Head trauma and leucocytosis

Neutrophil-lymphocyte ratio as a predictor of outcome following traumatic brain injury: Systematic review and meta-analysis

Objectives

The neutrophil-to-lymphocyte ratio (NLR) is a simple and routinely performed hematological parameter; however, studies on NLR as a prognostic tool in traumatic brain injury (TBI) have yielded contradictory results.

Materials and Methods

This systematic review and meta-analysis was conducted according to the Preferred Reporting Items in the Systematic Review and Meta-Analysis guidelines 2020. Electronic databases of PubMed, Cochrane Library, Web of Science, and Scopus were searched. The population consisted of TBI patients in the absence of moderate and severe extracranial injury. Day 1 NLR was taken for the analysis. The outcomes evaluated were mortality and the Glasgow Outcome Scale (GOS). No restrictions were placed on the language, year and country of publication, and duration of follow-up. Animal studies were excluded from the study. Studies, where inadequate data were reported for the outcomes, were included in the qualitative synthesis but excluded from the quantitative synthesis. Study quality was evaluated using the Newcastle-Ottawa scale (NOS). The risk of bias was estimated using the Cochrane RoBANS risk of bias tool.

Results

We retrieved 7213 citations using the search strategy and 2097 citations were excluded based on the screening of the title and abstract. Full text was retrieved for 40 articles and subjected to the eligibility criteria, of which 28 were excluded from the study. Twelve studies were eligible for the synthesis of the systematic review while seven studies qualified for the meta-analysis. The median score of the articles was 8/9 as per NOS. The risk of selection bias was low in all the studies while the risk of detection bias was high in all except one study. Ten studies were conducted on adult patients, while two studies reported pediatric TBI. A meta-analysis for GOS showed that high NLR predicted unfavorable outcomes at ≥6 months with a mean difference of -5.18 (95% confidence interval: -10.04, -0.32); P = 0.04; heterogeneity (I2), being 98%. The effect estimates for NLR and mortality were a mean difference of -3.22 (95% confidence interval: -7.12, 0.68), P = 0.11, and an I2 of 85%. Meta-analysis for Area under the curve (AUC) receiver operating characteristic of the included studies showed good predictive power of NLR in predicting outcomes following TBI with AUC 0.706 (95% CI: 0.582-0.829).

Conclusion

A higher admission NLR predicts an increased mortality risk and unfavorable outcomes following TBI. However, future research will likely address the existing gaps.

Prognostic value of leukocytosis in pediatric traumatic brain injury

OBJECTIVE

The purpose of this study was to assess leukocytosis and its prognostic value in pediatric isolated traumatic brain injury (TBI).

METHODS

Two hundred one children with isolated TBI admitted to the authors' institution between June 2006 and June 2018 were prospectively followed and their data retrospectively analyzed. Initial blood leukocyte count (i.e., white cell count [WCC]), Glasgow Coma Scale (GCS) score, CT scans, duration of hospital stay, and Pediatric Cerebral Performance Category Scale (PCPCS) scores were analyzed.

RESULTS

The mean age was 4.2 years (range 0.2-16 years). Seventy-four, 70, and 57 patients had severe (GCS score 3-8), moderate (GCS score 9-13), and mild (GCS score 14-15) TBI, respectively, with associated WCC of 20, 15.9, and 10.7 × 109/L and neutrophil counts of 15.6, 11.3, and 6.1 × 109/L, respectively (p < 0.01). Higher WCC and neutrophil counts were demonstrated in patients with increased intracranial mass effect on CT, longer hospital stay, and worse 6-month PCPCS score (p < 0.05). Multivariate regression revealed a cutoff leukocyte count of 16.1 × 109/L, neutrophil count of 11.9 × 109/L, and neutrophil-to-lymphocyte ratio (NLR) of 5.2, above which length of hospital stay and PCPCS scores were less favorable. Furthermore, NLR was the second most important independent risk factor for a poor outcome (after GCS score). The IMPACT (International Mission for Prognosis and Analysis of Clinical Trials in TBI) adult TBI prediction model applied to this pediatric cohort demonstrated increased accuracy when WCC was incorporated as a risk factor.

CONCLUSIONS

In the largest and first prospective study of isolated pediatric head injury to date, the authors have demonstrated that WCC > 16.1 × 109/L, neutrophil count > 11.9 × 109/L and NLR > 5.2 each have predictive value for lengthy hospital stay and poor PCPCS scores, and NLR is an independent risk factor for poor outcome. Incorporating the initial leukocyte count into TBI prediction models may improve prognostication.

Effectiveness of complete blood count parameters for predicting intracranial injury in children with minor head trauma

Objective: We aimed to investigate the relationship between trauma severity and platelet indices (PI) and white blood cell (WBC) count to identify traumatic brain injury (TBI) in children with minor head trauma (MHT). Materials and methods: This prospective study included children with acute isolated MHT who underwent head computed tomography (CT) based on Pediatric Emergency Care Research Network (PECARN) criteria. Mean platelet volume (MPV), platelet distribution width (PDW), MPV to platelet ratio (MPV/PL), MPV to white blood cell ratio (MPV/WBC), and MPV to Neutrophil ratio (MPV/Neu) were evaluated. Results: 86 children with MHT and 245 controls were included the study. WBC, Neu count, MPV, MPV/WBC, MPV/Neu and MPV/PI ratios were statistically different among patients with abnormal CT, patients with normal CT and healthy controls (p < 0.05). For predicting abbreviated injury score (AIS) > 1, the AUC values of WBC, neutrophil, MPV/WBC and MPV/Neu were 0.746, 0.739, 0.726 and 0.724, respectively. Conclusion: In children with MHT who underwent CT, WBC, Neu counts, MPV/WBC and MPV/Neu ratios may be helpful for predicting the severity of trauma in pediatric emergency department.

Capillary transit time heterogeneity and flow-metabolism coupling after traumatic brain injury

Most patients who die after traumatic brain injury (TBI) show evidence of ischemic brain damage. Nevertheless, it has proven difficult to demonstrate cerebral ischemia in TBI patients. After TBI, both global and localized changes in cerebral blood flow (CBF) are observed, depending on the extent of diffuse brain swelling and the size and location of contusions and hematoma. These changes vary considerably over time, with most TBI patients showing reduced CBF during the first 12 hours after injury, then hyperperfusion, and in some patients vasospasms before CBF eventually normalizes. This apparent neurovascular uncoupling has been ascribed to mitochondrial dysfunction, hindered oxygen diffusion into tissue, or microthrombosis. Capillary compression by astrocytic endfeet swelling is observed in biopsies acquired from TBI patients. In animal models, elevated intracranial pressure compresses capillaries, causing redistribution of capillary flows into patterns argued to cause functional shunting of oxygenated blood through the capillary bed. We used a biophysical model of oxygen transport in tissue to examine how capillary flow disturbances may contribute to the profound changes in CBF after TBI. The analysis suggests that elevated capillary transit time heterogeneity can cause critical reductions in oxygen availability in the absence of 'classic' ischemia. We discuss diagnostic and therapeutic consequences of these predictions.

Decrease in white blood cell counts after thiopentone barbiturate therapy for refractory intracranial hypertension: A common complication

Background:

Leucopenia has been reported after induction of thiopentone barbiturate therapy for refractory intracranial hypertension. However, the incidence and characterisitics are not well described.

Aims:

We performed a retrospective review to describe the incidence and characteristics of leucopenia after induction of thiopentone barbiturate therapy.

Setting and Design:

Our centre is a national referral centre for neurotrauma and surgery in a tertiary medical institution.

Materials and Methods:

We performed a retrospective review of all patients who received thiopentone barbiturate therapy for refractory intracranial hypertension during an 18 month period from January 2004 to June 2005 in our neurosurgical intensive care unit.

Statistical Analysis Used:

Statistical analysis was performed using SPSS version 15.0. All data are reported as mean ± standard deviation or median (interquartile range). The Chi square test was used to analyze categorical data and student t test done for comparison of means. For paired data, the paired t-test was used.

Results:

Thirty eight (80.9%) out of 47 patients developed a decrease in white blood cell (WBC) count after induction of thiopentone barbiturate coma. The mean decrease in WBC from baseline to the nadir was 6.4 × 10⁹/L (P < 0.001) and occurred 57 (3-147) h after induction. The mean nadir WBC was 8.6 ± 3.6 × 10⁹/L. Three (6.4%) patients were leucopenic, with a WBC count of 2.8, 3.1, and 3.6 × 10⁹/L. None of them were neutropenic. We did not find an association between decrease in WBC count and clinical diagnosis of infection. We did not find any association between possible risk factors such as admission GCS, maximum ICP prior to induction of barbiturate coma, APACHE II score, total duration and dose of thiopentone given, and decrease in WBC count.

Conclusions:

Decrease in WBC count is common, while development of leucopenia is rare after thiopentone barbiturate coma. Regular monitoring of WBC counts is recommended.

[Clinical relevance of leukocyte differential in patients with marked leukocytosis in the emergency room]

PURPOSE

We analyzed the characteristics of the leukocyte differential and the clinical outcome in patients admitted in an emergency department with marked leukocytosis greater than 20×10(9)G/L.

METHODS

We studied a case series of consecutive patients admitted in an emergency department. The medical records were retrospectively reviewed after patient discharge. Three groups were defined: patients with infectious disorders (group I), noninfectious disorders (group II), and trauma (group III). Admission in intensive care unit (ICU), consciousness impairment or death defined the subgroup S of high severity.

RESULTS

Groups I, II and III comprised, respectively, 150, 95 and 86 patients. The group I presented with higher temperature and neutrophilia (22,2±4.9 vs 20.9±4.0 and 21.1±3.9×10(9)G/L; P<0.001), and more profound eosinopenia (0.058±0.094 versus 0.098±0.170 and 0.092±0.104×10(9)G/L; P<0.001) and lymphopenia (1.16±0.98 vs 1.53±1.04 and 1.73±1.10×10(9)G/L; P<0.001) than the two other groups. Both neutrophilia and lymphopenia were independent predictors of infection by multivariate analysis. Frequencies of admission in ICU were, respectively, 8.7%, 40% and 43% (P<0.001). Leukocyte and neutrophil counts were significantly higher and basophil count significantly lower in subgroup S. Overall, 13.6% of the patients died and were characterized by basopenia.

CONCLUSION

Marked leukocytosis indicated severe illness. Lymphopenia, eosinopenia and temperature were significant predictors of infection. A more severe clinical course was correlated with higher neutrophilia and basopenia.

Leukocytosis as a predictor for non-infective mortality and morbidity

Leukocytosis (raised concentration of white cells in the blood) is commonly associated with infection or inflammation, but can occur in a wide variety of other conditions. Leukocytosis has also been linked with increased mortality and morbidity in a number of studies. We have systematically reviewed the relevant literature, which clearly demonstrates an association between leukocytosis and mortality-particularly due to cardiovascular or cerebrovascular causes. The mechanisms of this effect are uncertain but, when combined with other markers predictive of death, leukocytosis may contribute to modelling systems to predict in-patient mortality risk.

Peripheral blood picture following mild head trauma in children

BACKGROUND

The aim of the present study was to investigate changes in peripheral white blood cell, and differential counts following mild head trauma in a pediatric population.

METHODS

Fifty-one patients (mean age, 79 +/- 62 months) with mild head trauma (Glasgow Coma Scale [GCS] score 15) who were admitted to the emergency department, were studied. Two blood specimens were collected from each patient, one on arrival and one after 24 h at the emergency department. Complete blood count was performed using a hemocytometer and the absolute cell counts for each sample were calculated after examination of peripheral smear.

RESULTS

No patient developed any complication during the hospital stay or after discharge. Significant differences were found for white blood cell, neutrophil, and immature cell counts just after and 24 h after trauma (P = 0.047, 0.039 and 0.009, respectively).

CONCLUSIONS

Mild head trauma may cause an increase in white blood cell, neutrophil and band counts in children just after trauma. In a child with a mild head trauma, who is asymptomatic, with GCS score of 15 and absence of risk factors, and without clinical deterioration, complete blood cell count may be omitted from laboratory workup. But a prospective randomized study comparing mild head trauma patients with good and bad clinical outcome is needed to draw a definite conclusion.

Changes in circulating human endothelial progenitor cells after brain injury

Endothelial progenitor cells (EPCs) are mobilized from the bone marrow to blood circulation in response to tramatic or inflammatory stimulations. Once released, they actively seek and home to the sites of vascular injury to promote vascular repair. We monitored changes of EPC counts in peripheral blood of 29 patients with traumatic brain injury for up to 21 days. We showed that the levels of circulating EPCs within the first 48 h of injury were lower than control subjects, but increased over time-reaching plateau around 7 days post-injury at a level that was significantly higher than controls. The initial EPC reduction, which was severe in patients with severe injury Glasgow Coma Scale [GCS] < 12), differs from the acute increase in EPC counts found in patients with cardiovascular injury. The subsequent increase in circulating EPCs is primarily through bone marrow mobilization because the cells were stained predominantly for CD133, which labels immature EPCs, but not CD34 (which stains cell of endothelial lineage). The increase appeared earlier in male patients and was greater in those younger than 50 years of age. Changes in circulating EPCs during follow-up periods correlated with platelet, but not leukocyte counts. These results suggest that EPC mobilization following traumatic brain injury may take a different course compared to that associated with body or vascular injuries.

Hematologic abnormalities within the first week after acute isolated traumatic cervical spinal cord injury: a case-control cohort study

STUDY DESIGN

Case-control cohort study.

OBJECTIVE

To evaluate 1) the hematologic abnormalities within the first week following isolated acute cervical spine trauma or spinal cord injury (SCI); and 2) the influence of age, sex, and severity of SCI on these hematologic abnormalities.

SUMMARY OF BACKGROUND DATA

Given that autonomic nervous system has a critical role in the regulation of the hematopoietic system, we sought to evaluate the potential association between hematologic abnormalities within the first week posttrauma and the severity of SCI.

METHODS

All consecutive individuals with isolated acute cervical spine trauma admitted to our institution from 1998 to 2000 were reviewed. Exclusion criteria included preexisting medical comorbidities and polytrauma. The study population was divided into a SCI group and a control group (individuals with spine trauma without neurologic impairment). The SCI group was subdivided into patients with motor complete SCI (American Spinal Injury Association [ASIA] Grades A/B) and individuals with motor incomplete SCI (ASIA Grades C/D).

RESULTS

There were 21 SCI individuals (15 male, 6 female; ages 17-83 years; mean, 57 years) and 11 controls (6 male, 5 female; ages 18-75 years; mean, 41 years). When controlled for age, SCI individuals showed a significantly higher frequency of reduced hemoglobin concentration (RHC), leukocytosis, lymphopenia, and thrombocytopenia than controls within the first week posttrauma. Blood hemoglobin concentration, lymphocyte, and platelet counts in the SCI group were significant lower than the controls. The SCI group showed a significant higher leukocyte count than the controls. The degree of RHC and lymphopenia was significantly correlated with the severity of SCI.

CONCLUSION

Our results indicate that patients with isolated cervical SCI have significantly greater frequency of RHC, leukocytosis, lymphopenia, and thrombocytopenia than controls during the first week posttrauma. The degree of RHC and lymphopenia was significantly associated with the severity of SCI. While the mechanisms underlying these clinically important hematologic consequences of SCI remain undetermined, evidence from the literature suggests that acute autonomic denervation of the hematopoietic system could play a key role.

Classification and Regression Tree for Prediction of Outcome after Severe Head Injury Using Simple Clinical and Laboratory Variables

Many previous studies have constructed several predictive models for outcome after severe head injury, but these have often used expensive, time consuming, or highly specialized measurements. The goal of this study was to develop a simple, easy to use a model involving only variables that are rapidly and easily achievable in daily routine practice. To this end, a classification and regression tree (CART) technique was employed in the analysis of data from 345 patients with isolated severe brain injury who were admitted to Asclepeion General Hospital of Athens from January, 1993, to December, 2000. A total of 16 prognostic indicators were examined to predict neurological outcome at 6 months after head injury. Our results indicated that Glasgow Coma Scale was the best predictor of outcome. With regard to the other data, not only the most widely examined variables such as age, pupillary reactivity, or computed tomographic findings proved again to be strong predictors, but less commonly applied parameters, indirectly associated with brain damage, such as hyperglycemia and leukocytosis, were found to correlate significantly with prognosis too. The overall cross-validated predictive accuracy of CART model for these data was 86.84%, with a cross-validated relative error of 0.308. All variables included in this tree have been shown previously to be related to outcome. Methodologically, however, CART is quite different from the more commonly used statistical methods, with the primary benefit of illustrating the important prognostic variables as related to outcome. This technique may prove useful in developing new therapeutic strategies and approaches for patients with severe brain injury.

The blood leukocyte count and its prognostic significance in severe head injury

BACKGROUND

Head injury is associated with increased blood levels of catecholamines and cortisol. Catecholamines release neutrophil stores, and corticosteroids cause a decrease in the egress of neutrophils from the circulation. The acute-phase response is also characterized by a leukocytosis upon admission. Therefore, it is possible that an increase in the white blood cell (WBC) count might serve as an additional diagnostic and prognostic indicator in head injury.

METHODS

We prospectively studied 624 patients with severe, moderate, or minor head injury who were admitted to the neurosurgical department of Asclepeion Hospital in Athens between December 1997 and March 1999. In all cases, WBC count was obtained on admission to the emergency department. Factors that might influence WBC were excluded from this study.

RESULTS

Patients with severe head injury had significantly higher white blood cell counts than did those with moderate or minor injury (p < 0.001). Among the patients with severe head injury, a significant relationship was found between WBC counts and Glasgow Coma Scale score, pupillary reaction, and presence of subarachnoid hemorrhage (p < 0.001). In the same group of patients, WBC counts were significantly higher in those with an unfavorable outcome (p < 0.001). Multivariate analysis also showed that WBC counts were an independent predictor of outcome.

CONCLUSIONS

WBC counts on admission could serve as a significant parameter of severity of injury and as an additional predictor of neurological outcome in patients with severe head injury.

Brain IL-1beta increases neutrophil and decreases lymphocyte counts through stimulation of neuroimmune pathways

Leukocytosis after cerebral injury is well described and may participate in the generation of cerebral damage. However, the mechanisms of brain-induced leukocytosis are still speculative. Since it is known that proinflammatory cytokines are involved in neuroimmunomodulation and since others and we have demonstrated high cytokine levels in the cerebrospinal fluid following injury, we supposed that brain cytokines may also influence leukocyte counts. In order to evaluate this hypothesis, we established an animal model using continuous intracerebroventricular (i.c.v.), intrahypothalamic (i.h.), or intravenous infusion of the proinflammatory cytokines tumor necrosis factor (TNF)-alpha and IL-1beta. Controls received vehicle solution. With this experimental paradigm we could show that i.c.v. and i.h. infusion of IL-1beta but not TNF-alpha dramatically increased neutrophil counts, whereas lymphocytes dropped. Blocking the hypothalamic-pituitary-adrenal (HPA) axis by hypophysectomy abolished the neutrophilia, whereas the lymphopenia remained unchanged. Furthermore, application of the beta2-adrenoreceptor antagonist propranolol prevented the decrease of lymphocytes and diminished the neutrophilia. All parameters normalized within 48 h after termination of infusion. So, our results demonstrate that brain IL-1beta can modify blood leukocyte counts through stimulation of both the sympathetic nervous system (SNS) and the HPA axis.

Diagnosis and outcome of 100 consecutive patients with extreme granulocytic leukocytosis

PURPOSE

To determine the clinical features, causes, and prognostic significance of extreme leukocytosis in adults.

PATIENTS AND METHODS

Medical records of 100 consecutive patients who presented at the Minneapolis Veterans Affairs Medical Center between March 1993 and January 1994 with more than 25,000 leukocytes/microL blood and with more than 50% granulocytes were reviewed. Demographic, clinical, and outcome information was recorded, and a cause of extreme leukocytosis was sought in each case.

RESULTS

Extreme leukocytosis was attributed to infection in 48 cases, advanced malignancy in 13 cases, hemorrhage in 9 cases, glucocorticoids in 8 cases, and other causes in 22 cases. Four patients had previously diagnosed conditions resulting in chronic leukocytosis. Higher leukocyte counts were associated with malignancy (chi2 for trend=12.5, P <0.002). Fever was more common in patients with infection (weighted rate ratio=3.7, 95% Confidence interval [CI]=2.2 to 6.2). Mortality was high overall (31%), and was greater in patients with noninfectious diagnoses compared with infected patients, an association which persisted after stratification by leukocyte count (weighted rate ratio=2.5, 95% CI=1.2 to 4.9).

CONCLUSION

Clinicians should be aware that extreme leukocytosis with a predominance of granulocytes is associated with infection in only 48% of cases. The presence of fever increases the likelihood that infection is the cause. Mortality is high, particularly in patients without infection.

Early white blood cell dynamics after traumatic brain injury: effects on the cerebral microcirculation

Increasing clinical and experimental evidence suggests that traumatic brain injury (TBI) elicits an acute inflammatory response. In the present study we investigated whether white blood cells (WBC) are activated in the cerebral microcirculation early after TBI and whether WBC accumulation affects the posttraumatic cerebrovascular response. Twenty-four anesthetized rabbits had chronic cranial windows implanted 3 weeks before experimentation. Animals were divided into four experimental groups and were studied for 7 hours (groups I, IIa, and III) or 2 hours (group IIb). Intravital fluorescence videomicroscopy was used to visualize WBC (rhodamine 6G, intravenously), pial vessel diameters, and blood-brain barrier (BBB) integrity (Na+-fluorescein) at 6 hours (groups I, IIa, and III) or 1 hour (group IIb) after TBI. Group I (n = 5) consisted of sham-operated animals. Groups IIa (n = 7) and IIb (n = 5) received fluid-percussion injury at 1 hour. Group III (n = 7) received fluid-percussion injury and 1 mg/kg anti-adhesion monoclonal antibody (MoAb) "IB4" 5 minutes before injury. Venular WBC sticking, intracranial pressure (ICP), and arterial vessel diameters increased significantly for 6 hours after trauma. IB4 reduced WBC margination and prevented vasodilation. Intracranial pressure was not reduced by treatment with IB4. Blood-brain barrier damage occurred at 1 hour but not at 6 hours after TBI and was independent of WBC activation. This first report using intravital videomicroscopy to study the inflammatory response after TBI reveals upregulated interaction between WBC and cerebral endothelium that can be manipulated pharmacologically. White blood cell activation is associated with pial arteriolar vasodilation. White blood cells do not induce BBB breakdown less than 6 hours after TBI and do not contribute to posttraumatic ICP elevation. The role of WBC more than 6 hours after TBI should be investigated further.

Hypertonic/hyperoncotic saline attenuates microcirculatory disturbances after traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) induces an acute inflammatory response characterized by early recruitment of inflammatory cells (white blood cells). Rapid resuscitation of TBI with hypertonic saline/dextran (HS/DEX) yields promising results in clinical and experimental studies. The purpose of this paper was to test the hypothesis that HS/DEX exerts its effects in part through a modulation of the acute inflammatory response to TBI.

METHODS

Rabbits equipped with chronic cranial windows underwent fluid-percussion injury and were followed up for 6 hours. Intravital fluorescence videomicroscopy technique was used to visualize white blood cell trafficking and to measure pia vessel diameters and venular shear rates. Three groups were studied: sham (group I, n = 5), trauma (group II, n = 7), and trauma and 4 mL/kg 7.2% NaCl/10% dextran 60 IV over 5 minutes at 10 minutes after TBI (group III, n = 7).

RESULTS

TBI in groups II and III led to significant increases of intracranial pressure. Arteriolar diameters after trauma increased by 17 +/- 8% at 6 hours in group II. Infusion of HS/DEX completely prevented this secondary diameters increase. At 6 hours, the increase of "sticking" white blood cells in group III was reduced by approximately 90% compared with group II.

CONCLUSIONS

Whether the anti-inflammatory effect of HS/DEX plays a role in reducing delayed brain damage (> 6 hours after TBI) or other systemic complications of TBI arises as an important question and should be investigated further.