perioperative management of adult and pediatric patients requiring open heart surgery (OHS) and cardiopulmonary bypass (CPB) for cardiac and/or congenital heart diseases repair allowed a significant reduction in the mortality rate. Conversely morbidity rate pattern has a flat trend. Perioperative period is crucial since OHS and CPB are widely accepted as a deliberate hypoxic-ischemic reperfusion damage representing the cost to pay at a time when standard of care monitoring procedures can be silent or unavailable. In this respect, the measurement of neuro-biomarkers (NB), able to detect at early stage perioperative brain damage could be especially useful. In the last decade, among a series of NB, S100B protein has been investigated. After the first promising results, supporting the usefulness of the protein as predictor of short/long term adverse neurological outcome, the protein has been progressively abandoned due to a series of limitations. In the present review we offer an up-dated overview of the main S100B pros and cons in the peri-operative monitoring of adult and pediatric patients.

Blood biomarkers of mild traumatic brain injury: State of art

BACKGROUND

Mild traumatic brain injury (mTBI) is one of the most common causes of emergency department visits around the world. Up to 90% of injuries are classified as mTBI. Cranial computed tomography (CCT) is a standard diagnosis tool to identify intracranial complications in adults with mTBI. Alternatively, children can be admitted for inpatient observation with CCT scans performed only on those with clinical deterioration. The use of blood biomarkers is a supplementary tool for identifying patients at risk of intracerebral lesions who may need imaging.

METHOD

We realised a bibliographic state of art providing a contemporary clinical and laboratory framework for blood biomarker testing in mTBI management.

RESULTS

The S100B protein is the only biomarker that can be used today in the clinical routine for management of mTBI with appropriate evidence-based medicine. Due to its excellent negative predictive value, S100B protein is an alternative choice to CCT scanning for mTBI management with considered, consensual and pragmatic use. In this state of art, we propose points to help clinicians and clinical pathologists use serum S100B protein in the clinical routine. A state of art on the different biomarkers (GFAP, UCH-L1, NF [H or L], tau, H-FABP, SNTF, NSE, miRNAs, MBP) is also conducted. Some of these other biomarkers, used alone (GFAP, UCH-L1) or in combination (GFAP+H-FABP±S100B±IL10) can improve the specificity of S100B.

CONCLUSION

Using a bibliographic state of art, we highlighted the added values of the blood biomarkers for the clinical management of mTBI.

Interest of blood biomarkers to predict lesions in medical imaging in the context of mild traumatic brain injury

Mild traumatic brain injury (mTBI) is one of the common causes of emergency department visits around the world. Up to 90% of injuries are classified as mTBI. Cranial computed tomography (CCT) is a standard diagnostic tool for adults with mTBI. Alternatively, children can be admitted for inpatient observation with CCT scans performed only on those with clinical deterioration. The use of blood biomarkers is a supplementary tool for identifying patients at risk of intracerebral lesions who may need imaging. This review provides a contemporary clinical and laboratory framework for blood biomarker testing in mTBI management. The S100B protein is used routinely in the management of mTBI in Europe together with clinical guidelines. Due to its excellent negative predictive value, S100B protein is an alternative choice to CCT scanning for mTBI management under considered, consensual and pragmatic use. In this review, we propose points to help clinicians and clinical pathologists use serum S100B protein in the clinical routine. A review of the literature on the different biomarkers (GFAP, UCH-L1, NF [H or L], tau, H-FABP, SNTF, NSE, miRNAs, MBP, β trace protein) is also conducted. Some of these other blood biomarkers, used alone (GFAP, UCH-L1) or in combination (GFAP + H-FABP ± S100B ± IL10) can improve the specificity of S100B.