Incidence of post-dural puncture headache in research volunteers

Lumbar Puncture Complications: A Review of Current Literature

PURPOSE OF REVIEW

This paper reviews the complications of lumbar puncture with a focus on post-dural puncture headache including pathophysiology, risk factors, prevention, and treatment.

RECENT FINDINGS

Recent research has focused on understanding the multifactorial mechanisms of post-dural puncture headache and improving prevention and treatment strategies. Small caliber, pencil-point type needles are encouraged to minimize the risk of post-dural puncture headaches, especially in populations that are at higher risk for complication. While new medications and procedures show promise in small cohorts, conservative medical management and epidural blood patch are still the first and second-line treatments for PDPH. Post-dural puncture headache is the most frequent complication of lumbar puncture. There are both modifiable and nonmodifiable risk factors to consider when performing this procedure. Conservative medical management and procedure-based therapies exist for when complications of lumbar puncture arise.

Serum metabolic signatures for Alzheimer's Disease reveal alterations in amino acid composition: a validation study

INTRODUCTION

Alzheimer's Disease (AD) is complex and novel approaches are urgently needed to aid in diagnosis. Blood is frequently used as a source for biomarkers; however, its complexity prevents proper detection. The analytical power of metabolomics, coupled with statistical tools, can assist in reducing this complexity.

OBJECTIVES

Thus, we sought to validate a previously proposed panel of metabolic blood-based biomarkers for AD and expand our understanding of the pathological mechanisms involved in AD that are reflected in the blood.

METHODS

In the validation cohort serum and plasma were collected from 25 AD patients and 25 healthy controls. Serum was analysed for metabolites using nuclear magnetic resonance (NMR) spectroscopy, while plasma was tested for markers of neuronal damage and AD hallmark proteins using single molecule array (SIMOA).

RESULTS

The diagnostic performance of the metabolite biomarker panel was confirmed using sparse-partial least squares discriminant analysis (sPLS-DA) with an area under the curve (AUC) of 0.73 (95% confidence interval: 0.59-0.87). Pyruvic acid and valine were consistently reduced in the discovery and validation cohorts. Pathway analysis of significantly altered metabolites in the validation set revealed that they are involved in branched-chain amino acids (BCAAs) and energy metabolism (glycolysis and gluconeogenesis). Additionally, strong positive correlations were observed for valine and isoleucine between cerebrospinal fluid p-tau and t-tau.

CONCLUSIONS

Our proposed panel of metabolites was successfully validated using a combined approach of NMR and sPLS-DA. It was discovered that cognitive-impairment-related metabolites belong to BCAAs and are involved in energy metabolism.

Incidence and associated factors of post-dural puncture headache among orthopaedic patients after spinal anesthesia: a prospective cohort study

Background

Post-dural puncture headache (PDPH) is one of a complication of spinal anaesthesia, influenced mostly by various factors including the patient's age, spinal needle size and design and sex. This headache can be severe and debilitating, preventing ambulation and limiting daily living activities.

Objective

This study assessed the incidence and associated factors of PDPH among patients who received spinal anaesthesia for orthopaedic procedures at the Debre Tabor Comprehensive Specialized Hospital from June to August 2022.

Methods

Prospective cohort study design was employed using Consecutive sampling method among patients who received spinal anaesthesia for orthopaedics procedure at Debre Tabor Comprehensive Specialized Hospital from June to August 2022. Data were collected by face to face interview and direct observation based on questionnaire. The data were entered to epidata 4.6 and analyzed by SPSS version 20 software. A total 95 patients aged 16-75 was participated in study. Those independent variable that were significant on binary logistic regression at P less than 0.2, were analyzed on multivariate regression, and considered significant association with PDPH at P value less than 0.05.

Result

Ninety-five study participants were included in our study of which 19 (20%) had developed PDPH. Among patients who develop PDPH; 9.5% of the patients reported moderate pain while 10.5% experience mild PDPH and 80% of patient has no pain. The BMI and age were found to have significant association with PDPH [(P value 0.018, adjusted odds ratio 8.738, 95% CI, 1.461-52.269) and (P value 0.011, adjusted odds ratio 12.146, 95% CI, 1.753-84.170)], respectively) to PDPH.

Conclusion and recommendation

The incidence of PDPH was found to be higher in Debre Tabor Comprehensive Specialized Hospital. The hospital management and the anaesthetists should minimize the magnitude of by strictly following different preventive strategies.

Paravertebral Cerebrospinal Fluid Exudation in Young Women with Postdural Puncture Headache: A Hypothetical Interpretation based on Anatomical Study on Intervertebral Foramen

Background Postdural puncture headache (PDPH) is defined as a prolonged orthostatic headache secondary to a lumbar puncture. The mechanism underlying this unpleasant complication and the reasons explaining its higher incidence in the young are not well understood. Here, we speculate on the mechanisms underlying PDPH based on spinal magnetic resonance imaging (MRI) in patients with PDPH and an anatomical study on the size of the intervertebral foramen.

Methods Brain and spinal MRI findings were examined in two young women with PDPH. The relationship between age and size of the intervertebral foramen on computed tomography was assessed in 25 female volunteers (22–89 years old) without spinal disease.

Results The causative interventions leading to PDPH were epidural anesthesia for painless delivery in a 28-year-old woman and lumbar puncture for examination of the cerebrospinal fluid (CSF) in a 17-year-old woman. These two patients developed severe orthostatic hypotension following the procedure. Brain MRI showed signs of intracranial hypotension, including subdural effusion, in one patient, but no abnormality in the other. Spinal MRI revealed an anterior shift of the spinal cord at the thoracic level and CSF exudation into the paravertebral space at the lumbar level. Treatment involving an epidural blood patch in one patient and strict bed rest with sufficient hydration in the second led to improvement of symptoms and reduction of paravertebral CSF exudation. The size of the intervertebral foramen at the L2–3 level in the 25 volunteers showed a decrease in an age-dependent manner (Spearman's rho −0.8751, p < 0.001).

Conclusion We suggest that CSF exudation from the epidural space of the vertebral canal to the paravertebral space through the intervertebral foramen, which is generally larger in the younger population, is the causative mechanism of PDPH.

Predicting AT(N) pathologies in Alzheimer's disease from blood-based proteomic data using neural networks

BACKGROUND AND OBJECTIVE

Blood-based biomarkers represent a promising approach to help identify early Alzheimer's disease (AD). Previous research has applied traditional machine learning (ML) to analyze plasma omics data and search for potential biomarkers, but the most modern ML methods based on deep learning has however been scarcely explored. In the current study, we aim to harness the power of state-of-the-art deep learning neural networks (NNs) to identify plasma proteins that predict amyloid, tau, and neurodegeneration (AT[N]) pathologies in AD.

METHODS

We measured 3,635 proteins using SOMAscan in 881 participants from the European Medical Information Framework for AD Multimodal Biomarker Discovery study (EMIF-AD MBD). Participants underwent measurements of brain amyloid β (Aβ) burden, phosphorylated tau (p-tau) burden, and total tau (t-tau) burden to determine their AT(N) statuses. We ranked proteins by their association with Aβ, p-tau, t-tau, and AT(N), and fed the top 100 proteins along with age and apolipoprotein E (APOE) status into NN classifiers as input features to predict these four outcomes relevant to AD. We compared NN performance of using proteins, age, and APOE genotype with performance of using age and APOE status alone to identify protein panels that optimally improved the prediction over these main risk factors. Proteins that improved the prediction for each outcome were aggregated and nominated for pathway enrichment and protein-protein interaction enrichment analysis.

RESULTS

Age and APOE alone predicted Aβ, p-tau, t-tau, and AT(N) burden with area under the curve (AUC) scores of 0.748, 0.662, 0.710, and 0.795. The addition of proteins significantly improved AUCs to 0.782, 0.674, 0.734, and 0.831, respectively. The identified proteins were enriched in five clusters of AD-associated pathways including human immunodeficiency virus 1 infection, p53 signaling pathway, and phosphoinositide-3-kinase-protein kinase B/Akt signaling pathway.

CONCLUSION

Combined with age and APOE genotype, the proteins identified have the potential to serve as blood-based biomarkers for AD and await validation in future studies. While the NNs did not achieve better scores than the support vector machine model used in our previous study, their performances were likely limited by small sample size.

Post-dural puncture headache: a prospective study on incidence, risk factors, and clinical characterization of 285 consecutive procedures

Background

Lumbar puncture (LP) is a common and relatively safe neurological procedure. It can be complicated by post-dural puncture headache (PDPH) after both diagnostic and therapeutic procedures. The aim of this study is to identify the incidence, risk factors and clinical characterization of PDPH in the inpatient setting of the main tertiary neurology hospital in Kuwait.

Methods

We conducted a prospective observational cohort study that included patients who were admitted to neurology department at Ibn Sina hospital, Kuwait, from January 1, 2019 to December 31, 2020, on whom, LP was performed for diagnostic and/or therapeutic reasons. Multivariate logistic regression analysis was performed to evaluate the association between PDPH and different clinical parameters.

Results

A total of 285 patients were included; 225 females (78.9%), mean age of 32.9 ± 11.7 years. PDPH was reported by 84 patients (29.5%), with mean headache onset of 1.7 ± 0.8 days, and mean duration of 2.4 ± 2.1 days. The commonest headache type was dull aching in 49 patients (58.3%). Headache severity was mild to moderate in 64 patients (76.2%), with mean NRS of 4.1 ± 0.9. Most PDPH (99.3%) resolved with conservative medical management, with only 2 patients (0.7%) requiring epidural blood patch. In multivariate logistic regression model, there was a statistically significant correlation between development of PDPH and young age (p = 0.001), female gender (p = 0 .001), low BMI (p < 0 .001), pre-LP headache (p = 0.001), history of previous PDPH (p = 0.001), and number of LP attempts (p < 0.001). PDPH was statistically significantly higher in patients with optic neuritis (p = 0.009), and cerebral venous thrombosis (p = 0.007), and lower in patients with peripheral neuropathy (p = 0.011) and spinal muscular atrophy (p = 0.042).

Conclusions

Findings from clinical practice in the main tertiary neurology hospital in Kuwait were in line with literature findings. Younger age, female gender, lower BMI, pre-procedural headache, previous history of PDPH, and number of LP attempts were found to be independent risk factors for developing PDPH. To our knowledge, this study represents the first comprehensive description of PDPH in a population from the Arabian Gulf Region.

The effects of cerebrospinal fluid (CSF) diversion on post-operative CSF leak following extended endoscopic anterior skull base surgery

There is a paucity of high quality evidence regarding the routine placement of lumbar drain (LD) in reducing post-operative (op) cerebrospinal fluid (CSF) leak after extended endoscopic trans-sphenoidal resection of anterior skull base lesions. In this study, we sought to compare the incidence of post-op CSF leak between patients with upfront LD insertion and those without it. This was a prospective randomized controlled trial conducted over a period of 5 years with patients undergoing extended endoscopic trans-sphenoidal surgery randomly assigned to either LD insertion at the time of surgery, or no LD placement. Thirty-eight patients with anterior skull base tumors were accrued from three tertiary hospitals of Melbourne. Post-op leak was confirmed by β2-transferrin-positive rhinorrhea, and/or worsening pneumocephalus on brain imaging. Skull base defect size and pedicled nasoseptal flap viability were assessed on post-op CT and MRI, respectively. There was no significant difference in post-op CSF leak incidence between the two subgroups (12.50% in LD arm vs. 9.10% in no LD arm). Patients with LD insertion however, demonstrated substantially raised complication rates, longer hospital lengths of stay and lower subjective quality of life measures at 12 months compared with those without LD. In conclusion, routine placement of LD at the time of surgery for extended anterior skull base trans-nasal approach did not reduce the risk of post-op CSF leak. Discretion is warranted when using LD as an adjunct due to its associated morbidities, prolonged hospital stay and adverse effect on patients' subjective outcome measures.

Detection of Glial Fibrillary Acidic Protein in Patient Plasma Using On-Chip Graphene Field-Effect Biosensors, in Comparison with ELISA and Single-Molecule Array

Glial fibrillary acidic protein (GFAP) is a discriminative blood biomarker for many neurological diseases, such as traumatic brain injury. Detection of GFAP in buffer solutions using biosensors has been demonstrated, but accurate quantification of GFAP in patient samples has not been reported, yet in urgent need. Herein, we demonstrate a robust on-chip graphene field-effect transistor (GFET) biosensing method for sensitive and ultrafast detection of GFAP in patient plasma. Patients with moderate–severe traumatic brain injuries, defined by the Mayo classification, are recruited to provide plasma samples. The binding of target GFAP with the specific antibodies that are conjugated on a monolayer GFET device triggers the shift of its Dirac point, and this signal change is correlated with the GFAP concentration in the patient plasma. The limit of detection (LOD) values of 20 fg/mL (400 aM) in buffer solution and 231 fg/mL (4 fM) in patient plasma have been achieved using this approach. In parallel, for the first time, we compare our results to the state-of-the-art single-molecule array (Simoa) technology and the classic enzyme-linked immunosorbent assay (ELISA) for reference. The GFET biosensor shows competitive LOD to Simoa (1.18 pg/mL) and faster sample-to-result time (<15 min), and also it is cheaper and more user-friendly. In comparison to ELISA, GFET offers advantages of total detection time, detection sensitivity, and simplicity. This GFET biosensing platform holds high promise for the point-of-care diagnosis and monitoring of traumatic brain injury in GP surgeries and patient homes.

Aminophylline for Prevention and/or Treatment of Post-Dural Puncture Headache: A Systematic Review and Meta-Analysis Study Protocol

Objectives

Post-dural Puncture Headache (PDPH) is prevalent among individuals undergoing lumbar punctures. The non-invasive effect of some drugs, such as aminophylline on PDPH has been investigated in several clinical studies. As there is no comprehensive systematic review and meta-analysis about the preventive and therapeutic effects of aminophylline on PDPH in the literature, the clinical effectiveness of this drug on the prevention and/or treatment of PDPH will be assessed in this study.

Methods

PubMed/MEDLINE, Embase, WoS (Clarivate Analytics), the Cochrane Central Register of Controlled Trials (CENTRAL), CINAHL Complete, Scopus, and Google Scholar as electronic databases will be precisely searched for clinical studies that assessed the effect of aminophylline on PDPH. Studies between 01-01-1980 and 30-06-2020 will be evaluated in this study, and there will not be any language restrictions. Contradictions between the reviewers within any phase of the study (screening, selecting, quality assessment, and data extraction) will be resolved by consensus; in case of unsolved disagreements, a third reviewer will eventually decide. The combination method will be applied according to the methodological resemblance in the selected articles using the Random Effect Model or the Fixed Effect Model. Also, for the included articles, forest plots will be drawn. For assessing statistical heterogeneity, the I² statistic and the Q-statistic test will be applied. In addition, funnel plots will be used for assessing non-significant study effects and potential reporting bias. Furthermore, Egger’s and Begg’s tests will be done, and publication bias will be indicated by significant findings (P < 0.05).

Conclusions

It is expected that the results of this study will be of benefit to researchers and clinicians for managing PDPH, and will be reported in conferences and publications.

Towards point-of-care diagnosis of Alzheimer's disease: Multi-analyte based portable chemiresistive platform for simultaneous detection of β-amyloid (1-40) and (1-42) in plasma

Label-free simultaneous detection of Alzheimer's disease (AD) specific biomarkers Aβ40 and Aβ42 peptides on a single platform using polypyrrole nanoparticle-based chemiresistive biosensors is reported here. The proposed interdigitated-microelectrode based inexpensive multisensor-platform can concurrently detect Aβ40 and Aβ42 in spiked-plasma in the range of 10-14 - 10-6 g/mL (with LoDs being 5.71 and 9.09 fg/mL, respectively), enabling the estimation of diagnostically significant Aβ42/Aβ40 ratio. A detailed study has been undertaken here to record the individual sensor responses against spiked-plasma samples with varying amounts and proportions of the two target peptides, towards enabling disease-progression monitoring using the Aβ-ratio. As compared to the existing cost-ineffective brain-imaging techniques such as PET and MRI, and the high-risk CSF based invasive AD biomarkers detecting procedures, the proposed approach offers a viable alternative for affordable point-of-care AD diagnostics, with possible usage in performance evaluation of therapeutic drugs. Towards point-of-care applications, the portable readout used in this work was conjugated with an android-based mobile app for data-acquisition and analysis.

Plasma Proteomic Biomarkers Relating to Alzheimer's Disease: A Meta-Analysis Based on Our Own Studies

Background and Objective: Plasma biomarkers for the diagnosis and stratification of Alzheimer's disease (AD) are intensively sought. However, no plasma markers are well established so far for AD diagnosis. Our group has identified and validated various blood-based proteomic biomarkers relating to AD pathology in multiple cohorts. The study aims to conduct a meta-analysis based on our own studies to systematically assess the diagnostic performance of our previously identified blood biomarkers. Methods: To do this, we included seven studies that our group has conducted during the last decade. These studies used either Luminex xMAP or ELISA to measure proteomic biomarkers. As proteins measured in these studies differed, we selected protein based on the criteria that it must be measured in at least four studies. We then examined biomarker performance using random-effect meta-analyses based on the mean difference between biomarker concentrations in AD and controls (CTL), AD and mild cognitive impairment (MCI), MCI, and CTL as well as MCI converted to dementia (MCIc) and non-converted (MCInc) individuals. Results: An overall of 2,879 subjects were retrieved for meta-analysis including 1,053 CTL, 895 MCI, 882 AD, and 49 frontotemporal dementia (FTD) patients. Six proteins were measured in at least four studies and were chosen for meta-analyses for AD diagnosis. Of them, three proteins had significant difference between AD and controls, among which alpha-2-macroglobulin (A2M) and ficolin-2 (FCN2) increased in AD while fibrinogen gamma chain (FGG) decreased in AD compared to CTL. Furthermore, FGG significantly increased in FTD compared to AD. None of the proteins passed the significance between AD and MCI, or MCI and CTL, or MCIc and MCInc, although complement component 4 (CC4) tended to increase in MCIc individuals compared to MCInc. Conclusions: The results suggest that A2M, FCN2, and FGG are promising biomarkers to discriminate AD patients from controls, which are worthy of further validation.

Biomarkers for the Clinical Diagnosis of Alzheimer's Disease: Metabolomics Analysis of Brain Tissue and Blood

With an increase in aging populations worldwide, age-related diseases such as Alzheimer's disease (AD) have become a global concern. At present, a cure for neurodegenerative disease is lacking. There is an urgent need for a biomarker that can facilitate the diagnosis, classification, prognosis, and treatment response of AD. The recent emergence of highly sensitive mass-spectrometry platforms and high-throughput technology can be employed to discover and catalog vast datasets of small metabolites, which respond to changed status in the body. Metabolomics analysis provides hope for a better understanding of AD as well as the subsequent identification and analysis of metabolites. Here, we review the state-of-the-art emerging candidate biomarkers for AD.

State-of-the-art of lumbar puncture and its place in the journey of patients with Alzheimer's disease

Recent advances in developing disease‐modifying therapies (DMT) for Alzheimer's disease (AD), and the recognition that AD pathophysiology emerges decades before clinical symptoms, necessitate a paradigm shift of health‐care systems toward biomarker‐guided early detection, diagnosis, and therapeutic decision‐making. Appropriate incorporation of cerebrospinal fluid biomarker analysis in clinical practice is an essential step toward system readiness for accommodating the demand of AD diagnosis and proper use of DMTs—once they become available. However, the use of lumbar puncture (LP) in individuals with suspected neurodegenerative diseases such as AD is inconsistent, and the perception of its utility and safety differs considerably among medical specialties as well as among regions and countries. This review describes the state‐of‐the‐art evidence concerning the safety profile of LP in older adults, discusses the risk factors for LP‐associated adverse events, and provides recommendations and an outlook for optimized use and global implementation of LP in individuals with suspected AD.

Preventing Post-Lumbar Puncture Headache

Post-lumbar puncture headache is the main adverse event from lumbar puncture and occurs in 3.5% to 33% of patients, causing functional and socio-professional disability. We searched the post-lumbar puncture headache literature and, based on this review and personal expertise, identified and addressed 19 frequently asked questions regarding post-lumbar puncture headache risk factors and prevention. Among the nonmodifiable factors, older age is associated with a lower incidence of post-lumbar puncture headache, while female sex, lower body mass index, and history of headache might be associated with increased risk. The use of atraumatic, noncutting needles is the most effective intervention for post-lumbar puncture headache prevention. These needles are not more difficult to use than cutting needles. Other commonly recommended measures (eg, fluid supplementation, caffeine) appear unhelpful, and some (eg, bed rest) may worsen post-lumbar puncture headache.

Assessment of main complications of regional anesthesia recorded in an acute pain unit in a tertiary care university hospital: a retrospective cohort

Background

Regional anesthesia has been increasingly used. Despite its low number of complications, they are associated with relevant morbidity. This study aims to evaluate the incidence of complications after neuraxial block and peripheral nerve block.

Methods

A retrospective cohort study was conducted, and data related to patients submitted to neuraxial block and peripheral nerve block at a tertiary university hospital from January 1, 2011 to December 31, 2017 were analyzed.

Results

From 10,838 patients referred to Acute Pain Unit, 1093(10.1%) had side effects or complications: 1039 (11.4%) submitted to neuraxial block and 54 (5.2%) to peripheral nerve block. The most common side effects after neuraxial block were sensory (48.5%) or motor deficits (11.8%), nausea or vomiting (17.5%) and pruritus (8.0%); The most common complications: 3 (0.03%) subcutaneous cell tissue hematoma, 3 (0.03%) epidural abscesses and 1 (0.01%) arachnoiditis. 204 of these patients presented sensory or motor deficits at hospital discharge and needed follow-up. Permanent peripheral nerve injury after neuraxial block had an incidence of 7.7:10,000 (0.08%). The most common side effects after peripheral nerve block were sensory deficits (52%) and 21 patients maintained follow-up due to symptoms persistence after hospital discharge.

Conclusion

Although we found similar incidences of side effects or even lower than those described, major complications after neuraxial block had a higher incidence, particularly epidural abscesses. Despite this, other serious complications, such as spinal hematoma and permanent peripheral nerve injury, are still rare.

Replication study of plasma proteins relating to Alzheimer's pathology

INTRODUCTION

This study sought to discover and replicate plasma proteomic biomarkers relating to Alzheimer's disease (AD) including both the "ATN" (amyloid/tau/neurodegeneration) diagnostic framework and clinical diagnosis.

METHODS

Plasma proteins from 972 subjects (372 controls, 409 mild cognitive impairment [MCI], and 191 AD) were measured using both SOMAscan and targeted assays, including 4001 and 25 proteins, respectively.

RESULTS

Protein co-expression network analysis of SOMAscan data revealed the relation between proteins and "N" varied across different neurodegeneration markers, indicating that the ATN variants are not interchangeable. Using hub proteins, age, and apolipoprotein E ε4 genotype discriminated AD from controls with an area under the curve (AUC) of 0.81 and MCI convertors from non-convertors with an AUC of 0.74. Targeted assays replicated the relation of four proteins with the ATN framework and clinical diagnosis.

DISCUSSION

Our study suggests that blood proteins can predict the presence of AD pathology as measured in the ATN framework as well as clinical diagnosis.

Differential effects on blood and cerebrospinal fluid immune protein markers and kynurenine pathway metabolites from aerobic physical exercise in healthy subjects

Mounting evidence shows that physical exercise modulates systemic inflammation. However, its effect on cerebrospinal fluid (CSF) immune-marker profiles in man are largely unknown. We here report a study on healthy subjects (n = 27, males = 12, mean age 28.7, range 22-52) allocated to either an acute exercise setting over four consecutive days, or a training intervention over 4 weeks. Paired plasma and CSF samples collected at baseline, after 7 days of exercise abstention, and the day after completion of the exercise interventions, were analyzed for protein inflammation markers using a multiplex proximity extension assay and neurotransmitters and kynurenine pathway (KP) metabolites using liquid chromatography, respectively. Routine cell counts, and albumin, immunoglobulin G and neurofilament light chain concentrations in CSF remained unchanged in both paradigms, while several inflammatory proteins became upregulated after acute exercise. However, only changes in three CSF (vascular endothelial growth factor-A, interleukin-7 and matrix metalloproteinase-10) and 12 plasma proteins reached significance levels after adjustment for multiple comparisons and exclusion of less stable proteins. Similarly, KP metabolites only changed among participants after acute exercise, while neurotransmitter levels, except for increased CSF serine, remained stable. Both in plasma and CSF changes in KP metabolites and inflammatory proteins correlated, suggesting that these processes are functionally linked. These findings suggest that acute aerobic physical exercise affects immune markers and KP metabolites systemically and in the CSF.

The Association of Blood-Based Inflammatory Factors IL-1β, TGF-β and CRP with Cognitive Function in Alzheimer's Disease and Mild Cognitive Impairment

OBJECTIVE

Many patients suffer from dementia in its most common form, Alzheimer's disease (AD). In this study, the levels of IL-1β, TGF-β and CRP, which are involved in the inflammatory response in Alzheimer's disease and its mild cognitive impairment (MCI), were measured and analyzed.

METHODS

Seventy nine subjects participated in this study (mean age: 75.56 years, female: 54.3%, AD: 26, MCI: 28, normal: 25). The overall cognitive function of the subjects and the severity of the disease stage were assessed using the Mini-Mental State Examination (MMSE-K), the Clinical Dementia Rating (CDR), the Global Deterioration Scale (GDS) and the Geriatric Depression Scale-Korean (GDS-K).

RESULTS

It was observed that patients with AD had significantly higher levels of IL-1β and TGF-β than the patients with MCI and normal controls. In addition, the MCI group showed a statistically significantly higher TGF-β concentration than the normal group.

CONCLUSION

These results suggest that IL-1β and TGF-β may be useful biological markers for patients with Alzheimer's disease.

Does post dural puncture headache exist in idiopathic intracranial hypertension? A pilot study

BACKGROUND/OBJECTIVE

Occurrence of post-dural puncture headache (PDPH) after diagnostic lumbar puncture (LP) for idiopathic intracranial hypertension (IIH) may seem very unlikely in clinical practice. Nevertheless, it has been suggested by several studies, mainly in sub-group analyses. We aimed to evaluate the prevalence of PDPH in an IIH population and determine any eventual predictive factors of PDPH occurrence.

METHODS

We conducted a retrospective multiple-center observational study. All newly diagnosed IIH patients who met the International Classification of Headache Disorders (ICHD-3) or the Dandy modified criteria were included from three different French hospitals. They all underwent LP following the same process with the same type of needle. We recorded PDPH occurring within five days after LP, as defined by ICHD-3 criteria.

RESULTS

Seventy-four IIH patients were recruited, of whom 23 (31%) presented with PDPH. Neither classical risk factors for PDPH such as body mass index, age or gender, nor cerebrospinal fluid opening pressure, or specific IIH features were associated with occurrence of PDPH.

CONCLUSION

PDPH can occur after LP in IIH patients. Clinicians should be aware of this possible event during the IIH diagnosis assessment and should not automatically reconsider IIH diagnosis. PDPH prevention using an atraumatic needle and dedicated PDPH treatment seem relevant in IIH patients.

Incidences and risk factors for post--dural puncture headache after neuraxial anaesthesia: A national inpatient database study in Japan

The reported incidence of post--dural puncture headache (PDPH) after neuraxial anaesthesia varies widely, depending on patient and procedural risk factors. Most previous studies have had small sample sizes and focused on obstetric patients. This study aimed to investigate the incidence of PDPH and factors associated with PDPH in non-obstetric and obstetric patients after neuraxial anaesthesia. We identified patients who underwent surgery with neuraxial anaesthesia between July 2010 and December 2017 from a Japanese nationwide inpatient administrative claims and discharge database. Factors associated with PDPH (body mass index (BMI), depression, spinal abnormalities, academic hospital and location of epidural anaesthesia) were examined using multivariable logistic analyses. The incidence of PDPH in non-obstetric patients after spinal anaesthesia, epidural anaesthesia and combined spinal epidural anaesthesia was 0.16%, 0.13% and 0.23% and in obstetric patients was 1.16%, 0.99% and 1.05%, respectively. Higher BMI was associated with decreased incidence of PDPH in non-obstetric patients receiving spinal anaesthesia and obstetric patients receiving epidural anaesthesia. In female patients receiving spinal anaesthesia, a history of depression was associated with increased incidence of PDPH. Being in an academic hospital was associated with decreased incidence of PDPH in male patients receiving spinal anaesthesia and female patients receiving spinal or epidural anaesthesia, but increased incidence of PDPH in male patients receiving epidural anaesthesia. Lumbar epidural anaesthesia was associated with increased incidence of PDPH in male patients, but decreased incidence of PDPH in obstetric patients compared with thoracic epidural anaesthesia. The present study identified several potential new risk factors for PDPH, and revealed that the incidence of PDPH in non-obstetric patients after neuraxial anaesthesia was lower than in obstetric patients.

Significance of Blood and Cerebrospinal Fluid Biomarkers for Alzheimer's Disease: Sensitivity, Specificity and Potential for Clinical Use

Alzheimer's disease (AD) is the most common type of dementia, affecting more than 5 million Americans, with steadily increasing mortality and incredible socio-economic burden. Not only have therapeutic efforts so far failed to reach significant efficacy, but the real pathogenesis of the disease is still obscure. The current theories are based on pathological findings of amyloid plaques and tau neurofibrillary tangles that accumulate in the brain parenchyma of affected patients. These findings have defined, together with the extensive neurodegeneration, the diagnostic criteria of the disease. The ability to detect changes in the levels of amyloid and tau in cerebrospinal fluid (CSF) first, and more recently in blood, has allowed us to use these biomarkers for the specific in-vivo diagnosis of AD in humans. Furthermore, other pathological elements of AD, such as the loss of neurons, inflammation and metabolic derangement, have translated to the definition of other CSF and blood biomarkers, which are not specific of the disease but, when combined with amyloid and tau, correlate with the progression from mild cognitive impairment to AD dementia, or identify patients who will develop AD pathology. In this review, we discuss the role of current and hypothetical biomarkers of Alzheimer's disease, their specificity, and the caveats of current high-sensitivity platforms for their peripheral detection.

Common neurodegenerative disorders in the perioperative setting: Recommendations for screening from the Society for Perioperative Assessment and Quality Improvement (SPAQI)

Aging is associated with normal and abnormal brain and cognitive changes. Due to the expected increase in older adults requiring surgery, perioperative clinicians will be increasingly encountering patients with neurodegenerative disease. To help perioperative clinicians understand signs of abnormal behaviors that may mark an undiagnosed neurodegenerative disorder and alert additional patient monitoring, The Society for Perioperative Assessment and Quality Improvement (SPAQI) worked with experts in dementia, neuropsychology, geriatric medicine, neurology, and anesthesiology to provide a summary of cognitive and behavioral considerations for patients with common neurodegenerative disorders being evaluated at preoperative centers. Patients with neurodegenerative disorders are at high risk for delirium due to known neurochemical disruptions, medication interactions, associated frailty, or vascular risk profiles presenting risk for repeat strokes. We provide basic information on the expected cognitive changes with aging, most common neurodegenerative disorders, a list of behavioral features and considerations to help differentiate neurodegenerative disorders. Finally, we propose screening recommendations intended for a multidisciplinary team in the perioperative setting.

Extreme Intracranial Hypotension With Brain Herniation Treated With Repeat Bolus Intrathecal Infusions

Intracranial hypotension (IH) is a relatively common condition associated with low cerebrospinal (CSF) pressure. The most typical symptom is orthostatic headache, although neurological deficits and changes in the level of consciousness, such as encephalopathy, stupor, and coma, may also occur. Uncomplicated CSF hypotension headaches generally resolve with rest, hydration, and analgesia. However, persistent cases may require an epidural blood patch (EBP) for resolution. Our report presents the case of a 50-year-old male with a history of intravenous (IV) drug abuse, positive for human immunodeficiency virus (HIV), hepatitis B virus (HBV), and hepatitis C virus (HCV) antibodies, who was admitted for new-onset headache and brain magnetic resonance imaging (MRI) findings suggesting CSF hypotension. The patient subsequently developed altered mental status with agonizing respirations, prompting intubation and admission to the intensive care unit (ICU) with neurosurgery consult. The initial exam revealed fixed and dilated pupils, suggestive of severe IH with brain herniation and the decision was made to proceed with an emergent intrathecal infusion with intraparenchymal intracranial pressure (ICP) monitoring, combined with EBP. A substantial clinical improvement was noted following the procedure. Within 45 minutes, the patient's mental status improved to normal and pupillary dilation and areflexia were no longer observed. While the procedure may need to be repeated in cases of late deterioration, this report provides evidence that intrathecal bolus saline infusion with simultaneous ICP monitoring may be considered an effective measure to treat extreme cases of IH with associated brain herniation. If performed in a timely fashion, improvement of ICP numbers, and clinical resolution can be quite rapid.

Elevation of plasma soluble amyloid precursor protein beta in Alzheimer's disease

INTRODUCTION

Beta-amyloid is considered to be a pathophysiological marker in Alzheimer's disease (AD). Soluble amyloid precursor proteins (sAPPs) -α (sAPPα) and -β (sAPPβ), which are the byproducts of non-amyloidogenic and amyloidogenic process of APP, respectively, have been repeatedly observed in the cerebrospinal fluids (CSF) of AD patients. The present study focused on the determination of sAPP levels in peripheral blood.

METHODS

The plasma protein levels of sAPPα and sAPPβ were measured with ELISA. Plasma from 52 AD patients, 98 amnestic mild cognitive impairment (MCI) patients, and 114 cognitively normal controls were compared.

RESULTS

The plasma level of sAPPβ was significantly increased in AD patients than in cognitively healthy controls. However, no significant change in plasma sAPPα was observed among the three groups. Furthermore, the plasma sAPPβ levels significantly correlated with cognitive assessment scales, such as clinical dementia rating (CDR), and mini-mental status examination (MMSE). Interestingly, sAPPα and sAPPβ had a positive correlation with each other in blood plasma, similar to previous studies on CSF sAPP. This correlation was stronger in the MCI and AD groups than in the cognitively healthy controls.

CONCLUSIONS

These results suggest that individuals with elevated plasma sAPPβ levels are at an increased risk of AD; elevation in these levels may reflect the progression of disease.

Reduction of AHI1 in the serum of Taiwanese with probable Alzheimer's disease

OBJECTIVE

The development of blood-based biomarkers for early diagnosis and treatment of Alzheimer's disease (AD) is desirable. In AD model mouse brain and neuronal cells, Abelson helper integration site-1 (AHI1) protein is reduced. AHI1 facilitates intracellular amyloid precursor protein (APP) translocation to inhibit amyloidogenic pathology of AD, and thus may be an AD biomarker.

METHODS

This study was conducted among 32 AD patients and 54 healthy control (HC) subjects. AHI1-related protein levels from initially collected serum samples in each group were screened using Western blotting. The protein concentrations of AHI1 and amyloid-β (Aβ), peptide(s) derived from APP, from all serum samples were analyzed using ELISA.

RESULTS

In AD serum, AHI1 and a large truncated C-terminal APP fragment were significantly reduced. The average concentrations of serum AHI1 and Aβ in AD were significantly lower than those in HC. Notably, AHI1 concentration in HC serum was decreased in an age-dependent manner, while it was consistently low in AD serum and had no correlation with Aβ or mini-mental state examination score. The receiver operating characteristic analysis on all subjects demonstrated an area under curve (AUC) value of 0.7 for AHI1 on AD diagnosis, while the AUC increased to 0.82 on the subjects younger than 77 years old, suggesting a good diagnostic performance of serum AHI1 for AD especially at relatively young age.

CONCLUSION

An early event of AHI1 reduction in the body of AD patients was observed. Serum AHI1 may be valuable for early diagnosis of AD.

Colorimetric Paper-Based Immunosensor for Simultaneous Determination of Fetuin B and Clusterin toward Early Alzheimer's Diagnosis

Alzheimer's disease is a devastating condition characterized by a progressive and slow brain decay in elders. Here, we developed a paper-based lateral flow immunoassay for simultaneous and fast determination of Alzheimer's blood biomarkers, fetuin B and clusterin. Selective antibodies to targeted biomarkers were immobilized on gold nanoparticles (AuNPs) and deposited on paper pads. After adding the sample on the paper-based device, the biofluid laterally flows toward the selective antibody, permitting AuNP-Ab accumulation on the test zone, which causes a color change from white to pink. Image analysis was performed using a customized algorithm for the automatic recognition of the area of analysis and color clustering. Colorimetric detection was compared to electrochemical methods for the precise quantification of biomarkers. The best performance was found for the color parameter "L*". Good linearity (R² = 0.988 and 0.998) and reproducibility (%RSD = 2.79% and 1.82%, N = 3) were demonstrated for the quantification of fetuin B and clusterin, respectively. Furthermore, the specificity of the immunosensor was tested on mixtures of proteins, showing negligible cross-reactivity and good performance in complex environments. We believe that our biosensor has a potential for early-stage diagnosis of Alzheimer's disease and toward a better understanding of Alzheimer's developing mechanisms.

Discovery and validation of plasma proteomic biomarkers relating to brain amyloid burden by SOMAscan assay

Introduction

Plasma proteins have been widely studied as candidate biomarkers to predict brain amyloid deposition to increase recruitment efficiency in secondary prevention clinical trials for Alzheimer's disease. Most such biomarker studies are targeted to specific proteins or are biased toward high abundant proteins.

Methods

4001 plasma proteins were measured in two groups of participants (discovery group = 516, replication group = 365) selected from the European Medical Information Framework for Alzheimer's disease Multimodal Biomarker Discovery study, all of whom had measures of amyloid.

Results

A panel of proteins (n = 44), along with age and apolipoprotein E (APOE) ε4, predicted brain amyloid deposition with good performance in both the discovery group (area under the curve = 0.78) and the replication group (area under the curve = 0.68). Furthermore, a causal relationship between amyloid and tau was confirmed by Mendelian randomization.

Discussion

The results suggest that high-dimensional plasma protein testing could be a useful and reproducible approach for measuring brain amyloid deposition.

Technological advances and changing indications for lumbar puncture in neurological disorders

Technological advances have changed the indications for and the way in which lumbar puncture is done. Suspected CNS infection remains the most common indication for lumbar puncture, but new molecular techniques have broadened CSF analysis indications, such as the determination of neuronal autoantibodies in autoimmune encephalitis. New screening techniques have increased sensitvity for pathogen detection and can be used to identify pathogens that were previously unknown to cause CNS infections. Evidence suggests that potential treatments for neurodegenerative diseases, such as Alzheimer's disease, will rely on early detection of the disease with the use of CSF biomarkers. In addition to being used as a diagnostic tool, lumbar puncture can also be used to administer intrathecal treatments as shown by studies of antisense oligonucleotides in patients with spinal muscular atrophy. Lumbar puncture is generally a safe procedure but complications can occur, ranging from minor (eg, back pain) to potentially devastating (eg, cerebral herniation). Evidence that an atraumatic needle tip design reduces complications of lumbar puncture is compelling, and reinforces the need to change clinical practice.

Identification of Blood Biomarkers for Alzheimer's Disease Through Computational Prediction and Experimental Validation

Background: Alzheimer's disease (AD) is the major cause of dementia in population aged over 65 years, accounting up to 70% dementia cases. However, validated peripheral biomarkers for AD diagnosis are not available up to present. In this study, we adopted a new strategy of combination of computational prediction and experimental validation to identify blood protein biomarkers for AD.

Methods: First, we collected tissue-based gene expression data of AD patients and healthy controls from GEO database. Second, we analyzed these data and identified differentially expressed genes for AD. Third, we applied a blood-secretory protein prediction program on these genes and predicted AD-related proteins in blood. Finally, we collected blood samples of AD patients and healthy controls to validate the potential AD biomarkers by using ELISA experiments and Western blot analyses.

Results: A total of 2754 genes were identified to express differentially in brain tissues of AD, among which 296 genes were predicted to encode AD-related blood-secretory proteins. After careful analysis and literature survey on these predicted blood-secretory proteins, ten proteins were considered as potential AD biomarkers, five of which were experimentally verified with significant change in blood samples of AD vs. controls by ELISA, including GSN, BDNF, TIMP1, VLDLR, and APLP2. ROC analyses showed that VLDLR and TIMP1 had excellent performance in distinguishing AD patients from controls (area under the curve, AUC = 0.932 and 0.903, respectively). Further validation of VLDLR and TIMP1 by Western blot analyses has confirmed the results obtained in ELISA experiments.

Conclusion: VLDLR and TIMP1 had better discriminative abilities between ADs and controls, and might serve as potential blood biomarkers for AD. To our knowledge, this is the first time to identify blood protein biomarkers for AD through combination of computational prediction and experimental validation. In addition, VLDLR was first reported here as potential blood protein biomarker for AD. Thus, our findings might provide important information for AD diagnosis and therapies.

Blood-based biomarkers for Alzheimer disease: mapping the road to the clinic

Biomarker discovery and development for clinical research, diagnostics and therapy monitoring in clinical trials have advanced rapidly in key areas of medicine - most notably, oncology and cardiovascular diseases - allowing rapid early detection and supporting the evolution of biomarker-guided, precision-medicine-based targeted therapies. In Alzheimer disease (AD), breakthroughs in biomarker identification and validation include cerebrospinal fluid and PET markers of amyloid-β and tau proteins, which are highly accurate in detecting the presence of AD-associated pathophysiological and neuropathological changes. However, the high cost, insufficient accessibility and/or invasiveness of these assays limit their use as viable first-line tools for detecting patterns of pathophysiology. Therefore, a multistage, tiered approach is needed, prioritizing development of an initial screen to exclude from these tests the high numbers of people with cognitive deficits who do not demonstrate evidence of underlying AD pathophysiology. This Review summarizes the efforts of an international working group that aimed to survey the current landscape of blood-based AD biomarkers and outlines operational steps for an effective academic-industry co-development pathway from identification and assay development to validation for clinical use.

Evolving Relevance of Neuroproteomics in Alzheimer's Disease

Substantial progress in the understanding of the biology of Alzheimer's disease (AD) has been achieved over the past decades. The early detection and diagnosis of AD and other age-related neurodegenerative diseases, however, remain a challenging scientific frontier. Therefore, the comprehensive discovery (relating to all individual, converging or diverging biochemical disease mechanisms), development, validation, and qualification of standardized biological markers with diagnostic and prognostic functions with a precise performance profile regarding specificity, sensitivity, and positive and negative predictive value are warranted.Methodological innovations in the area of exploratory high-throughput technologies, such as sequencing, microarrays, and mass spectrometry-based analyses of proteins/peptides, have led to the generation of large global molecular datasets from a multiplicity of biological systems, such as biological fluids, cells, tissues, and organs. Such methodological progress has shifted the attention to the execution of hypothesis-independent comprehensive exploratory analyses (opposed to the classical hypothesis-driven candidate approach), with the aim of fully understanding the biological systems in physiology and disease as a whole. The systems biology paradigm integrates experimental biology with accurate and rigorous computational modelling to describe and foresee the dynamic features of biological systems. The use of dynamically evolving technological platforms, including mass spectrometry, in the area of proteomics has enabled to rush the process of biomarker discovery and validation for refining significantly the diagnosis of AD. Currently, proteomics-which is part of the systems biology paradigm-is designated as one of the dominant matured sciences needed for the effective exploratory discovery of prospective biomarker candidates expected to play an effective role in aiding the early detection, diagnosis, prognosis, and therapy development in AD.

Increased Plasma Beta-Secretase 1 May Predict Conversion to Alzheimer's Disease Dementia in Individuals With Mild Cognitive Impairment

BACKGROUND

Increased beta-secretase 1 (BACE1) activity has consistently been detected in brain tissue and cerebrospinal fluid of subjects with mild cognitive impairment (MCI) and probable Alzheimer's disease (AD) compared with control subjects. The collection of cerebrospinal fluid by lumbar puncture is invasive. We sought to identify the presence of plasma BACE1 activity and determine potential alterations in subjects with MCI with clinical follow-up examinations for 3 years using patients with diagnosed probable AD dementia compared with healthy control subjects.

METHODS

Seventy-five patients with probable AD, 96 individuals with MCI, and 53 age-matched and sex-matched healthy control subjects were recruited from three independent international academic memory clinics and AD research expert centers. Plasma BACE1 activity was measured by a synthetic fluorescence substrate enzyme-linked immunosorbent assay. BACE1 protein expression was assessed by Western blotting using three different antibodies that recognize the epitopes of the N-terminus, C-terminus, and full-length BACE1.

RESULTS

Compared with healthy control subjects, plasma BACE1 activity (V_max) significantly increased by 53.2% in subjects with MCI and by 68.9% in patients with probable AD. Subjects with MCI who converted to probable AD dementia at follow-up examinations exhibited significantly higher BACE1 activity compared with cognitively stable MCI nonconverters and showed higher levels of BACE1 activity than patients with AD.

CONCLUSIONS

Plasma BACE1 activity is significantly increased in MCI converters and patients with probable AD. The sensitivities and specificities of BACE1 activity for the patients were 84% and 88%, respectively. Our results indicate that plasma BACE1 activity may be a biomarker for AD risk and could predict progression from prodromal to probable AD dementia.

Safety of lumbar puncture procedure in an international research setting during acute HIV infection

Background: Cerebrospinal fluid (CSF) sampling at the time of acute HIV infection (AHI) is crucial in understanding NeuroAIDS pathogenesis. Here, we report on the safety of performing a lumbar puncture (LP) during untreated AHI and follow-up after initiation of combination antiretroviral therapy (cART). Methods: We reviewed clinical records of participants who took part in an AHI protocol in Bangkok, Thailand, including untreated AHI subjects (baseline), and longitudinal visits following immediate initiation of cART to assess rates and risk of post-lumbar puncture headaches (PLPH). A cerebrospinal fluid (CSF) volume of 10-20 mL was collected using standard cutting-edge or atraumatic needles. Results: From April 2009 to February 2016, 195 LPs were performed, of which 89 (46%) were at baseline. The LP procedures at baseline were not associated with an additional PLPH risk as compared to repeat LPs after cART initiation (26/89 [29%] vs 4/27 [15%], respectively; P=0.134). Higher body mass index (BMI) at baseline (P=0.070) and use of an atraumatic needle (P=0.058) had trend-level associations with reduced PLPH. A higher CSF volume collection (20 mL) was independently associated with a lower PLPH frequency (P=0.024). This association was similar in a subgroup analysis with the use of atraumatic needles. The CD4+ T lymphocyte count, blood and CSF HIV viral load, Fiebig staging, and the presence of an acute retroviral syndrome did not correlate with risk for PLPH (all P>0.05). Conclusion: The frequency of PLPH during AHI was similar to that seen in the setting of cART-treated HIV infection and not higher with a larger CSF volume collection. Our study adds to the existing evidence that atraumatic needles should be used to minimise the risk of PLPH.

A Decade of Blood Biomarkers for Alzheimer's Disease Research: An Evolving Field, Improving Study Designs, and the Challenge of Replication

Blood-based biomarkers represent a less invasive and potentially cheaper approach for aiding Alzheimer's disease (AD) detection compared with cerebrospinal fluid and some neuroimaging biomarkers. Acknowledging that many in the field have made great progress, here we review some of the work that our group has pursued to identify and validate blood-based proteomic biomarkers through both case control and AD pathology endophenotype-based approaches. Our focus is primarily to identify a minimally invasive and hopefully cost-effective blood-based biomarker to reduce screen failure in clinical trials where participants have prodromal or even pre-clinical disease. We summarize some of the key findings and approaches taken in these biomarker studies, while addressing the main challenges, including that of limited replication in the field, and discuss opportunities for biomarker development.

Predictors and incidence of orthostatic headache associated with lumbar drain placement following endoscopic endonasal skull base surgery

BACKGROUND

Orthostatic headache (OH) is a potential complication of lumbar drainage (LD) usage. The incidence and risk factors for OH with the use of lumbar drainage during endoscopic endonasal procedures have not been documented.

OBJECTIVE

To investigate the incidence of post-procedure OHs associated with placement of LD in patients undergoing endoscopic endonasal procedures.

METHODS

We prospectively noted the placement of LDs in a consecutive series of endoscopic endonasal skull base surgeries. Charts were retrospectively reviewed, and patients were divided into two groups: those with OH and those without. The patient demographics, drain durations, imaging findings of intracranial hypotension, pathologies and need for a blood patch were compared between the two groups.

RESULTS

Two hundred forty-nine patients were included in the study. Seven patients (2.8%) suffered post-dural puncture OH, which was mild to moderate and disappeared 2-8 days (median 3 days) after treatment. Blood patches were used in four patients. Significant predisposing factors were age (33.0 vs. 53.5, P = 0.014) and a strong trend for female gender (85.7% vs. 47.9%, P = 0.062). BMI and drain duration were not significant. Postoperative intracranial hypotension was diagnosed radiographically in 43% of OH patients and in 5.4% of those without OH (P = 0.003). Four (1.6%) patients required treatment with an epidural blood patch.

CONCLUSION

OH associated with intracranial hypotension in patients undergoing endoscopic endonasal procedures with LDs is an infrequent complication seen more commonly in young female patients. Radiographic signs of intracranial hypotension are a specific but not sensitive test for OH.

Effect of Head and Neck Immobilization on Postspinal Headache: A Randomized Controlled Trial

PURPOSE

The purpose of the study was to determine the effect of head and neck immobilization on postdural puncture headache (PDPH) through the use of cervical collars.

DESIGN

This was a fully randomized controlled trial.

METHOD

The sample group of the study consisted of 120 patients. Patients in the experimental group were followed up by using the appropriate cervical collar after the operation. The cervical collar was kept on until mobilization. Follow-ups of patients in the control group continued without limiting head and neck movements. Headaches of patients in the experimental and control groups at 24, 48, and 72 hours after the operation were determined.

FINDINGS

The average age of the patients in the experimental group was 22.70 ± 2.72, whereas it was 22.93 ± 3.29 in the control group. The mean body mass index of the experimental group and control group was 24.24 ± 2.62 and 23.46 ± 3.03, respectively. The mean scores of the patients in the experimental and control groups on the Numeric Rating Scale were statistically significant in favor of patients in the experimental group in the interval of 24 and 48 hours (P < .05) and was not statistically significant after 72 hours (P > .05).

CONCLUSION

This study showed that prolonged immobility of the neck, in addition to bed rest, could not prevent PDPHs. The use of a cervical collar may help to delay PDPHs. may help to delay PDPHs.

Role of lumbar drains in contemporary endonasal skull base surgery: Meta-analysis and systematic review

BACKGROUND

Historically, lumbar drains (LD) have played a prominent role in endonasal skull base surgery. Over the past few decades, advancements in techniques have augmented our ability to successfully reconstruct complex skull base defects and often obviates the need for cerebrospinal fluid (CSF) diversion. Clarity on the appropriate use of LDs is needed.

OBJECTIVE

To examine the literature for the need for LDs in contemporary skull base reconstruction after resection of skull base tumors.

METHODS

A systematic literature review of English language articles by using PubMed and Ovid. Search terms included "lumbar drain," "CSF leak," and "endoscopic endonasal reconstruction." Articles were included when they pertained to adults, used current methods for reconstruction (i.e., multilayered repair or vascularized tissue), and addressed CSF leak rates secondary to endoscopic resection of skull base masses. All the studies discussed CSF leaks that resulted from traumatic-, idiopathic-, or sinus surgery-related iatrogenic causes were excluded. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were followed.

RESULTS

A total of five articles met inclusion criteria. These comprised 376 endoscopic skull base tumor resection and reconstruction cases; 5.59% developed postoperative CSF leaks. A meta-analysis was conducted by incorporating three studies that met criteria based on testing for heterogeneity. The average odds ratio for postoperative CSF leak for patients who did not have an LD relative to patients who had an LD was 0.590 (95% confidence interval, 0.214-1.630). Given a p value of 0.30, the results demonstrated a lack of statistically significant improvement between patients who had an LD and patients who did not have an LD. Various details, such as the defect size and type of CSF leak, were not consistently reported among studies.

CONCLUSIONS

Available evidence for the use of LDs in skull base surgery is of poor quality. Analysis of the literature revealed heterogenous and varied reporting in the primary literature. Further studies that include randomized controlled trials are needed.

Metabolomic-guided discovery of Alzheimer's disease biomarkers from body fluid

The rapid increase in the older population has made age-related diseases like Alzheimer's disease (AD) a global concern. Given that there is still no cure for this neurodegenerative disease, the drastic growth in the number of susceptible individuals represents a major emerging threat to public health. The poor understanding of the mechanisms underlying AD is deemed the greatest stumbling block against progress in definitive diagnosis and management of this disease. There is a dire need for biomarkers that can facilitate early diagnosis, classification, prognosis, and treatment response. Efforts have been directed toward discovery of reliable and distinctive AD biomarkers but with very little success. With the recent emergence of high-throughput technology that is able to collect and catalogue vast datasets of small metabolites, metabolomics offers hope for a better understanding of AD and subsequent identification of biomarkers. This review article highlights the potential of using multiple metabolomics platforms as useful means in uncovering AD biomarkers from body fluids. © 2017 Wiley Periodicals, Inc.

Biomarkers in Sporadic and Familial Alzheimer's Disease

Most forms of Alzheimer's disease (AD) are sporadic (sAD) or inherited in a non-Mendelian fashion, and less than 1% of cases are autosomal-dominant. Forms of sAD do not exhibit familial aggregation and are characterized by complex genetic and environmental interactions. Recently, the expansion of genomic methodologies, in association with substantially larger combined cohorts, has resulted in various genome-wide association studies that have identified several novel genetic associations of AD. Currently, the most effective methods for establishing the diagnosis of AD are defined by multi-modal pathways, starting with clinical and neuropsychological assessment, cerebrospinal fluid (CSF) analysis, and brain-imaging procedures, all of which have significant cost- and access-to-care barriers. Consequently, research efforts have focused on the development and validation of non-invasive and generalizable blood-based biomarkers. Among the modalities conceptualized by the systems biology paradigm and utilized in the "exploratory biomarker discovery arena", proteome analysis has received the most attention. However, metabolomics, lipidomics, transcriptomics, and epigenomics have recently become key modalities in the search for AD biomarkers. Interestingly, biomarker changes for familial AD (fAD), in many but not all cases, seem similar to those for sAD. The integration of neurogenetics with systems biology/physiology-based strategies and high-throughput technologies for molecular profiling is expected to help identify the causes, mechanisms, and biomarkers associated with the various forms of AD. Moreover, in order to hypothesize the dynamic trajectories of biomarkers through disease stages and elucidate the mechanisms of biomarker alterations, updated and more sophisticated theoretical models have been proposed for both sAD and fAD.

Fluid Biomarkers in Clinical Trials of Alzheimer's Disease Therapeutics

With the demographic shift of the global population toward longer life expectancy, the number of people living with Alzheimer’s disease (AD) has rapidly expanded and is projected to triple by the year 2050. Current treatments provide symptomatic relief but do not affect the underlying pathology of the disease. Therapies that prevent or slow the progression of the disease are urgently needed to avoid this growing public health emergency. Insights gained from decades of research have begun to unlock the pathophysiology of this complex disease and have provided targets for disease-modifying therapies. In the last decade, few therapeutic agents designed to modify the underlying disease process have progressed to clinical trials and none have been brought to market. With the focus on disease modification, biomarkers promise to play an increasingly important role in clinical trials. Six biomarkers have now been included in diagnostic criteria for AD and are regularly incorporated into clinical trials. Three biomarkers are neuroimaging measures – hippocampal atrophy measured by magnetic resonance imaging (MRI), amyloid uptake as measured by Pittsburg compound B positron emission tomography (PiB-PET), and decreased fluorodeoxyglucose (18F) uptake as measured by PET (FDG-PET) – and three are sampled from fluid sources – cerebrospinal fluid levels of amyloid β42 (Aβ42), total tau, and phosphorylated tau. Fluid biomarkers are important because they can provide information regarding the underlying biochemical processes that are occurring in the brain. The purpose of this paper is to review the literature regarding the existing and emerging fluid biomarkers and to examine how fluid biomarkers have been incorporated into clinical trials.

[Cerebrospinal fluid leakage. Indications, technique and results of treatment with a blood patch]

BACKGROUND

In most cases cerebrospinal fluid (CSF) leaks are iatrogenic and caused by medical interventions, such as lumbar puncture, peridural anesthesia and surgical interventions on the spine, However, spontaneous cerebral hypotension is currently detected more frequently due to improvements in diagnostic possibilities but often the cause cannot be clarified with certainty.

METHODS

There are various diagnostic tools for confirming the diagnosis and searching for the site of CSF leakage, such as postmyelography computed tomography (postmyelo-CT), indium(111) radioisotope cisternography and (myelo) magnetic resonance imaging (MRI), which show different sensitivities. In accordance with own experience native MRI with fat-saturated T2-weighted sequences is often sufficient for diagnosing CSF leakage and the site. For the remaining cases an additional postmyelo-CT or alternatively myelo-MRI is recommended. In some patients with spontaneous cranial hypotension multiple CSF leaks are found at different spinal levels. The main symptom in most cases is an orthostatic headache. While post-puncture syndrome is self-limiting in many cases, spontaneous CSF leakage usually requires blood patch therapy. A lumbar blood patch can be safely carried out under guidance by fluoroscopy. In the case of a cervical or dorsal blood patch, CT guidance is recommended, which ensures epidural application of the blood patch and minimizes the risk of damaging the spinal cord. Despite a high success rate at the first attempt with a blood patch of up to 85%, some cases require repeating the blood patch. A targeted blood patch of a CSF leak should generally be favoured over a blindly placed blood patch; nevertheless, if a CSF leak cannot be localized by CT or MRI a therapeutic attempt with a lumbar blood patch can be carried out. After a successful blood patch intracranial hygromas and pachymeningeal enhancement in the head show fast regression; however, epidural hygromas of the spine can persist for a period of several months, even though patients are already free of symptoms.

CONCLUSION

In total, blood patch therapy is a safe and technically relative simple method with a high success rate. Therefore, it represents the therapy of choice in patients with spontaneous cerebrospinal fluid leakage as well as in cases of post-lumbar puncture syndrome refractory to conservative therapy.