CSF Findings in Relation to Clinical Characteristics, Subtype, and Disease Course in Patients With Guillain-Barré Syndrome.

BACKGROUND AND OBJECTIVES: To investigate CSF findings in relation to clinical and electrodiagnostic subtypes, severity, and outcome of Guillain-Barré syndrome (GBS) based on 1,500 patients in the International GBS Outcome Study. METHODS: Albuminocytologic dissociation (ACD) was defined as an increased protein level (>0.45 g/L) in the absence of elevated white cell count (<50 cells/µL). We excluded 124 (8%) patients because of other diagnoses, protocol violation, or insufficient data. The CSF was examined in 1,231 patients (89%). RESULTS: In 846 (70%) patients, CSF examination showed ACD, which increased with time from weakness onset: ≤4 days 57%, >4 days 84%. High CSF protein levels were associated with a demyelinating subtype, proximal or global muscle weakness, and a reduced likelihood of being able to run at week 2 (odds ratio [OR] 0.42, 95% CI 0.25-0.70; p = 0.001) and week 4 (OR 0.44, 95% CI 0.27-0.72; p = 0.001). Patients with the Miller Fisher syndrome, distal predominant weakness, and normal or equivocal nerve conduction studies were more likely to have lower CSF protein levels. CSF cell count was <5 cells/µL in 1,005 patients (83%), 5-49 cells/µL in 200 patients (16%), and ≥50 cells/µL in 13 patients (1%). DISCUSSION: ACD is a common finding in GBS, but normal protein levels do not exclude this diagnosis. High CSF protein level is associated with an early severe disease course and a demyelinating subtype. Elevated CSF cell count, rarely ≥50 cells/µL, is compatible with GBS after a thorough exclusion of alternative diagnoses. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that CSF ACD (defined by the Brighton Collaboration) is common in patients with GBS.

Rapport de cas Mononuclear pleocytosis and meningoencephalitis caused by Listeria monocytogenes in an adult horse.

Clinical disease caused by infection with Listeria monocytogenes is rare in adult horses, and there is a paucity of ante-mortem clinicopathologic changes for this species reported in the literature. Confirmatory diagnosis is difficult and often requires post-mortem sampling of the brainstem. This report details a case of meningoencephalitis caused by Listeria monocytogenes in an adult American quarter horse gelding presenting with central neurologic signs. Pre-mortem analysis of the cerebrospinal fluid revealed a mononuclear, primarily lymphocytic, pleocytosis, which is a reported finding in other species with listeriosis. Post-mortem histopathologic changes of the brainstem were characteristic of listeriosis, and infection was confirmed with immunohistochemical labeling and bacterial culture. Key clinical message: Listeriosis should be included as a differential diagnosis in neurologic horses with mononuclear pleocytosis identified on cerebrospinal fluid analysis.

Pléocytose mononucléaire et méningo-encéphalite causées par Listeria monocytogenes chez un cheval adulte. La maladie clinique causée par une infection à L. monocytogenes est rare chez les chevaux adultes, et il y a peu de changements clinico-pathologiques ante-mortem rapportés dans la littérature pour cette espèce. Le diagnostic de confirmation est difficile et nécessite souvent un prélèvement post-mortem du tronc cérébral. Ce rapport détaille un cas de méningo-encéphalite causée par L. monocytogenes chez un hongre quarter horse américain adulte présentant des signes neurologiques centraux. L'analyse pré-mortem du liquide céphalo-rachidien a révélé une pléocytose mononucléaire, principalement lymphocytaire, qui est une trouvaille rapportée chez d'autres espèces atteintes de listériose. Les modifications histopathologiques post-mortem du tronc cérébral étaient caractéristiques de la listériose et l'infection a été confirmée par un marquage immunohistochimique et une culture bactérienne.Message clinique clé :La listériose doit être incluse comme diagnostic différentiel chez les chevaux avec signes neurologiques présentant une pléocytose mononucléaire identifiée lors de l'analyse du liquide céphalo-rachidien.(Traduit par Dr Serge Messier).

Diagnostic Model for Discrimination Between Tuberculous Meningitis and Bacterial Meningitis.

Background: The differential diagnosis between tuberculous meningitis (TBM) and bacterial meningitis (BM) remains challenging in clinical practice. This study aimed to establish a diagnostic model that could accurately distinguish TBM from BM. Methods: Patients with TBM or BM were recruited between January 2017 and January 2021 at Tongji Hospital (Qiaokou cohort) and Sino-French New City Hospital (Caidian cohort). The detection for indicators involved in cerebrospinal fluid (CSF) and T-SPOT assay were performed simultaneously. Multivariate logistic regression was used to create a diagnostic model. Results: A total of 174 patients (76 TBM and 98 BM) and another 105 cases (39 TBM and 66 BM) were enrolled from Qiaokou cohort and Caidian cohort, respectively. Significantly higher level of CSF lymphocyte proportion while significantly lower levels of CSF chlorine, nucleated cell count, and neutrophil proportion were observed in TBM group when comparing with those in BM group. However, receiver operating characteristic (ROC) curve analysis showed that the areas under the ROC curve (AUCs) produced by these indicators were all under 0.8. Meanwhile, tuberculosis-specific antigen/phytohemagglutinin (TBAg/PHA) ratio yielded an AUC of 0.889 (95% CI, 0.840-0.938) in distinguishing TBM from BM, with a sensitivity of 68.42% (95% CI, 57.30%-77.77%) and a specificity of 92.86% (95% CI, 85.98%-96.50%) when a cutoff value of 0.163 was used. Consequently, we successfully established a diagnostic model based on the combination of TBAg/PHA ratio, CSF chlorine, CSF nucleated cell count, and CSF lymphocyte proportion for discrimination between TBM and BM. The established model showed good performance in differentiating TBM from BM (AUC: 0.949; 95% CI, 0.921-0.978), with 81.58% (95% CI, 71.42%-88.70%) sensitivity and 91.84% (95% CI, 84.71%-95.81%) specificity. The performance of the diagnostic model obtained in Qiaokou cohort was further validated in Caidian cohort. The diagnostic model in Caidian cohort produced an AUC of 0.923 (95% CI, 0.867-0.980) with 79.49% (95% CI, 64.47%-89.22%) sensitivity and 90.91% (95% CI, 81.55%-95.77%) specificity. Conclusions: The diagnostic model established based on the combination of four indicators had excellent utility in the discrimination between TBM and BM.

Immunological effects of dimethyl fumarate treatment in blood and CSF of patients with primary progressive MS.

Dimethyl fumarate is an efficient therapy used widely in patients with relapsing-remitting multiple sclerosis (RRMS). However, lacking effect of treatment has recently been reported in patients with primary progressive MS (PPMS) (Højsgaard Chow et al., 2021). In order to further analyze the immunological treatment response we investigated the systemic and intrathecal immunological effects of dimethyl fumarate (DMF) treatment in 50 patients with PPMS who participated in a 48-week randomized controlled trial with dimethyl fumarate vs placebo. We found substantial systemic immunomodulatory effects of DMF treatment comparable with those observed in patients with RRMS. However, intrathecal effects were limited and restricted to CD4+ T cells presumably resulting in higher concentrations of intrathecal IL-7.

Cerebrospinal fluid culture-positive bacterial meningitis increases the risk for neurologic damage among neonates.

OBJECTIVE: This study aimed to compare the clinical features and outcomes of neonatal bacterial meningitis (NBM) between patients with positive and negative cerebrospinal fluid (CSF) cultures and determine the risk factors for CSF culture-positive NBM. METHODS: We retrospectively reviewed the medical records of all patients with NBM. Perinatal clinical data, laboratory results, and cranial radiographs were obtained. RESULTS: Among the 186 neonates who met the inclusion criteria. The risk factors for positive CSF culture results were analysed using multiple logistic regression. The multivariable logistic regression analysis showed that the possible risk factors of NBM with positive CSF culture in this study were: Length of fever [OR = 1.126; 95% CI (0.999-1.268)], Neurologic symptoms [OR = 3.043; 95% CI (1.164-7.959)], Cerebrospinal fluid protein [OR = 1.001; 95% CI (1.000-1.001)]. Cases of NBM with a longer duration of fever, more neurologic symptoms, and higher levels of CSF protein were more likely to demonstrate positive results on CSF culture. CONCLUSION: Cases of NBM with CSF culture-positive results were more likely to have severe clinical manifestations and develop more serious neurologic damage. Patients with NBM who have longer durations of fever, more neurologic symptoms, and higher levels of CSF protein were more likely to have CSF culture-positive results, who should be followed up more closely.Key MessageBacterial meningitis is clinically defined as a serious inflammation of meningitis, usually caused by a variety of bacterial infections that may leave sequelae and long-term complications and high mortality rates. Early diagnosis is often difficult, particularly when the patient has been treated with antimicrobials.

Electroencephalography as a Non-Invasive Biomarker of Alzheimer's Disease: A Forgotten Candidate to Substitute CSF Molecules?

Biomarkers for disease diagnosis and prognosis are crucial in clinical practice. They should be objective and quantifiable and respond to specific therapeutic interventions. Optimal biomarkers should reflect the underlying process (pathological or not), be reproducible, widely available, and allow measurements repeatedly over time. Ideally, biomarkers should also be non-invasive and cost-effective. This review aims to focus on the usefulness and limitations of electroencephalography (EEG) in the search for Alzheimer's disease (AD) biomarkers. The main aim of this article is to review the evolution of the most used biomarkers in AD and the need for new peripheral and, ideally, non-invasive biomarkers. The characteristics of the EEG as a possible source for biomarkers will be revised, highlighting its advantages compared to the molecular markers available so far.

Limbic encephalitis in a child with ovarian teratoma and influenza B. Case report and critical review of the history of autoimmune anti-N-methyl-d-aspartate receptor encephalitis.

We report the appearance of clinical symptoms and signs of N-methyl-d-Aspartate (NMDA) receptor encephalitis in a patient presenting just days after contraction of influenza B. The offending mature ovarian teratoma was identified and removed on the 10th day after the appearance of symptoms, with subsequent nearly complete resolution of symptoms over the subsequent 6 months. We provide a focused literature review of the clinical and pathophysiologic literature of anti-NMDA receptor encephalitis pertaining to influenza B virus and the pediatric population. Taken together, this study contributes to the pathophysiological understanding of anti-NMDA receptor encephalitis and aids clinicians in its early recognition and management.

Collection of cerebrospinal fluid in 50 adult healthy donkeys (Equus asinus): clinical complications, and cytological and biochemical constituents.

BACKGROUND: Diseases of the central nervous system are a well-recognized cause of morbidity and mortality in equine. Collection and analysis of cerebrospinal fluid (CSF) give information about the type and stage of degenerative and inflammatory diseases in central nervous system (CNS). The present research aimed to assess the clinical complications of CSF collections and to establish range values of cytological and biochemical parameters of CSF in adult healthy donkeys (Equus asinus). The CSF samples were collected from fifty healthy donkeys at the lumbosacral (LS) and atlanto-occipital (AO) sites. RESULTS: Hypothermia, tachycardia, ataxia and recumbency may develop post-puncture. Erythrocytes were noticed in 35 of 50 CSF samples. Total nucleated cell counts ranged from 0 to 6 cells/µL, and lymphocytes predominated the cells (61%). The concentration of glucose (1.2 to 5.3 mmol/L) was lower than that of serum (P < 0.05). The CSF sodium concentration (123 to 160 mmol/L) was approximately like that of serum, but potassium (1.5-3 mmol/L) was lower than that of serum (P < 0.01). Urea concentrations (1.1-2.9 mmol/L) were markedly lower than serum (P < 0.001). Concentrations of CSF total proteins, and albumin ranged from 0.1 to 0.6 g/dL, and from 0.002 to 0.013 g/dL, respectively. The albumin quotient ranged from 0.06 to 0.56. CONCLUSIONS: Transient hypothermia, tachycardia, ataxia and recumbency may develop as clinical complications of CSF puncture procedures. The collection site has no impact on the constituents in CSF. Furthermore, this study presented the range values for normal cytological and biochemical constituents of CSF in donkeys (Equus asinus) that can provide a basis in comparison when evaluating CSF from donkeys with neurologic diseases.

Immune cell compartmentalization for brain surveillance and protection.

For decades, it was commonly accepted that the brain is secluded from peripheral immune activity and is self-sufficient for its maintenance and repair. This simplistic perception was based on the presence of resident immune cells, the microglia, and barrier systems within the brain, and the assumption that the central nervous system (CNS) lacks lymphatic drainage. This view was revised with the discoveries that higher functions of the CNS, homeostasis and repair are supported by peripheral innate and adaptive immune cells. The findings of bone marrow-derived immune cells in specialized niches, and the renewed observation that a lymphatic drainage system exists within the brain, further contributed to this revised model. In this Review, we describe the immune niches within the brain, the contribution of professional immune cells to brain functions, the bidirectional relationships between the CNS and the immune system and the relevance of immune components to brain aging and neurodegenerative diseases.

Mitochondrial dysfunction associated with autophagy and mitophagy in cerebrospinal fluid cells of patients with delayed cerebral ischemia following subarachnoid hemorrhage.

Decreased mitochondrial membrane potential in cerebrospinal fluid (CSF) was observed in patients with subarachnoid hemorrhage (SAH) accompanied by delayed cerebral ischemia (DCI). However, whether abnormal mechanisms of mitochondria are associated with the development of DCI has not been reported yet. Under cerebral ischemia, mitochondria can transfer into the extracellular space. Mitochondrial dysfunction can aggravate neurologic complications. The objective of this study was to evaluate whether mitochondrial dysfunction might be associated with autophagy and mitophagy in CSF cells to provide possible insight into DCI pathogenesis. CSF samples were collected from 56 SAH patients (DCI, n = 21; and non-DCI, n = 35). We analyzed CSF cells using autophagy and mitophagy markers (DAPK1, BNIP3L, BAX, PINK1, ULK1, and NDP52) via qRT-PCR and western blotting of proteins (BECN1, LC3, and p62). Confocal microscopy and immunogold staining were performed to demonstrate the differentially expression of markers within dysfunctional mitochondria. Significant induction of autophagic flux with accumulation of autophagic vacuoles, increased expression of BECN1, LC3-II, and p62 degradation were observed during DCI. Compared to non-DCI patients, DCI patients showed significantly increased mRNA expression levels (2-ΔCt) of DAPK1, BNIP3L, and PINK1, but not BAX, ULK1, or NDP52. Multivariable logistic regression analysis revealed that Hunt and Hess grade ≥ IV (p = 0.023), DAPK1 (p = 0.003), and BNIP3L (p = 0.039) were related to DCI. Increased mitochondrial dysfunction associated with autophagy and mitophagy could play an important role in DCI pathogenesis.

Flow cytometric analysis of cerebrospinal fluid improves detection of leukaemic blasts in infants with acute lymphoblastic leukaemia.

Infants with acute lymphoblastic leukaemia (ALL) have a high frequency of central nervous system (CNS) involvement. Flow cytometric analysis of cerebrospinal fluid (CSF) was recently demonstrated to be a sensitive method for detecting CNS involvement in childhood ALL. In the present study, CSF from 14 infants was collected at routine lumbar punctures and analysed by multicolour flow cytometry. At initial diagnosis, leukaemic blasts were detected in CSF by flow cytometry in 11 patients (78·6%) compared to seven patients (50%) by cytospin. Larger studies are needed to determine if CSF flow cytometry has prognostic value in infant ALL.

Detection of meningoencephalitis caused by Listeria monocytogenes with ischemic stroke-like onset using metagenomics next-generation sequencing: A case report.

RATIONALE: Listeria monocytogenes (L. monocytogenes) is a compatible intracellular bacterial pathogen that can invade different mammalian cells and reach the central nervous system (CNS), leading to meningoencephalitis and brain abscesses. In the diagnosis of L. monocytogenes meningoencephalitis (LMM), conventional tests are often reported as negative due to antibiotic therapy or low bacterial content in cerebrospinal fluid. To date, prompt diagnosis and accurate treatment remain a challenge for patients with Listeria infections. PATIENT CONCERNS: Here, we report a case of a 64-year-old male diagnosed with LMM by using metagenomics next-generation sequencing (mNGS). DIAGNOSIS: LMM was confirmed by mNGS analysis of cerebrospinal fluid. INTERVENTIONS: The patient was treated with piperacillin and sensitive antibiotics. OUTCOMES: The patient could walk independently about 1 month after admission and was discharged from the hospital. LESSONS: This case highlights the value of mNGS in the diagnosis of LMM and emphasizes the inadequate sensitivity of conventional diagnostic methods for Listeria infection.

Microalgae-based photosynthetic strategy for oxygenating avascularised mouse brain tissue - An in vitro proof of concept study.

Hypoxic brain injury is a leading cause of loss of quality of life globally for which there are currently no effective treatments. There has been increasing interest in incorporating photosynthesising agents into hypoxic tissue as a mechanism for in situ oxygen delivery, independent of vascular perfusion. To date this has not been tested in the brain. The oxygen production capacity of Chlamydomonas reinhardtii microalgal cultures was measured in artificial cerebrospinal fluid (aCSF) in benchtop assays and in cortical slices in situ. Cortical slice function was quantified by measuring the length, frequency and amplitude of seizure-like event (SLE) activity - in conventionally oxygenated aCSF, C. reinhardtii cultures, unoxygenated and deoxygenated aCSF. The possibility of direct toxic algal effects was investigated by exposing slices to cultures for 5 h. An oxygen level of 25 mg.L-1 was achieved with C. reinhardtii in no-Mg aCSF. Slice SLE function was preserved in C. reinhardtii, without the need for supplemental oxygen. In contrast, functional parameters deteriorated in unoxygenated and deoxygenated aCSF. In the former, there was a 66% reduction in SLE frequency and a 37% reduction in event amplitude. In the latter, SLE activity ceased completely. No toxic algae effects were seen in slices exposed to cultures for 5 h. These results confirm that C. reinhardtii oxygenation of aCSF can sustain cortical network activity - without tissue toxicity for the normal lifespan of an acute cortical slice. This study shows promise for the concept of photosynthesis as a mechanism for providing oxygen to rescue ischaemic avascularised brain tissue.

Automated Analysis of Cerebrospinal Fluid Cells Using Commercially Available Blood Cell Analysis Devices-A Critical Appraisal.

The analysis of cells in the cerebrospinal fluid (CSF) is a routine procedure that is usually performed manually using the Fuchs-Rosenthal chamber and cell microscopy for cell counting and differentiation. In order to reduce the requirement for manual assessment, automated analyses by devices mainly used for blood cell analysis have been also used for CSF samples. Here, we summarize the current state of investigations using these automated devices and critically review their limitations. Despite technical improvements, the lower limit for reliable leukocyte counts in the CSF is still at approximately 20 cells/µL, to be validated depending on the device. Since the critical range for clinical decisions is in the range of 5-30 cells/µL this implies that cell numbers < 30/µL require a manual confirmation. Moreover, the lower limit of reliable erythrocyte detection by automated devices is at approximately 1000/µL. However, even low erythrocyte numbers may be of clinical importance. In contrast, heavily hemorrhagic samples from neurosurgery may be counted automatically at an acceptable precision more quickly. Finally, cell differentiation by automated devices provides only a rough orientation for lymphocytes, granulocytes and monocytes. Other diagnostically important cell types such as tumor cells, siderophages, blasts and others are not reliably detected. Thus, although the automation may give a gross estimate sufficient for the emergency room situation, each CSF requires a manual microscopy for cytological evaluation for the final report. In conclusion, although automated analysis of CSF cells may provide a first orientation of the cell profile in an individual sample, an additional manual cell count and a microscopic cytology are still required and represent the gold standard.

Characteristics of Central Nervous System (CNS) Involvement in Children With Non-Hodgkin's Lymphoma (NHL) and the Diagnostic Value of CSF Flow Cytometry in CNS Positive Disease.

OBJECTIVE: To investigate the characteristics of central nervous system (CNS) involvement in children with non-Hodgkin's lymphoma (NHL) and the value of flow cytometry (FC) in the diagnosis of CNS disease in pediatric NHL. METHODS: The data of 56 newly diagnosed pediatric NHL patients with CNS involvement (CNS+/mass, CNS+/palsy, CNS+/CSF) were analyzed. The proportions and formats of CNS disease in different pathological types were compared. In addition, FC and conventional cytology (CC) of cerebrospinal fluid (CSF) were carried out in 383 newly diagnosed NHL cases. RESULTS: A total of 383 children with NHL were enrolled. Among these patients, 56 (14.6%) were diagnosed with positive CNS involvement (CNS+), 33 had bulky disease (tumor diameter >10 cm), 32 had bone marrow invasion, 32 had lactate dehydrogenase levels >1000 U/L, and 25 had invasion of more than 4 organs at the time of diagnosis. There were 14 patients with T lymphoblastic lymphoma (T-LBL), 9 with B lymphoblastic lymphoma (B-LBL), 26 with Burkitt's lymphoma (BL), and 2 with Epstein-Barr virus-positive diffuse large B cell lymphoma (EBV + DLBCL). Among the 56 CNS+ patients, 35 were CSF-positive (CSF+); there were 2 patients who were CSF+ via CC detection and 35 who were CSF+ via FC detection. The difference between CC and FC was statistically significant (P < 0.01). In the T-LBL group, 14 patients were CNS+/CSF, and in the B-LBL group, 8 were CNS+/mass. In the BL group, 22 patients were CNS+/mass and 15 were CNS+/CSF. In the anaplastic large-cell lymphoma group, 5 patients were CNS+/mass. Nine of the 56 CNS+ patients had events. The 2-year overall survival rate was 87% ± 0.046%, and the 2-year event-free survival rate was 76.2% ± 0.07%. CONCLUSION: CNS+ diagnoses were more common in pediatric NHL patients with bulky disease and/or bone marrow involvement and/or involvement of more than 4 organs at the time of diagnosis, and they were also common in the EBV + DLBCL and BL groups. FC of CSF showed important clinical significance in the diagnosis of CNS disease in pediatric NHL patients, and it can be used to significantly improve the CNS+ detection rate.

Cytologic diagnosis of metastatic embryonal rhabdomyosarcoma in cerebrospinal fluid: A case report.

Rhabdomyosarcoma (RMS) originates from a differentiation block in muscle progenitors. Leptomeningeal metastasis is a rare but devastating complication of RMS which can be caused by dissemination of cancer cells in cerebrospinal fluid (CSF). Here, we present a 4-year-old female with RMS originating from the upper nasal wall. The following histologic and immunohistochemistry analyses combined with molecular testing analysis supported the diagnosis of embryonal rhabdomyosarcoma (ERMS). Results from CSF routine test, magnetic resonance imaging scans and CSF cytology indicated metastatic meningitis, thus confirming the diagnosis of metastatic ERMS in CSF. This is the first report to describe the clinical features of ERMS in CSF.

Cerebrospinal Fluid Analysis.

Cerebrospinal fluid (CSF) analysis is a diagnostic tool for many conditions affecting the central nervous system. Urgent indications for lumbar puncture include suspected central nervous system infection or subarachnoid hemorrhage. CSF analysis is not necessarily diagnostic but can be useful in the evaluation of other neurologic conditions, such as spontaneous intracranial hypotension, idiopathic intracranial hypertension, multiple sclerosis, Guillain-Barré syndrome, and malignancy. Bacterial meningitis has a high mortality rate and characteristic effects on CSF white blood cell counts, CSF protein levels, and the CSF:serum glucose ratio. CSF culture can identify causative organisms and antibiotic sensitivities. Viral meningitis can present similarly to bacterial meningitis but usually has a low mortality rate. Adjunctive tests such as CSF lactate measurement, latex agglutination, and polymerase chain reaction testing can help differentiate between bacterial and viral causes of meningitis. Immunocompromised patients may have meningitis caused by tuberculosis, neurosyphilis, or fungal or parasitic infections. Subarachnoid hemorrhage has a high mortality rate, and rapid diagnosis is key to improve outcomes. Computed tomography of the head is nearly 100% sensitive for subarachnoid hemorrhage in the first six hours after symptom onset, but CSF analysis may be required if there is a delay in presentation or if imaging findings are equivocal. Xanthochromia and an elevated red blood cell count are characteristic CSF findings in patients with subarachnoid hemorrhage. Leptomeningeal carcinomatosis can mimic central nervous system infection. It has a poor prognosis, and large-volume CSF cytology is diagnostic.

Cerebrospinal fluid analysis in dogs: Main patterns and prevalence of albuminocytological dissociation.

BACKGROUND: Albuminocytological dissociation (ACD) of the cerebrospinal fluid (CSF) is defined as an increased total protein concentration with normal total nucleated cell count. It is suspected to occur in diseases that alter the blood-brain barrier, increase the production of protein or obstruct the flow of CSF. The purposes of this study were to review the CSF analysis results of a large cohort of dogs with neurological conditions, to analyse the total prevalence of ACD and to describe which diseases have a higher prevalence of ACD. STUDY DESIGN AND METHODS: Medical records were retrospectively searched for dogs whom CSF was sampled from 2012-2019. Data collected included signalment, body weight, site of collection of the CSF, CSF analysis results, and final diagnosis. RESULTS: A total of 497 dogs met the inclusion criteria. ACD was identified in 16.5% (82/497) of dogs. The diseases with higher proportion of ACD were cranial nerve neuropathy (6/10; 60.0%), brain tumour (10/24; 41.7%), idiopathic vestibular disease (7/17; 41.2%) and brain vascular disease (4/13; 30.8%). CLINICAL SIGNIFICANCE: This study describes the CSF patterns of the most common neurological conditions in dogs, also characterizing, for the first time in dogs, the prevalence and causes of ACD, which was identified in 16.5% of the samples. The diseases with highest proportions of ACD were cranial nerve neuropathy, brain tumour, idiopathic vestibular disease and brain vascular disease.

A comparison of the analysis of 3 types of body fluids using the XN-350 hematology analyzer versus light microscopy assessment.

ABSTRACT: We evaluated the capacity of the XN-350 instrument to analyze 3 different types of body fluid samples under "body fluid mode."The performance of XN-350 was evaluated in terms of precision, carryover, limit of blank, limit of detection, limit of quantification, and linearity. Cell enumeration and differential data produced by the XN-350 were compared to manual chamber counting results in 63 cerebrospinal fluid (CSF), 51 ascitic fluid, and 51 pleural fluid (PF) samples. Comparisons between XN-350 versus Cytospin data were also performed in PF samples.The precision, carry-over, limit of blank, and linearity of the XN-350 were acceptable. The limits of detection for white blood cells (WBCs) and red blood cells were 1.0/µL, and 1,000.0/µL, respectively; the corresponding limits of quantitation (LOQs) were 5.0/µL and 2,000.0/µL, respectively. The XN-350's cell enumeration and differential counting correlated well with those of manual chamber counting for all 3 sample types (except for differential counting in CSF samples), particularly parameters involving monocytes (r = 0.33) and mononuclear cells (MO- body fluid [BF]; r = 0.26), as well as total cell (TC-BF) enumeration (r = 0.50) and WBC-BF (r = 0.50) in PF samples. The MO-BF in CSF samples differed significantly from manual chamber counting results, but neither TC-BF nor WBC-BF in PF samples did. The XN-350 also showed good correlations with Cytospin analyses for differential counting of neutrophils, lymphocytes, and monocytes in PF samples. The differential counting of eosinophils via the XN-350 and Cytospin were not significantly correlated, but the difference between them was not significant.The XN-350 is an acceptable alternative to manual fluid analysis. Samples with low cellularity around the LOQ should be checked manually. Moreover, manual differential counting should be performed on CSF samples, particularity those with low cell numbers.