Cerebrospinal Fluid Glucose Concentration Research Articles

Development and validation of a new model for the early diagnosis of tuberculous meningitis in adults based on simple clinical and laboratory parameters

BackgroundThe differential diagnosis between tuberculous meningitis (TBM) and viral meningitis (VM) or bacterial meningitis (BM) remains challenging in clinical practice, particularly in resource-limited settings. This study aimed to establish a diagnostic model that can accurately and early distinguish TBM from both VM and BM in adults based on simple clinical and laboratory parameters.MethodsPatients diagnosed with TBM or non-TBM (VM or BM) between January 2012 and October 2021 were retrospectively enrolled from the General Hospital (derivation cohort) and Branch Hospital (validation cohort) of Ningxia Medical University. Demographic characteristics, clinical symptoms, concomitant diseases, and cerebrospinal fluid (CSF) parameters were collated. Univariable logistic analysis was performed in the derivation cohort to identify significant variables (P < 0.05). A multivariable logistic regression model was constructed using these variables. We verified the performance including discrimination, calibration, and applicability of the model in both derivation and validation cohorts.ResultsA total of 222 patients (70 TBM and 152 non-TBM [75 BM and 77 VM]) and 100 patients (32 TBM and 68 non-TBM [31 BM and 37 VM]) were enrolled as derivation and validation cohorts, respectively. The multivariable logistic regression model showed that disturbance of consciousness for > 5 days, weight loss > 5% of the original weight within 6 months, CSF lymphocyte ratio > 50%, CSF glucose concentration < 2.2 mmol/L, and secondary cerebral infarction were independently correlated with the diagnosis of TBM (P < 0.05). The nomogram model showed excellent discrimination (area under the curve 0.959 vs. 0.962) and great calibration (P-value in the Hosmer–Lemeshow test 0.128 vs. 0.863) in both derivation and validation cohorts. Clinical decision curve analysis showed that the model had good applicability in clinical practice and may benefit the entire population.ConclusionsThis multivariable diagnostic model may help clinicians in the early discrimination of TBM from VM and BM in adults based on simple clinical and laboratory parameters.

Cerebrospinal fluid analysis of metabolites is not correlated to microdialysis measurements in acute brain injured patients

BackgroundCerebral microdialysis (CMD) has become an established bedside monitoring modality but its implementation remains complex and costly and is therefore performed only in a few well-trained academic centers. This study investigated the relationship between cerebrospinal fluid (CSF) and CMD glucose and lactate concentrations. MethodsTwo centers retrospective study of prospectively collected data. Consecutive adult (>18 years) acutely brain injured patients admitted to the Intensive Care Unit between 2010 and 2021 were eligible if CSF and CMD glucose and lactate concentrations were concomitantly measured at least once. ResultsOf 113 patients being monitored with an external ventricular drainage and CMD, 49 patients (25 from Innsbruck and 24 from Brussels) were eligible for the final analysis, including a total of 96 measurements. Median CMD glucose and lactate concentrations were 1.15 (0.51–1.57) mmol/L and 3.44 (2.24–5.37) mmol/L, respectively; median CSF glucose and lactate concentrations were 4.67 (4.03–5.34) mmol/L and 3.40 (2.85–4.10) mmol/L, respectively. For the first measurements, no correlation between CSF and CMD glucose concentrations (R2 <0.01; p = 0.95) and CSF and CMD lactate concentrations (R2 =0.16; p = 0.09) was found. Considering all measurements, the repeated measure correlation analysis also showed no correlation for glucose (rrm = −0.01; 95% Confidence Intervals −0.306 to 0.281; p = 0.93) and lactate (rrm = −0.11; 95% Confidence Intervals −0.424 to 0.236; p = 0.55). ConclusionsIn this study including acute brain injured patients, no correlation between CSF and brain tissue measurements of glucose and lactate was observed. As such, CSF measurements of such metabolites cannot replace CMD findings.

Osmotic Minipump Implantation for Increasing Glucose Concentration in Mouse Cerebrospinal Fluid.

Diabetes increases the risk of cognitive decline and impairs brain function. Whether or not this relationship between high glucose and cognitive deficits is causal remains elusive. Moreover, whether these deficits are mediated by an increase in glucose levels in cerebrospinal fluid (CSF) and/or blood is also unclear. There are very few studies investigating the direct effects of high CSF glucose levels on central nervous system (CNS) function, especially on learning and memory, since current diabetes models are not sufficiently developed to address such research questions. This article describes a method to chronically increase CSF glucose levels for 4 weeks by continuously infusing glucose into the lateral ventricle using osmotic minipumps in mice. The protocol was validated by measuring glucose levels in CSF. This protocol increased CSF glucose levels to ~328 mg/dL after infusion of a 50% glucose solution at a 0.25 µL/h flow rate, compared to a CSF glucose concentration of ~56 mg/dL in mice that received artificial cerebrospinal fluid (aCSF). Furthermore, this protocol did not affect blood glucose levels. Therefore, this method can be used to determine the direct effects of high CSF glucose on brain function or a specific neural pathway independently of changes in blood glucose levels. Overall, the approach described here will facilitate the development of animal models for testing the role of high CSF glucose in mediating features of Alzheimer's disease and/or other neurodegenerative disorders associated with diabetes.

Cerebro-spinal fluid glucose and lactate concentrations changes in response to therapies in patIents with primary brain injury: the START-TRIP study

IntroductionAltered levels of cerebrospinal fluid (CSF) glucose and lactate concentrations are associated with poor outcomes in acute brain injury patients. However, no data on changes in such metabolites consequently to therapeutic interventions are available. The aim of the study was to assess CSF glucose-to-lactate ratio (CGLR) changes related to therapies aimed at reducing intracranial pressure (ICP).MethodsA multicentric prospective cohort study was conducted in 12 intensive care units (ICUs) from September 2017 to March 2022. Adult (> 18 years) patients admitted after an acute brain injury were included if an external ventricular drain (EVD) for intracranial pressure (ICP) monitoring was inserted within 24 h of admission. During the first 48–72 h from admission, CGLR was measured before and 2 h after any intervention aiming to reduce ICP (“intervention”). Patients with normal ICP were also sampled at the same time points and served as the “control” group.ResultsA total of 219 patients were included. In the intervention group (n = 115, 53%), ICP significantly decreased and CPP increased. After 2 h from the intervention, CGLR rose in both the intervention and control groups, although the magnitude was higher in the intervention than in the control group (20.2% vs 1.6%; p = 0.001). In a linear regression model adjusted for several confounders, therapies to manage ICP were independently associated with changes in CGLR. There was a weak inverse correlation between changes in ICP and CGRL in the intervention group.ConclusionsIn this study, CGLR significantly changed over time, regardless of the study group. However, these effects were more significant in those patients receiving interventions to reduce ICP.

Comparison of Suspected and Confirmed Internal External Ventricular Drain-Related Infections: A Prospective Multicenter United Kingdom Observational Study.

BackgroundDiagnosis of internal external ventricular drain (EVD)-related infections (iERI) is an area of diagnostic difficulty. Empiric treatment is often initiated on clinical suspicion. There is limited guidance around antimicrobial management of confirmed versus suspected iERI.MethodsData on patients requiring EVD insertion were collected from 21 neurosurgical units in the United Kingdom from 2014 to 2015. Confirmed iERI was defined as clinical suspicion of infection with positive cerebrospinal fluid (CSF) culture and/or Gram stain. Cerebrospinal fluid, blood, and clinical parameters and antimicrobial management were compared between the 2 groups. Mortality and Modified Rankin Scores were compared at 30 days post-EVD insertion.ResultsInternal EVD-related infection was suspected after 46 of 495 EVD insertions (9.3%), more common after an emergency insertion. Twenty-six of 46 were confirmed iERIs, mostly due to Staphylococci (16 of 26). When confirmed and suspected infections were compared, there were no differences in CSF white cell counts or glucose concentrations, nor peripheral blood white cell counts or C-reactive protein concentrations. The incidence of fever, meningism, and seizures was also similar, although altered consciousness was more common in people with confirmed iERI. Broad-spectrum antimicrobial usage was prevalent in both groups with no difference in median duration of therapy (10 days [interquartile range {IQR}, 7–24.5] for confirmed cases and 9.5 days [IQR, 5.75–14] for suspected, P = 0.3). Despite comparable baseline characteristics, suspected iERI was associated with lower mortality and better neurological outcomes.ConclusionsSuspected iERI could represent sterile inflammation or lower bacterial load leading to false-negative cultures. There is a need for improved microbiology diagnostics and biomarkers of bacterial infection to permit accurate discrimination and improve antimicrobial stewardship.

Exploring the Factors Affecting the Transferability of Vancomycin to Cerebrospinal Fluid in Postoperative Neurosurgical Patients with Bacterial Meningitis.

Vancomycin (VCM) is a standard treatment for bacterial meningitis. However, little is known about the transferability of VCM to cerebrospinal fluid (CSF), thus evidence of the transferability of VCM to CSF during bacterial meningitis is needed. In this study, we evaluated the concentration of VCM in the plasma and CSF of postoperative neurosurgical patients with bacterial meningitis and evaluated the factors that affect the transferability of VCM to CSF. The concentrations of VCM in plasma (trough) and CSF were determined in eight patients (four males and four females) with bacterial meningitis who were treated with VCM using HPLC. The ratio of the VCM concentrations in CSF/plasma was also calculated by estimating the blood VCM concentration at the same time as the VCM concentration in CSF was measured. The results showed that the VCM concentration in CSF was 0.9-12.7 µg/mL and the CSF/plasma VCM concentration ratio was 0.02-0.62. We examined the effect of drainage on the transferability of VCM to CSF, which showed that the VCM concentration in CSF and the CSF/plasma VCM concentration ratio were significantly higher in patients not undergoing drainage than in patients who were undergoing drainage. The CSF protein and glucose concentrations, which are diagnostic indicators of meningitis, were positively correlated with the VCM concentration in CSF and the CSF/plasma VCM concentration ratio. Thus, VCM transferability to CSF may be affected by changes in the status of the blood-brain barrier and blood-cerebrospinal fluid barrier due to drainage or meningitis.

Prevalence and outcome of bacterial meningitis among children of less than 10 years along the Kilombero valley in Morogoro, Tanzania

INTRODUCTION: Bacterial meningitis is among the febrile, lethal and life-threatening diseases in neonates and children under 10 years, especially in low-income countries. The study determined the prevalence and outcome of the disease among neonates, infants and children less than 10 years admitted at St. Francis Referral Hospital.METHODS: A hospital-based study was carried out among 856 children less than ten years, with or without fever for 10 months; clinical and laboratory records were reviewed. Data analysis was done using Chi-square and independent t-test to establish the odds ratio of acquiring the disease.RESULTS: Out of 856 records of children with fever 656 had signs of meningitis, 71 children underwent lumbar puncture where 49.3% and 50.7% were female and male respectively; Aged 0 - 2 years (47.9%), 3 – 5 years (19.7%) and 6 – 10 years (32.4%). 62% of the patients had neurological signs, 56.3% had &gt;45mmol/dl CSF (cerebrospinal fluid) glucose concentration and 85.9% had &gt;50mg/dl of the CSF protein concentration. Escherichia coli, Klebsiella pneumoniae, Haemophilus influenzae and Neisseria meningitides were mostly isolated from the CSF samples at the hospital. Location (OR) = 3.1; p = 0.0017), parity of the mother (OR = 3.8; p = 0.008), Neurological signs (OR = 4.5; p = 0.001) and elevated CSF protein (OR = 4.5; p = 0.001) were the factors associated with bacterial meningitis infection among children.CONCLUSION: Meningitis is a life-threatening infection in children under 10 years. Thus, microbial isolation should be established in most hospitals to improve early case identification and reporting at health facilities and the national level.

Influences of protein levels on the cerebrospinal fluid distribution of ceftazidime & ceftriaxone in the cerebrospinal fluid of patients with inflamed meningitis

IntroductionCeftazidime and ceftriaxone are used to treat various gram-negative pathogens, such as Streptococcus pneumoniae and Pseudomonas aeruginosa, and have shown excellent therapeutic efficacy against bacterial meningitis. However, there is insufficient information on the pharmacokinetic characteristics of their cerebrospinal distribution. Here, we investigated the association of clinical laboratory data in cerebrospinal fluid with ceftazidime and ceftriaxone concentration in the cerebrospinal fluid of patients with inflamed meningitis. MethodsCerebrospinal fluid samples were collected from eight adult patients with inflamed meningitis who intravenously received either ceftazidime or ceftriaxone (ceftazidime: a total of 25 samples from three patients, ceftriaxone: a total of 12 samples from five patients). Total cell number, protein concentration, and glucose concentration in the cerebrospinal fluid were retrospectively collected from electronic medical charts. All ceftazidime and ceftriaxone concentrations in the cerebrospinal fluid were determined using high-performance liquid chromatography. ResultsBoth ceftazidime and ceftriaxone concentrations in cerebrospinal fluid correlated with protein concentration in cerebrospinal fluid; however, no significant correlation was observed in total cell number and glucose concentration in cerebrospinal fluid. ConclusionsThis is the first report on the relationship between the cerebrospinal distribution of these antibiotics and clinical laboratory data in cerebrospinal fluid of adult patients with meningitis.

Alteration in glucose metabolism in the brain associated with tamoxifen treatment: Study in postmenopausal animal model

Tamoxifen is an effective breast cancer therapy in postmenopausal women. However, it can induce hyperglycemia through different mechanisms, such as the impairment of mitochondrial metabolism. Quercetin, a flavonoid with antioxidant potential, has beneficial effects on tamoxifen-induced adverse effects. Therefore, this study aimed to (1) investigate glucose concentration in blood, cerebrospinal fluid, cerebellum, cortex, and hippocampus of tamoxifen-treated ovariectomized female rats, non-treated and treated with quercetin; and (2) establish the metabolic profile of these regions. For that purpose, ovariectomized female rats were divided into four groups: canola oil 1 mL/kg (CONT); tamoxifen 5 mg/kg (TAM); quercetin 22.5 mg/kg (QUER); and tamoxifen 5 mg/kg + quercetin 22.5 mg/kg (TAM + Q); and were treated for 14 days orally. Subsequently, glucose levels were measured in blood, cerebrospinal fluid, cerebellum, cortex, and hippocampus. Pyruvate and lactate concentrations were analyzed in the three brain regions. Tamoxifen-induced hyperglycemia significantly increased glucose concentrations in the cerebrospinal fluid, cortex, and hippocampus, as well as lactate production in the hippocampus. Quercetin significantly prevented the tamoxifen-induced increase in glucose concentrations in all analyzed samples. Besides, quercetin decreased cortical pyruvate production. The copper content decreased only in the hippocampus of group TAM + Q animals. In addition, it is important to highlight that this study also observed that fourteen days of tamoxifen treatment strongly affects brain glucose metabolism, potentially disrupting normal brain functions. Therefore, this drug might represent a risk factor for postmenopausal women undergoing chemoprevention. Meanwhile, quercetin represents a potential intervention to promote metabolic regulation of glucose in tamoxifen-treated women.

Erratum: Sensitivity and specificity of cerebrospinal fluid glucose measurement by an amperometric glucometer.

[No Abstract Available].

A novel approach with glass needle enclosed movable probe for in vivo real-time detection of glucose in cisternal cerebrospinal fluid

Abstract Persistent episodes of hyperglycaemia in diabetes leads to serious damage to nerve system (referred to as diabetic neuropathy), such as nerve conduction abnormalities, pain and allodynia, and impaired axonal regeneration. Real-time monitoring glucose in brain is of great significance in better understanding the pathophysiological mechanisms of hyperglycaemia related brain disorders. However, it has never been achieved in real-time in vivo detection of the rise of glucose concentration in cerebrospinal fluid (CSF) caused by an instant glucose intake, due to technical difficulties. Here, we introduced a novel electrochemical approach with glass needle enclosed movable glucose probe to in vivo detect glucose in cisternal CSF of mice. After the glass needle was punctured into cisterna magna of mouse by stereotactic guidance, the inner probe was inserted into the cisternal CSF to achieve the recording. By this approach, we successfully measured the amperometric signal corresponding to the intraperitoneal injection of glucose solution. Thus, a novel approach was developed to real-time detect the glucose in cisternal CSF of mice in vivo.

Cerebrospinal fluid assessment in dogs with spinal tumors and intervertebral disk herniation

The study presents a retrospective case study. This aim was to determine whether lactate, glucose and total protein in serum and cerebrospinal fluid (CSF) can be used as specific biochemical markers for rapid differential diagnosis between intervertebral disk herniation and spinal tumors. Canine blood (n=9) and cerebrospinal fluid (n=9) were collected for chemistry analysis in nine dogs divided into two groups: intervertebral disk herniation group (IVDHG) (n=6) and spinal tumor group (TG) (n=3). Absorption spectrophotometry was used for quantitative determination of the concentrations of lactate, glucose and total protein in serum and CSF. Lactate concentration in serum and CSF and glucose concentration in CSF were 40-60% higher in subjects in TG compared to the IVDHG group. Serum lactate concentrations in the IVDHG group were 60% lower than physiological values. The results indicate that elevated concentration of glucose, lactate and total proteins in CSF and serum are indicative of a tumor, while a decrease of serum lactate and other parameters within normal range indicate disk herniation.

Sensitivity and specificity of cerebrospinal fluid glucose measurement by an amperometric glucometer.

Objectives:To provide more data regarding the role of an amperometric glucometer in diagnosing meningitis.Methods:This is a prospective study conducted at the Pediatric and Neonatology Department, Qatif Central Hospital, Qatif, Saudi Arabia between March 2017 and September 2018. We measured glucose concentrations in cerebrospinal fluid (CSF) and blood using a central laboratory and amperometric glucometer (AG). We compared CSF/blood glucose ratios obtained in a central laboratory from clinical bedside examination with a glucometer, and calculated the sensitivity and specificity for detecting cases of meningitis.Results:A total of 101 patients with clinical suspicion of meningitis were recruited for CSF sampling. Of 101 CSF samples, 61 (60%) were suggestive of meningitis. Of 101 samples, 47 had hypoglycorrhachia identified by a standard laboratory, and 17% of them were also detected by AG. The correlation between CSF/blood glucose by AG and laboratory ratios was substantial (r=0.894, p<0.01, 95% CI: 0.805-0.983). The AG sensitivity was 100% and specificity was 55% in pediatric cases, while in neonates the sensitivity was 86% and the specificity was 26%.Conclusion:Amperometric glucometers can be used to detect hypoglycorrhachia accurately. This point-of-care testing tool is easily accessible and can be used by health care providers for cases suspected of meningitis.

Increased Cerebrospinal Fluid Amyloid-β During Sleep Deprivation in Healthy Middle-Aged Adults Is Not Due to Stress or Circadian Disruption.

Concentrations of soluble amyloid-β (Aβ) oscillate with the sleep-wake cycle in the interstitial fluid of mice and cerebrospinal fluid (CSF) of humans. Further, the concentration of Aβ in CSF increases during sleep deprivation. Stress and disruption of the circadian clock are additional mechanisms hypothesized to increase CSF Aβ levels. Cortisol is a marker for stress and has an endogenous circadian rhythm. Other factors such as glucose and lactate have been associated with changes in sleep-wake activity and/or Aβ. In this exploratory study, we used samples collected in a previous study to examine how sleep deprivation affects Aβ, cortisol, lactate, and glucose in plasma and CSF from healthy middle-aged adults (N = 11). Eleven cognitively normal participants without evidence of sleep disturbance were randomized to sleep deprivation or normal sleep control. All participants were invited to repeat the study. Cortisol, lactate, glucose, and Aβ were measured in 2-h intervals over a 36-h period in both plasma and CSF. All concentrations were normalized to the mean prior to calculating mesor, amplitude, acrophase, and other parameters. One night of sleep deprivation increases the overnight concentration of Aβ in CSF approximately 10%, but does not significantly affect cortisol, lactate, or glucose concentrations in plasma or CSF between the sleep-deprived and control conditions. These data suggest that sleep deprivation-related changes in CSF Aβ are not mediated by stress or circadian disruption as measured by cortisol.

Development and verification of a discriminate algorithm for diagnosing post-neurosurgical bacterial meningitis-A multicenter observational study.

ObjectiveTo evaluate the diagnostic accuracy of cerebrospinal fluid (CSF)–based routine clinical examinations for post‐neurosurgical bacterial meningitis (PNBM) in multicenter post‐neurosurgical patients.MethodsThe diagnostic accuracies of routine examinations to distinguish between PNBM and post‐neurosurgical aseptic meningitis (PNAM) were evaluated by determining the values of the area under the curve (AUC) of the receiver operating characteristic curve in a retrospective analysis of post‐neurosurgical patients in four centers.ResultsAn algorithm was constructed using the logistic analysis as a classical method to maximize the capacity for differentiating the two classes by integrating the measurements of five variables. The AUC value of this algorithm was 0.907, which was significantly higher than those of individual routine blood/CSF examinations. The predicted value from 70 PNBM patients was greater than the cutoff value, and the diagnostic accuracy rate was 75.3%. The results of 181 patients with PNAM showed that 172 patients could be correctly identified with specificity of 95.3%, while the overall correctness rate of the algorithm was 88.6%.ConclusionsRoutine biomarkers such as CSF/blood glucose ratio (C/B‐Glu), CSF lactate (C‐Lac), CSF glucose concentration (C‐Glu), CSF leukocyte count (C‐Leu), and blood glucose concentration (B‐Glu) can be used for auxiliary diagnosis of PNBM. The multicenter retrospective research revealed that the combination of the five abovementioned biomarkers can effectively improve the efficacy of the PNBM diagnosis.

Developmental outcomes and prevalence of SLC2A1 variants in young infants with hypoglycorrhachia

IntroductionThe neurodevelopmental outcomes of young infants with hypoglycorrhachia that is comparable to glucose transporter 1 deficiency syndrome (GLUT1DS), i.e. cerebrospinal fluid (CSF) glucose ≤40 mg/dL and CSF lactate <2.2 mM without causes of secondary hypoglycorrhachia are unknown. This study investigated the developmental outcomes and possibility of GLUT1DS in infants with hypoglycorrhachia, or low CSF glucose concentration. Material and methods1655 neurologically asymptomatic infants aged <4 months had CSF examinations for fever workup from 2006 to 2016. Among the infants with normal CSF cell counts and without isolated pathogens, there were hypoglycorrhachia group who had CSF glucose levels that were comparable to GLUT1DS, and age- and gender-matched non-hypoglycorrhachia group. Both groups were at a mean age of 5.9 ± 2.4 years (ranged 1–10 years) at neurodevelopmental evaluation in 2017. Mutational analysis of solute-carrier-family 2, which facilitated the glucose transporter member 1 (SLC2A1) gene was performed. ResultsAmong the 722 infants with normal CSF cell counts and without isolated pathogens, 30 (4.2%) had hypoglycorrhachia that was comparable to GLUT1DS. In the 25 infants with hypoglycorrhachia available for follow-up, 4 (16%) had abnormal outcomes, of which 3 (12%) had the history of mixed-type developmental delay before age 6 and 1 (4%) had type 1 diabetes mellitus. In the non-hypoglycorrhachia control group (n = 50), 2 patients (4%) showed abnormal outcomes, both with the history of pure speech delay. The hypoglycorrhachia group had a higher rate of the history of mixed-type of developmental delay than the control group (12% vs. 0%, P = 0.034). No SLC2A1 pathogenic variants were observed in the hypoglycorrhachia group. ConclusionHypoglycorrhachia may be a potential biomarker for neurodevelopmental delay instead of for GLUT1DS in neurologically asymptomatic young infants.

053 GLUT-1 deficiency presenting as dopa-responsive dystonia: an atypical phenotype of a rare disease

IntroductionThe SLC2A1 gene encodes the glucose transporter GLUT1, responsible for normal glucose transport across the blood-brain barrier. Mutations in this gene have classically been associated with an epileptic encephalopathy referred to as GLUT-1 Deficiency Syndrome, which typically presents with early-onset refractory epilepsy, developmental delay and complex movement disorders.1 2 More recently, SLC2A1 variants have been identified in patients with paroxysmal exercise-induced dyskinesia (PED), with or without a history of epilepsy.3 4 Response to medication is typically poor; however, both seizures and dyskinesia may improve following implementation of a ketogenic diet.5 A single case of levodopa responsiveness has previously been described in a subject with SLC2A1 mutation and PED.5Methods and resultsWe describe a 47-year-old female with mild intellectual disability since childhood but no history of epilepsy, who developed episodic dystonia affecting the lower limbs in her early 20’s. A clinical diagnosis of dopa-responsive dystonia was made following a marked, sustained response to levodopa. There was no significant family history. In her 40’s she developed breakthrough dystonia with exertion and choreiform movements affecting the fingers and face. A subsequent dystonia panel identified a heterozygous variant c.[1199G&gt;T];[=] (p.Arg400Leu) in the SLC2A1 gene. Cerebrospinal fluid glucose concentration was low (2.0 mmol/L). She declined a trial of a ketogenic diet.SLC2A1 variants are associated with PED; however, response to levodopa has not been widely reported.ConclusionIt is becoming increasingly evident that the phenotypic presentations of GLUT1 deficiency are diverse, and SLC2A1 testing should be considered in a broader range of patients.ReferencesWang, D, Kranz-Eble P, De Vivo DK. Mutational analysis of GLUT1 (SLC2A1) in Glut-1 Deficiency Syndrome. Human Mutation 2001;16:224–231.Klepper J, Leiendecker B. GLUT1 deficiency syndrome – 2007 update. Developmental Medicine &amp; Child Neurology 2007;49:707–716.Schneider SA, Paisan-Ruiz C, Garcia-Gorostiaga I, Quinn NP, Weber YG, et al. GLUT1 gene mutations cause sporadic paroxysmal exercise-induced dyskinesias. Mov Disord 2009;24(11):1684–1696.Suls A, Dedeken P, Goffin K, Van Esch H, Dupont P. Paroxysmal exercise-induced dyskinesia and epilepsy is due to mutations in SLC2A1, endoding the glucose transporter GLUT1. Brain 2008;131:1831–1844.Baschieri F, Batla A, Erro R, Ganos C, Cordivari C, Bhatia KP. Paroxysmal exercise-induced dystonia due to GLUT-1 mutation can be responsive to levodopa: a case report. J Neurol 2014;261:615–616.

Glucose and Lactate Concentrations in Cerebrospinal Fluid After Traumatic Brain Injury.

Studies in which brain metabolism has been monitored using microdialysis have indicated decreases in cerebral glucose concentration and increases in lactate concentration in patients with traumatic brain injury (TBI). However, few data are available on glucose and lactate concentrations in the cerebrospinal fluid (CSF) of TBI patients. This study investigates the relationship between CSF glucose and lactate concentrations and outcomes after TBI. Consecutive adult (>18 y) TBI patients were admitted to our 35-bed medicosurgical between 2011 and 2014 and were included in the study if they met the following inclusion criteria: presence of an external ventricular drain (EVD) for intracranial pressure monitoring, daily analysis of CSF glucose and lactate concentrations for 4 consecutive days, and concomitant measurements of blood glucose/lactate concentrations. Neurological outcome was assessed at 3 months using the extended Glasgow Outcome Scale (GOS), and unfavorable outcome defined as a GOS 1 to 4. Of 151 TBI patients who had an EVD, 56 met the inclusion criteria. Most EVDs were placed on the day of intensive care unit admission, and maintained for 10 (interquartile range: 6 to 14) days. On day 1, there was a weak but significant correlation between blood and CSF glucose concentrations (R=0.07, P=0.04), and a greater correlation between blood and CSF lactate (R=0.32, P<0.001). In multivariable analysis, day 1 CSF glucose/lactate ratio was independently associated with mortality (odds ratio: 0.22, 95% confidence interval: 0.08-0.61; P=0.003), and day 1 CSF lactate concentration with unfavorable outcome (odds ratio: 4.86; 95% confidence interval: 1.86-12.67; P=0.001). Low CSF glucose/lactate ratio is observed in nonsurvivors after severe TBI and may have prognostic value.

Cerebrospinal Fluid Glucose and Lactate Levels After Subarachnoid Hemorrhage: A Multicenter Retrospective Study.

In patients with subarachnoid hemorrhage (SAH), abnormalities in glucose and lactate metabolism have been described using cerebral microdialysis. Glucose and lactate concentrations in cerebrospinal fluid (CSF) are more easily accessible, but scarce data are available in this setting. The aim of this study is to assess the relationship of CSF glucose and lactate with blood concentrations and with unfavorable neurological outcome after SAH. A retrospective cohort study was conducted in 5 European University intensive care units. Patients aged 18 years and above who were admitted after a nontraumatic SAH over a 4-year period (2011 to 2014) were included if they had an external ventricular drain placed, daily analysis of CSF including glucose (±lactate) concentrations for 1 to 4 consecutive days, and concomitant analysis of glucose and lactate concentrations in the arterial blood. A total of 144 patients were included in the final analysis (median age: 58 [49 to 66] y; male sex: 77/144). Median time from admission to external ventricular drain placement was 1 (0 to 3) day; median Glasgow Coma Scale on admission was 10 (7 to 13), and CT-scan Fisher scale was 4. A total of 81 (56%) patients had unfavorable neurological outcome at 3 months (Glasgow Outcome Scale ≤3). There was a weak correlation between blood and CSF glucose (r=0.07, P=0.007), and between blood and CSF lactate levels (r=0.58, P<0.001) on day 1, which were not influenced by insulin therapy. The presence of shock and low CSF glucose/lactate ratio were the only independent predictors of unfavorable outcome. CSF glucose and lactate levels poorly correlated with blood concentrations. Low CSF glucose/lactate ratio was associated with poor neurological outcome.

Rapid detection of bacterial meningitis using a point-of-care glucometer.

In case of acute bacterial meningitis, a decision on the need for intensive care admission should be made within the first hour. The aim of this study was to assess the ability of a point-of-care glucometer to determine abnormal cerebrospinal fluid (CSF) glucose concentration at the bedside that contributes toward bacterial meningitis diagnosis. We carried out a prospective study and simultaneously measured the glucose concentrations in CSF and blood using a central laboratory and a point-of-care glucometer. We compared CSF/blood glucose ratios obtained at the bedside with a glucometer versus those obtained by the central laboratory. We determined the performance characteristics of the CSF/blood glucose ratio provided by a glucometer to detect bacterial infection in the CSF immediately after CSF sampling. We screened 201 CSF collection procedures during the study period and included 172 samples for analysis. Acute bacterial meningitis was diagnosed in 17/172 (9.9%) of CSF samples. The median turnaround time for a point-of-care glucometer analysis was 5 (interquartile range 2-10) min versus 112 (interquartile range 86-154) min for the central laboratory (P<0.0001). The optimal cut-off of the CSF/blood glucose ratio calculated from a bedside glucometer was 0.46, with a sensitivity of 94.1% (95% confidence interval: 71.3-99.9%), a specificity of 91% (95% confidence interval: 85.3-95%), and a positive likelihood ratio of 10. A glucometer accurately detects an abnormal CSF/blood glucose ratio immediately after the lumbar puncture. This cheap point-of-care method has the potential to speed up the diagnostic process of patients with bacterial meningitis.