Cerebrospinal fluid and lumbar puncture: a practical review

Subdural haematoma mimics

A subdural haematoma (SDH) is a frequently encountered pathology seen on an emergency room computed tomography (CT) head scan. An extra-axial crescentic density along the convexity of the brain or within the interhemispheric fissure is generally thought to represent a SDH; however, SDH mimics are known to occur in nature, and can be broadly classified under the subcategories of normal anatomy, artefacts, tumour, inflammation, infection, ischaemia, trauma, and iatrogenic. Understanding the typical characteristics of a SDH, knowledge of normal anatomy, close inspection of the morphology of the subdural process, changes to the adjacent structures, and rigorous attention to clinical details may reveal subtle clues that distinguish a true SDH from a mimic. This is crucial in appropriately directing clinical management. This review amalgamates most of the rare subdural processes that have been reported to mimic SDH, and discusses the imaging and clinical features that help to differentiate between them. This topic is highly valuable for radiology trainees, general radiologists, and emergency room physicians, and may serve as a refresher for the practising neuroradiologist.

A Guide to Bacterial Culture Identification And Results Interpretation

PURPOSE

To provide a guide to interpreting bacterial culture results.

METHODS

Studies were identified via a PubMed literature search (from 1966 to January 2018). Search terms included microbial sensitivity tests, microbial drug resistance, and anti-infective agents/pharmacology. Articles were included if they were published in English. References within identified articles were also reviewed.

RESULTS

This paper reviewed core concepts of interpreting bacterial culture results, including timing of cultures, common culture sites, potential for contamination, interpreting the Gram stain, role of rapid diagnostic tests, conventional antibiotic susceptibility testing, and automated testing.

CONCLUSION

This guide can assist pharmacists in their role as integral members of the antimicrobial stewardship team in an effort to improve patient care.

Metabolome-based signature of disease pathology in MS

BACKGROUND

Diagnostic delays are common for multiple sclerosis (MS) since diagnosis typically depends on the presentation of nonspecific clinical symptoms together with radiologically-determined central nervous system (CNS) lesions. It is important to reduce diagnostic delays as earlier initiation of disease modifying therapies mitigates long-term disability. Developing a metabolomic blood-based MS biomarker is attractive, but prior efforts have largely focused on specific subsets of metabolite classes or analytical platforms. Thus, there are opportunities to interrogate metabolite profiles using more expansive and comprehensive approaches for developing MS biomarkers and for advancing our understanding of MS pathogenesis.

METHODS

To identify putative blood-based MS biomarkers, we comprehensively interrogated the metabolite profiles in 12 non-Hispanic white, non-smoking, male MS cases who were drug naïve for 3 months prior to biospecimen collection and 13 non-Hispanic white, non-smoking male controls who were frequency matched to cases by age and body mass index. We performed untargeted two-dimensional gas chromatography and time-of-flight mass spectrometry (GCxGC-TOFMS) and targeted lipidomic and amino acid analysis on serum. 325 metabolites met quality control and supervised machine learning was used to identify metabolites most informative for MS status. The discrimination potential of these select metabolites were assessed using receiver operator characteristic curves based on logistic models; top candidate metabolites were defined as having area under the curves (AUC) >80%. The associations between whole-genome expression data and the top candidate metabolites were examined, followed by pathway enrichment analyses. Similar associations were examined for 175 putative MS risk variants and the top candidate metabolites.

RESULTS

12 metabolites were determined to be informative for MS status, of which 6 had AUCs >80%: pyroglutamate, laurate, acylcarnitine C14:1, N-methylmaleimide, and 2 phosphatidylcholines (PC ae 40:5, PC ae 42:5). These metabolites participate in glutathione metabolism, fatty acid metabolism/oxidation, cellular membrane composition, and transient receptor potential channel signaling. Pathway analyses based on the gene expression association for each metabolite suggested enrichment for pathways associated with apoptosis and mitochondrial dysfunction. Interestingly, the predominant MS genetic risk allele HLA-DRB1×15:01 was associated with one of the 6 top metabolites.

CONCLUSION

Our analysis represents the most comprehensive description of metabolic changes associated with MS in serum, to date, with the inclusion of genomic and genetic information. We identified atypical metabolic processes that differed between MS patients and controls, which may enable the development of biological targets for diagnosis and treatment.

Proteomic Analysis of Cerebrospinal Fluid: A Search for Biomarkers of Neuropsychiatric Systemic Lupus Erythematosus

Background:

Neuropsychiatric systemic lupus erythematosus or NPSLE, as its name suggests, refers to the neurological and psychiatric manifestations of Systemic Lupus Erythematosus (SLE). In clinical practice, it is often difficult to reach an accurate diagnosis, as this disease presents differently in different patients, and the available diagnostic tests are often not specific enough.

Objectives:

The aim of this study was to search for proteomic biomarkers in cerebrospinal fluid that could be proposed as diagnostic aids for this disease.

Methods:

The proteomic profile of cerebrospinal fluid samples of 19 patients with NPSLE, 12 patients with SLE and no neuropsychiatric manifestation (SLEnoNP), 6 patients with neuropsychiatric symptoms but no SLE (NPnoSLE), 5 with Other Autoimmune Disorders without neuropsychiatric manifestations (OADs), and 4 Healthy Controls (HC), were obtained by two-dimensional gel electrophoresis and compared using ImageMaster Platinum 7.0 software.

Results:

The comparative analysis of the different study groups revealed three proteins of interest that were consistently over-expressed in NPSLE patients. These were identified by mass spectrometry as albumin (spot 16), haptoglobin (spot 160), and beta-2 microglobulin (spot 161).

Conclusion:

This work is one of the few proteomic studies of NPSLE that uses cerebrospinal fluid as the biological sample. Albumin has previously been proposed as a potential biomarker of rheumatoid arthritis and SLE, which is coherent with these results; but this is the first report of haptoglobin and beta-2 microglobulin in NPSLE, although haptoglobin has been associated with increased antibody production and beta-2 microglobulin with lupus nephritis.

Meningeal inflammatory response and fibrous tissue remodeling around intracortical implants: An in vivo two-photon imaging study

Meningeal inflammation and encapsulation of neural electrode arrays is a leading cause of device failure, yet little is known about how it develops over time or what triggers it. This work characterizes the dynamic changes of meningeal inflammatory cells and collagen-I in order to understand the meningeal tissue response to neural electrode implantation. We use in vivo two-photon microscopy of CX3CR1-GFP mice over the first month after electrode implantation to quantify changes in inflammatory cell behavior as well as meningeal collagen-I remodeling. We define a migratory window during the first day after electrode implantation hallmarked by robust inflammatory cell migration along electrodes in the meninges as well as cell trafficking through meningeal venules. This migratory window attenuates by 2 days post-implant, but over the next month, the meningeal collagen-I remodels to conform to the surface of the electrode and thickens. This work shows that there are distinct time courses for initial meningeal inflammatory cell infiltration and meningeal collagen-I remodeling. This may indicate a therapeutic window early after implantation for modulation and mitigation of meningeal inflammation.

Choroid plexus genes for CSF production and brain homeostasis are altered in Alzheimer's disease

Background

The roles of the choroid plexus (CP) and cerebrospinal fluid (CSF) production have drawn increasing attention in Alzheimer’s disease (AD) research. Specifically, studies document markedly decreased CSF production and turnover in moderate-to-severe AD. Moreover, reduced CP function and CSF turnover lead to impaired clearance of toxic metabolites, likely promote neuroinflammation, and may facilitate neuronal death during AD progression. We analyzed CP gene expression in AD compared with control subjects, specifically considering those genes involved with CSF production and CP structural integrity.

Methods

The Brown-Merck Gene Expression Omnibus (GEO) database (CP transcripts) was mined to examine changes in gene expression in AD compared to controls with a focus on assorted genes thought to play a role in CSF production. Specifically, genes coding for ion transporters in CP epithelium (CPE) and associated enzymes like Na–K-ATPase and carbonic anhydrase, aquaporins, mitochondrial transporters/enzymes, blood–cerebrospinal fluid barrier (BCSFB) stability proteins, and pro-inflammatory mediators were selected for investigation. Data were analyzed using t test p-value and fold-change analysis conducted by the GEO2R feature of the GEO database.

Results

Significant expression changes for several genes were observed in AD CP. These included disruptions to ion transporters (e.g., the solute carrier gene SLC4A5, p = 0.004) and associated enzyme expressions (e.g., carbonic anhydrase CA4, p = 0.0001), along with decreased expression of genes involved in BCSFB integrity (e.g., claudin CLDN5, p = 0.039) and mitochondrial ATP synthesis (e.g., adenosine triphosphate ATP5L, p = 0.0004). Together all changes point to disrupted solute transport at the blood–CSF interface in AD. Increased expression of pro-inflammatory (e.g., interleukin IL1RL1, p = 0.00001) and potential neurodegenerative genes (e.g., amyloid precursor APBA3, p = 0.002) also implicate disturbed CP function.

Conclusions

Because the altered expression of numerous transcripts in AD-CP help explain decreased CSF production in AD, these findings represent a first step towards identifying novel therapeutic targets in AD.

Electronic supplementary material

The online version of this article (10.1186/s12987-018-0120-7) contains supplementary material, which is available to authorized users.

Ultrasound-Assisted Lumbar Puncture in a Neuromuscular Clinic has a High Success Rate and Less Pain

BACKGROUND

Lumbar puncture (LP) performed with the assistance of ultrasound (US) may improve success rate, with fewer puncture attempts and less pain.

OBJECTIVES

To explore the utility of US-assisted LP in a neuromuscular clinic.

METHODS

We performed a prospective, randomized, open-label study between May 2016 and January 2017. The primary outcome measure was LP success rate, and the secondary outcome measures included procedure time, number of attempts, and the levels of pain, anxiety, and satisfaction.

RESULTS

Lumbar puncture was performed in 40 consecutive patients. Ultrasound-assisted LP had a 100% success rate, compared with 85% (95% confidence interval: 58%-96%) without US assistance, although this difference failed to reach statistical significance. Ultrasound-assisted LP was associated with less pain and, also in patients >60 years of age, with fewer needle insertions. Both groups reported high satisfaction rates, regardless of the use of US.

CONCLUSION

Ultrasound-assisted LP has a high success rate and less pain than unassisted LP, and can be accomplished easily in the outpatient neuromuscular clinic setting equipped with US.

Use of Blood Biomarkers in the Assessment of Sports-Related Concussion-A Systematic Review in the Context of Their Biological Significance

OBJECTIVES

To critically review current knowledge on the positive and negative predictive value of blood biomarkers for concussion; to illustrate the clinical and biological contexts that help evaluate the use of these markers in sport-related traumatic brain injuries (TBIs).

METHODS

This systematic review was performed in accordance with PRISMA guidelines. We reviewed the measurement, clinical utility, endpoint, and biological significance of blood biomarkers in concussion.

RESULTS

A total of 4352 publications were identified. Twenty-six articles relating to blood biomarkers were included in the review. Four common blood biomarkers, namely S100B, tau, neuron-specific enolase (NSE), and glial fibrillary acidic protein (GFAP), were examined. Overall, the studies showed S100B measurement and use, either acutely or at several time points, can distinguish injured from noninjured patients with an uncertain degree of utility in predicting mortality. At present, S100B has largely become an acceptable biomarker of TBI; however, studies have begun to highlight the need to incorporate clinical symptoms instead of S100B concentration in isolation on the basis of inconsistent results and lack of specificity across published studies. Further research is needed to evaluate and validate the use of tau, NSE, and GFAP as a diagnostic aid in the management of concussion and TBI.

CONCLUSIONS

At present, blood biomarkers have only a limited role in the evaluation and management of concussion. Although several biomarkers of brain injury have been identified, continued research is required. S100B holds promise as the most clinically useful diagnostic biomarker. Blood biomarkers, in combination with other clinical data, such as head computed tomography, would maximize the diagnostic accuracy. The methodological limitations evident in blood biomarker research results in the need for the clinical utility of blood biomarker use in concussion to be further explored.

Accurate, strong, and stable reporting of choroid plexus epithelial cells in transgenic mice using a human transthyretin BAC

BACKGROUND

Choroid plexus epithelial cells express high levels of transthyretin, produce cerebrospinal fluid and many of its proteins, and make up the blood-cerebrospinal fluid barrier. Choroid plexus epithelial cells are vital to brain health and may be involved in neurological diseases. Transgenic mice containing fluorescent and luminescent reporters of these cells would facilitate their study in health and disease, but prior transgenic reporters lost expression over the early postnatal period.

METHODS

Human bacterial artificial chromosomes in which the transthyretin coding sequence was replaced with DNA for tdTomato or luciferase 2 were used in pronuclear injections to produce transgenic mice. These mice were characterized by visualizing red fluorescence, immunostaining, real-time reverse transcription polymerase chain reaction, and luciferase enzyme assay.

RESULTS

Reporters were faithfully expressed in cells that express transthyretin constitutively, including choroid plexus epithelial cells, retinal pigment epithelium, pancreatic islets, and liver. Expression of tdTomato in choroid plexus began at the appropriate embryonic age, being detectable by E11.5. Relative levels of tdTomato transcript in the liver and choroid plexus paralleled relative levels of transcripts for transthyretin. Expression remained robust over the first postnatal year, although choroid plexus transcripts of tdTomato declined slightly with age whereas transthyretin remained constant. TdTomato expression patterns were consistent across three founder lines, displayed no sex differences, and were stable across several generations. Two of the tdTomato lines were bred to homozygosity, and homozygous mice are healthy and fertile. The usefulness of tdTomato reporters in visualizing and analyzing live Transwell cultures was demonstrated. Luciferase activity was very high in homogenates of choroid plexus and continued to be expressed through adulthood. Luciferase also was detectable in eye and pancreas.

CONCLUSIONS

Transgenic mice bearing fluorescent and luminescent reporters of transthyretin should prove useful for tracking transplanted choroid plexus epithelial cells, for purifying the cells, and for reporting their derivation from stem cells. They also should prove useful for studying transthyretin synthesis by other cell types, as transthyretin has been implicated in many functions and conditions, including clearance of β-amyloid peptides associated with Alzheimer's disease, heat shock in neurons, processing of neuropeptides, nerve regeneration, astrocyte metabolism, and transthyretin amyloidosis.

Therapeutic lumbar puncture for headache in idiopathic intracranial hypertension: Minimal gain, is it worth the pain?

Background

Headache is disabling and prevalent in idiopathic intracranial hypertension. Therapeutic lumbar punctures may be considered to manage headache. This study evaluated the acute effect of lumbar punctures on headache severity. Additionally, the effect of lumbar puncture pressure on post-lumbar puncture headache was evaluated.

Methods

Active idiopathic intracranial hypertension patients were prospectively recruited to a cohort study, lumbar puncture pressure and papilloedema grade were noted. Headache severity was recorded using a numeric rating scale (NRS) 0–10, pre-lumbar puncture and following lumbar puncture at 1, 4 and 6 hours and daily for 7 days.

Results

Fifty two patients were recruited (mean lumbar puncture opening pressure 32 (28–37 cmCSF). At any point in the week post-lumbar puncture, headache severity improved in 71% (but a small reduction of −1.1 ± 2.6 numeric rating scale) and exacerbated in 64%, with 30% experiencing a severe exacerbation ≥ 4 numeric rating scale. Therapeutic lumbar punctures are typically considered in idiopathic intracranial hypertension patients with severe headaches (numeric rating scale ≥ 7). In this cohort, the likelihood of improvement was 92% (a modest reduction of headache pain by −3.0 ± 2.8 numeric rating scale, p = 0.012, day 7), while 33% deteriorated. Idiopathic intracranial hypertension patients with mild (numeric rating scale 1–3) or no headache (on the day of lumbar puncture, prior to lumbar puncture) had a high risk of post- lumbar puncture headache exacerbation (81% and 67% respectively). Importantly, there was no relationship between lumbar puncture opening pressure and headache response after lumbar puncture.

Conclusion

Following lumbar puncture, the majority of idiopathic intracranial hypertension patients experience some improvement, but the benefit is small and post-lumbar puncture headache exacerbation is common, and in some prolonged and severe. Lumbar puncture pressure does not influence the post-lumbar puncture headache.

Characterising the patient experience of diagnostic lumbar puncture in idiopathic intracranial hypertension: a cross-sectional online survey

OBJECTIVES

Patients with idiopathic intracranial hypertension (IIH) usually require multiple lumbar punctures (LPs) during the course of their disease, and often report significant morbidity associated with the procedure. The aim of this study was to assess the patient's experience of diagnostic LP in IIH.

DESIGN, METHODS AND PARTICIPANTS

A cross-sectional study of patients with IIH was conducted using an anonymous online survey, with the questions designed in collaboration with IIH UK (the UK IIH charity). Responses were collated over a 2-month period from April to May 2015. Patients were asked to quantify responses using a Verbal Rating Score (VRS) 0-10 with 0 being the minimum and 10 the maximum score.

RESULTS

502 patients responded to the survey, of which 463 were analysed for this study. 40% of patients described severe pain during the LP (VRS ≥8), and the median pain score during the LP was 7 (VRS, IQR 5-7). The majority of patients felt they received insufficient pain relief (85%). Levels of anxiety about future LPs were high (median VRS 7, IQR 4-10), with 47% being extremely anxious (VRS ≥8). LPs performed as an emergency were associated with significantly greater pain scores compared with elective procedures (median 7, IQR 5-7 vs 6, IQR 4-8, p=0.012). 10.7% went on to have an X-ray-guided procedure due to failure of the initial LP, and the body mass index was significantly higher in this group (mean kg/m²40.3 vs 35.5, p=0.001). Higher LP pain scores (VRS) were significantly associated with poorly informed patients (Spearman's correlation, r=-0.32, p<0.001). Patients felt more informed when the LP was performed by a specialist registrar compared with a junior doctor (median 7 vs 5, p=0.001) or a consultant compared with a junior doctor (median 8 vs 5, p<0.001).

CONCLUSIONS

This study was commissioned by the IIH patient group and is the first to document the patient experience of diagnostic LPs in IIH. It shows that the majority of these patients are experiencing significant morbidity from pain and anxiety. Patient experience of LP may be improved through changing clinical practice to include universal detailed preprocedural information, and where possible, avoiding emergency LPs in favour of LPs booked on an elective day-case unit.

Investigation of the optimal duration of bed rest in the supine position to reduce complications after lumbar puncture combined with intrathecal chemotherapy: a multicenter prospective randomized controlled trial

Purpose

This randomized, open-label trial was conducted to investigate the optimal duration of bed rest after intrathecal chemotherapy to reduce the incidence of complications without increasing patients’ tolerance to long-term bed rest.

Methods

A total of 390 patients receiving intrathecal chemotherapy were randomly assigned 1:1:1 to undergo bed rest for 6, 8, or 10 h after intrathecal chemotherapy. The primary outcome was the rate of complications after intrathecal chemotherapy. The analysis was per protocol.

Results

A total of 359 patients among the 390 patients in our study completed follow-up with 120 patients in the 6-h group, 120 in the 8-h group, and 119 in the 10-h group. The complications among the three groups differed significantly (P = 0.005). The 6-h group had significantly more complications than the 8- (50, 41.7% vs 29, 24.2%, P = 0.004) and 10-h groups (50, 41.7% vs 31, 26.1%, P = 0.011), whereas the difference between the 8- and 10-h groups was not significant (29, 24.2% vs 31, 26.1%, P = 0.737).

Conclusions

The overall results support that the optimal time interval for bed rest in the supine position after intrathecal chemotherapy is 8 h. This trial is registered with the Chinese Clinical Trial Registry (number ChiCTR-IOR-17011671).

Imaging Performance of a Handheld Ultrasound System With Real-Time Computer-Aided Detection of Lumbar Spine Anatomy: A Feasibility Study

OBJECTIVES

The aim of this study was to evaluate the imaging performance of a handheld ultrasound system and the accuracy of an automated lumbar spine computer-aided detection (CAD) algorithm in the spines of human subjects.

MATERIALS AND METHODS

This study was approved by the institutional review board of the University of Virginia. The authors designed a handheld ultrasound system with enhanced bone image quality and fully automated CAD of lumbar spine anatomy. The imaging performance was evaluated by imaging the lumbar spines of 68 volunteers with body mass index between 18.5 and 48 kg/m. The accuracy, sensitivity, and specificity of the lumbar spine CAD algorithm were assessed by comparing the algorithm's results to ground-truth segmentations of neuraxial anatomy provided by radiologists.

RESULTS

The lumbar spine CAD algorithm detected the epidural space with a sensitivity of 94.2% (95% confidence interval [CI], 85.1%-98.1%) and a specificity of 85.5% (95% CI, 81.7%-88.6%) and measured its depth with an error of approximately ±0.5 cm compared with measurements obtained manually from the 2-dimensional ultrasound images. The spine midline was detected with a sensitivity of 93.9% (95% CI, 85.8%-97.7%) and specificity of 91.3% (95% CI, 83.6%-96.9%), and its lateral position within the ultrasound image was measured with an error of approximately ±0.3 cm. The bone enhancement imaging mode produced images with 5.1- to 10-fold enhanced bone contrast when compared with a comparable handheld ultrasound imaging system.

CONCLUSIONS

The results of this study demonstrate the feasibility of CAD for assisting with real-time interpretation of ultrasound images of the lumbar spine at the bedside.

Epidemiological surveillance of herpes viral encephalitis in Cordoba, Colombia

Objective To establish an epidemiological surveillance of viral herpes encephalitis in major hospitals of Monteria, Cordoba. Methods From September 2009 to December 2011, a descriptive study of cases of viral encephalitis was made in three hospitals in the city of Monteria. Cerebrospinal fluid (CSF) samples from 118 patients were included in the study. Clinical aspects, as well as cytochemical and microbiological analysis (Gram stain and culture) of CSF, were used for selecting the patients. Virus detection was performed by using multiplex nested PCR for Herpes simplex virus 1 and 2, Epstein Barr virus, Cytomegalovirus and Varicella zoster virus. Results Viral DNA of herpesvirus was detected in the CSFs of 30 (25.4 %) participants, as follows: 22 (18.6 %) Herpes simplex 1 and 2 viruses, 4 (3.3 %) Cytomegalovirus and 1 (0.8 %) Varicella zoster virus. Co-infections were observed in 3 patients (2.5 %), 1 case by HSV-VZV and 2 cases by CMV/HSV. The clinical manifestations of the patients included: headache (18.6 %), fever (14.4 %), asthenia (10.1 %), seizures (9.3 %), vomiting (8.4 %), and stiff neck (5.9 %). Thirty percent of the patients also had HIV-AIDS. A case fatality rate of 20 % was observed for the patients. Conclusions This paper shows that herpesvirus is a cause of infection of the CNS in patients from Cordoba. This study contributes to the epidemiology of encephalitis, as well as to patient management.

The blood-brain barrier in psychosis

Blood-brain barrier pathology is recognised as a central factor in the development of many neurological disorders, but much less is known about the role of the blood-brain barrier in psychiatric disorders. We review post-mortem, serum-biomarker, CSF-biomarker, and neuroimaging studies that have examined blood-brain barrier structure and function in schizophrenia and related psychoses. We consider how blood-brain barrier dysfunction could relate to glutamatergic and inflammatory abnormalities, which are increasingly understood to play a part in the pathogenesis of psychosis. Mechanisms by which the blood-brain barrier and its associated solute transporters moderate CNS availability of antipsychotic drugs are summarised. We conclude that the complex nature of blood-brain barrier dysfunction in psychosis might be relevant to many aspects of disrupted neuronal and synaptic function, increased permeability to inflammatory molecules, disrupted glutamate homoeostasis, impaired action of antipsychotics, and development of antipsychotic resistance. Future research should address the longitudinal course of blood-brain barrier alterations in psychosis, to determine whether blood-brain barrier dysfunction is a cause or consequence of the pathology associated with the disorder.

A user's guide for α-synuclein biomarker studies in biological fluids: Perianalytical considerations

Parkinson's disease biomarkers are needed to increase diagnostic accuracy, to objectively monitor disease progression and to assess therapeutic efficacy as well as target engagement when evaluating novel drug and therapeutic strategies. This article summarizes perianalytical considerations for biomarker studies (based on immunoassays) in Parkinson's disease, with emphasis on quantifying total α‐synuclein protein in biological fluids. Current knowledge and pitfalls are discussed, and selected perianalytical variables are presented systematically, including different temperature of sample collection and types of collection tubes, gradient sampling, the addition of detergent, aliquot volume, the freezing time, and the different thawing methods. We also discuss analytical confounders. We identify gaps in the knowledge and delineate specific areas that require further investigation, such as the need to identify posttranslational modifications of α‐synuclein and antibody‐independent reference methods for quantification, as well as the analysis of potential confounders, such as comorbidities, medication, and phenotypes of Parkinson's disease in larger cohorts. This review could be used as a guideline for future Parkinson's disease biomarker studies and will require regular updating as more information arises in this growing field, including new technical developments as they become available. In addition to reviewing best practices, we also identify the current technical limitations and gaps in the knowledge that should be addressed to enable accurate and quantitative assessment of α‐synuclein levels in the clinical setting. © 2017 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Consensus guidelines for lumbar puncture in patients with neurological diseases

Introduction

Cerebrospinal fluid collection by lumbar puncture (LP) is performed in the diagnostic workup of several neurological brain diseases. Reluctance to perform the procedure is among others due to a lack of standards and guidelines to minimize the risk of complications, such as post-LP headache or back pain.

Methods

We provide consensus guidelines for the LP procedure to minimize the risk of complications. The recommendations are based on (1) data from a large multicenter LP feasibility study (evidence level II-2), (2) systematic literature review on LP needle characteristics and post-LP complications (evidence level II-2), (3) discussion of best practice within the Joint Programme Neurodegenerative Disease Research Biomarkers for Alzheimer's disease and Parkinson's Disease and Biomarkers for Multiple Sclerosis consortia (evidence level III).

Results

Our consensus guidelines address contraindications, as well as patient-related and procedure-related risk factors that can influence the development of post-LP complications.

Discussion

When an LP is performed correctly, the procedure is well tolerated and accepted with a low complication rate.

Cerebrospinal fluid lens-free microscopy: a new tool for the laboratory diagnosis of meningitis

Cerebrospinal fluid cytology is performed by operator-dependant light microscopy as part of the routine laboratory work-flow diagnosis of meningitis. We evaluated operator-independent lens-free microscopy numeration of erythrocytes and leukocytes for the cytological diagnosis of meningitis. In a first step, prospective optical microscopy counts of leukocytes done by five different operators yielded an overall 16.7% misclassification of 72 cerebrospinal fluid specimens in meningitis/non-meningitis categories using a 10 leukocyte/μL cut-off. In a second step, the lens-free microscopy algorithm adapted for counting cerebrospinal fluid cells and discriminating leukocytes from erythrocytes was modified step-by-step in the prospective analysis of 215 cerebrospinal fluid specimens. The definite algorithm yielded a 100% sensitivity and a 86% specificity compared to confirmed diagnostics. In a third step, a blind lens-free microscopic analysis of 116 cerebrospinal fluid specimens, including six cases of microbiology-confirmed infectious meningitis, yielded a 100% sensitivity and a 79% specificity. Adapted lens-free microscopy is thus emerging as an operator-independent technique for the rapid numeration of leukocytes and erythrocytes in cerebrospinal fluid. In particular, this technique is well suited to the rapid diagnosis of meningitis at point-of-care laboratories.

Neurologic Complications in the Intensive Care Unit

Complications involving the central and peripheral nervous system are frequently encountered in critically ill patients. All components of the neuraxis can be involved including the brain, spinal cord, peripheral nerves, neuromuscular junction, and muscles. Neurologic complications adversely impact outcome and length of stay. These complications can be related to underlying critical illness, pre-existing comorbid conditions, and commonly used and life-saving procedures and medications. Familiarity with the myriad neurologic complications that occur in the intensive care unit can facilitate their timely recognition and treatment. Additionally, awareness of treatment-related neurologic complications may inform decision-making, mitigate risk, and improve outcomes.

Longitudinal Metabolite Profiling of Cerebrospinal Fluid in Normal Pressure Hydrocephalus Links Brain Metabolism with Exercise-Induced VEGF Production and Clinical Outcome

Idiopathic normal pressure hydrocephalus is a neurological disease caused by abnormal cerebrospinal fluid flow and presents with symptoms such as dementia. Current therapy involves the removal of excess cerebrospinal fluid by shunting. Not all patients respond to this therapy and biomarkers are needed that could facilitate the characterization of patients likely to benefit from this treatment. Here, we measure brain metabolism in normal pressure hydrocephalus patients by performing a novel longitudinal metabolomic profiling study of cerebrospinal fluid. We find that the levels of brain metabolites correlate with clinical parameters, the amount of vascular endothelial growth factor in the cerebrospinal fluid, and environmental stimuli such as exercise. Metabolomic analysis of normal pressure hydrocephalus patients provides insight into changes in brain metabolism that accompany cerebrospinal fluid disorders and may facilitate the development of new biomarkers for this condition.

Neural Tissue Motion Impacts Cerebrospinal Fluid Dynamics at the Cervical Medullary Junction: A Patient-Specific Moving-Boundary Computational Model

Central nervous system (CNS) tissue motion of the brain occurs over 30 million cardiac cycles per year due to intracranial pressure differences caused by the pulsatile blood flow and cerebrospinal fluid (CSF) motion within the intracranial space. This motion has been found to be elevated in type 1 Chiari malformation. The impact of CNS tissue motion on CSF dynamics was assessed using a moving-boundary computational fluid dynamics (CFD) model of the cervical-medullary junction (CMJ). The cerebellar tonsils and spinal cord were modeled as rigid surfaces moving in the caudocranial direction over the cardiac cycle. The CFD boundary conditions were based on in vivo MR imaging of a 35-year old female Chiari malformation patient with ~150-300 µm motion of the cerebellar tonsils and spinal cord, respectively. Results showed that tissue motion increased CSF pressure dissociation across the CMJ and peak velocities up to 120 and 60%, respectively. Alterations in CSF dynamics were most pronounced near the CMJ and during peak tonsillar velocity. These results show a small CNS tissue motion at the CMJ can alter CSF dynamics for a portion of the cardiac cycle and demonstrate the utility of CFD modeling coupled with MR imaging to help understand CSF dynamics.

Determination of the role of injection site on the efficacy of intra-CSF enzyme replacement therapy in MPS IIIA mice

MPS IIIA is an inherited neurodegenerative lysosomal storage disorder characterized by cognitive impairment, sleep-wake cycle disturbance, speech difficulties, eventual mental regression and early death. Neuropathological changes include accumulation of heparan sulfate and glycolipids, neuroinflammation and degeneration. Pre-clinical animal studies indicate that replacement of the deficient enzyme, sulfamidase, via intra-cerebrospinal fluid (CSF) injection is a clinically-relevant treatment approach, reducing neuropathological changes and improving symptoms. Given that there are several routes of administration of enzyme into the CSF (intrathecal lumbar, cisternal and ventricular), determining the effectiveness of each injection strategy is crucial in order to provide the best outcome for patients. We delivered recombinant human sulfamidase (rhSGSH) to a congenic mouse model of MPS IIIA via each of the three routes. Mice were euthanized 24h or one-week post-injection; the distribution of enzyme within the brain and spinal cord parenchyma was investigated, and the impact on primary substrate levels and other pathological lesions determined. Both ventricular and cisternal injection of rhSGSH enable enzyme delivery to brain and spinal cord regions, with the former mediating large, statistically significant decreases in substrate levels and reducing microglial activation. The single lumbar CSF infusion permitted more restricted enzyme delivery, with no reduction in substrate levels and little change in other disease-related lesions in brain tissue. While the ventricular route is the most invasive of the three methods, this strategy may enable the widest distribution of enzyme within the brain, and thus requires further exploration.

Diffusion Efficiency and Bioavailability of Resveratrol Administered to Rat Brain by Different Routes: Therapeutic Implications

Resveratrol possesses anti-tumor activities against central nervous system (CNS) tumors in vitro but has not yet been used clinically due to its low bioavailability, particularly in the CNS. This study thus aimed to elucidate brain bioavailability of trans-resveratrol by monitoring brain concentrations and dwell times following administration of resveratrol through intragastric, intraperitoneal, external carotid artery/ECA and intrathecal routes. In parallel, we evaluated the biological responses of rat RG2 glioblastoma cells as well as RG2-formed rat intracranial glioblastomas treated with resveratrol via intrathecal administration. The results revealed that resveratrol was detected in rat brains except when administered systemically. Intrathecal administration of reseveratrol led to abundant apoptotic foci and increased staining of the autophagy proteins, LC-3 and Beclin-1 and shrinkage of the intracranial tumors. In conclusion, the BBB penetrability of resveratrol is remarkably increased by intracthecal administration. Regular short-term resveratrol treatments suppress growth and enhance autophagic and apoptotic activities of rat RG2 glioblastoma cells in vitro and in vivo. Therefore, intrathecal administration of resveratrol could be an optimal intervention approach in the adjuvant management of brain malignancies.

Circulating Biomarker Panels in Alzheimer's Disease

The early diagnosis of diseases frequently represents an important unmet clinical need supporting in-time treatment of pathologies. This also applies to neurodegenerative diseases such as Alzheimer's disease (AD), the most common form of dementia, estimated to affect millions of individuals worldwide. The respective diagnostic and prognostic markers, especially for the preclinical stages of AD, are expected to improve patients' outcome significantly. In the last decades, many approaches to detecting AD have been developed, including markers to discover changes in amyloid-β levels [from cerebrospinal fluid (CSF) or using positron emission tomography] or other brain imaging technologies such as structural magnetic resonance imaging (MRI), functional-connectivity MRI or task-related functional MRI. A major challenge is the detection of AD using minimally or even noninvasive biomarkers from body fluids such as plasma or serum. Circulating biomarker candidates based on mRNAs or proteins measured from blood cells, plasma or serum have been proposed for various pathologies including AD. As for other diseases, there is a tendency to use marker signatures obtained by high-throughput approaches, which allow the generation of profiles of hundreds to thousands of biomarkers simultaneously [microarrays, mass spectrometry or next-generation sequencing (NGS)]. Beyond mRNAs and proteins, recent approaches have measured small noncoding RNA (so-called microRNA) profiles in AD patients' blood samples using NGS or array-based technologies. Generally, the development of marker panels is in its early stages and requires further, substantial clinical validation. In this review, we provide an overview of different circulating AD biomarkers, starting with a brief summary of CSF markers and focusing on novel biomarker signatures such as small noncoding RNA profiles.

Haemostasis and safety measures before lumbar puncture in the haematology ward: the Danish routines

BACKGROUND/AIMS

Thrombocytopenia and the increasing use and variety of antithrombotic drugs is a challenge prior to lumbar puncture. This study examined the Danish haematology practice regarding drug pausation, assessment of haemostasis and whether fundoscopy is a routine safety measure.

METHODS

An online survey with questions pertaining to precautions of haemostasis and application of fundoscopy was sent by e-mail to all 12 haematology wards in Denmark.

RESULTS

Eleven sites participated. Five (45%) reported no pausation of antiplatelet drugs at all. The mean platelet limit prior to lumbar puncture was 50 × 10(9)/l (range 10-50 × 10(9)/l). Seven (64%) sites had an international normalised ratio limit of 1.5, and the remaining 4 had values between 1.0 and 2.5. Two (18%) reported occasional use of thromboelastography or platelet analysis to assess the bleeding risk. Fundoscopy is routinely performed in 4 (36%) departments.

CONCLUSION

We report considerable variation in the routine handling of antithrombotics and thrombocytopenia in patients set for lumbar puncture in Danish haematology departments. The diversity may be explained by and related to different opinions in the literature. Common national guidelines are warranted and there is a need for studies to establish an evidence-based approach for the management of patients at risk of bleeding when lumbar puncture or another invasive procedure is indicated.

In-depth characterization of the cerebrospinal fluid (CSF) proteome displayed through the CSF proteome resource (CSF-PR)

In this study, the human cerebrospinal fluid (CSF) proteome was mapped using three different strategies prior to Orbitrap LC-MS/MS analysis: SDS-PAGE and mixed mode reversed phase-anion exchange for mapping the global CSF proteome, and hydrazide-based glycopeptide capture for mapping glycopeptides. A maximal protein set of 3081 proteins (28,811 peptide sequences) was identified, of which 520 were identified as glycoproteins from the glycopeptide enrichment strategy, including 1121 glycopeptides and their glycosylation sites. To our knowledge, this is the largest number of identified proteins and glycopeptides reported for CSF, including 417 glycosylation sites not previously reported. From parallel plasma samples, we identified 1050 proteins (9739 peptide sequences). An overlap of 877 proteins was found between the two body fluids, whereas 2204 proteins were identified only in CSF and 173 only in plasma. All mapping results are freely available via the new CSF Proteome Resource (http://probe.uib.no/csf-pr), which can be used to navigate the CSF proteome and help guide the selection of signature peptides in targeted quantitative proteomics.

A practical approach to, diagnosis, assessment and management of idiopathic intracranial hypertension

Adult patients who present with papilloedema and symptoms of raised intracranial pressure need urgent multidisciplinary assessment including neuroimaging, to exclude life-threatening causes. Where there is no apparent underlying cause for the raised intracranial pressure, patients are considered to have idiopathic intracranial hypertension (IIH). The incidence of IIH is increasing in line with the global epidemic of obesity. There are controversial issues in its diagnosis and management. This paper gives a practical approach to assessing patients with papilloedema, its investigation and the subsequent management of patients with IIH.

Bone marrow elements in cerebrospinal fluid: Review of literature with a case study

Presence of bone marrow elements in cerebrospinal fluid is rare. Journal publications on this topic are few and majority of them were written over a decade ago mostly as case reports in young children or the elderly. The increased cellularity and presence of myeloid precursors can be a pitfall and may be misdiagnosed as leukemia or lymphoma or central nervous system infection, when the specimen is actually not representative. With the intention to create awareness of potential pitfalls and avoid erroneous diagnoses, as well as adding on to the current photo archive of bone marrow elements in CSF, we present a recent case of bone marrow contaminants in the CSF of a 16-year-old girl.

Pediatric lumbar puncture and cerebrospinal fluid analysis

BACKGROUND

Lumbar puncture (LP) is a commonly performed procedure in pediatrics. Accurate analysis of cerebrospinal fluid (CSF) profile is essential in diagnosing and managing a variety of infectious and inflammatory conditions involving the brain, meninges, and spinal cord. It can also provide useful diagnostic information in the evaluation of possible subarachnoid hemorrhage and demyelinating syndromes, and aid in the diagnosis and management of pseudotumor cerebri.

OBJECTIVES

To review anatomic, physiologic, and pathologic aspects of performing pediatric lumbar puncture and CSF analysis.

DISCUSSION

Although still a commonly performed procedure in the outpatient setting, effective vaccines to prevent invasive infection due to Streptococcus pneumoniae and Haemophilus influenzae type b have greatly reduced pediatric bacterial meningitis rates due to these pathogens, resulting in decreased opportunity for physician-trainees to perfect this important skill (among nonneonates) during the 3 years of supervised residency training. Success in performing pediatric LP is augmented by a thorough understanding of medical aspects related to this procedure. This article discusses technical aspects involved in successfully performing a lumbar puncture to obtain CSF, and interpreting a CSF profile in children.

CONCLUSION

A thorough understanding of anatomic, physiologic, and pathologic considerations regarding performing lumbar puncture and CSF analysis can augment success in diagnosing a variety of potentially serious pediatric conditions.

[Current cerebrospinal fluid diagnostics for pathogen-related diseases]

Cerebrospinal fluid (CSF) analysis is of utmost importance to establish an early diagnosis of central nervous system (CNS) infections and to start appropriate therapy. The CSF white cell count, lactate concentration and total protein levels are usually available very quickly even from non-specialized laboratories and the combination of these parameters often provides sufficient information for decision-making in emergency cases. It is, however, not always possible to identify the underlying infective agent despite further CSF analyses, such as bacterial and fungal staining, evaluation of the blood-CSF barrier function, intrathecal immunoglobulin synthesis and oligoclonal IgG bands. Therefore, close communication between the laboratory and the clinician is an important prerequisite to specify additional pathogen-related diagnostic measures for successful confirmation of the diagnosis.

Controlled release of simvastatin from in situ forming hydrogel triggers bone formation in MC3T3-E1 cells

Simvastatin (SIM), a drug commonly administered for the treatment of hypercholesterolemia, has been recently reported to induce bone regeneration/formation. In this study, we investigated the properties of hydrogel composed of gelatin-poly(ethylene glycol)-tyramine (GPT) as an efficient SIM delivery vehicle that can trigger osteogenic differentiation. Sustained delivery of SIM was achieved through its encapsulation in an injectable, biodegradable GPT-hydrogel. Cross-linking of the gelatin-based GPT-hydrogel was induced by the reaction of horse radish peroxidase and H(2)O(2). GPT-hydrogels of three different matrix stiffness, 1,800 (GPT-hydrogel1), 5,800 (GPT-hydrogel2), and 8,400 Pa (GPT-hydrogel3) were used. The gelation/degradation time and SIM release profiles of hydrogels loaded with two different concentrations of SIM, 1 and 3 mg/ml, were also evaluated. Maximum swelling times of GPT-hydrogel1, GPT-hydrogel2, and GPT-hydrogel3 were observed to be 6, 12, and 20 days, respectively. All GPT-hydrogels showed complete degradation within 55 days. The in vitro SIM release profiles, investigated in PBS buffer (pH 7.4) at 37°C, exhibited typical biphasic release patterns with the initial burst being more rapid with GPT-hydrogel1 compared with GPT-hydrogel3. Substantial increase in matrix metalloproteinase-13, osteocalcin expression levels, and mineralization were seen in osteogenic differentiation system using MC3T3-E1 cells cultured with GPT-hydrogels loaded with SIM in a dose-dependent manner. This study demonstrated that controlled release of SIM from a biodegradable, injectable GPT-hydrogel had a promising role for long-term treatment of chronic degenerative diseases such as disc degenerative disease.

Will posttranslational modifications of brain proteins provide novel serological markers for dementias?

Drug development for dementias is significantly hampered by the lack of easily accessible biomarkers. Fluid biomarkers of dementias provide indications of disease stage, but have little prognostic value, cannot detect early pathological changes, and can only be measured in CSF (cerebrospinal fluid) which significantly limits their applicability. In contrast, imaging based biomarkers can provide indications of probability of disease progression, yet are limited in applicability due to cost, radiation and radio-tracers. These aspects highlight the need for other approaches to the development of biomarkers of dementia, which should focus on not only providing information about pathological changes, but also on being measured easily and reproducibly. For other diseases, focus on development of assays monitoring highly specific protease-generated cleavage fragments of proteins has provided assays, which in serum or plasma have the ability to predict early pathological changes. Proteolytic processing of brain proteins, such as tau, APP, and α-synuclein, is a key pathological event in dementias. Here, we speculate that aiming biomarker development for dementias at detecting small brain protein degradation fragments of generated by brain-derived proteases specifically in blood samples could lead to the development of novel markers of disease progression, stage and importantly of treatment efficacy.