Common infectious diseases of the central nervous system-clinical features and imaging characteristics

Definition, diagnosis and classification of infection-related movement disorders: Consensus proposal

BACKGROUND

Infection-related movement disorders (IRMD) present a complex diagnostic challenge due to the broad phenotypic spectrum, the variety of possible infectious aetiologies, and the complicated underlying mechanisms. Yet, a comprehensive framework for classifying IRMD is lacking.

METHODS

An international consensus panel under the directives of the Movement Disorders Society Infection-Related Movement Disorders Study Group developed a comprehensive definition and a consensus classification system. Case scenarios were used for validation.

RESULTS

A definition for IRMD and a two-axis-based classification system consisting of six descriptors are proposed, intended as tools for researchers and clinicians. Collected information on clinical characteristics, investigational findings, the infectious organism and presumed pathogenesis facilitate the evaluation of diagnostic certainty.

CONCLUSION

The proposed framework will serve for optimised diagnostic algorithms, systematic aggregation of informative datasets across studies, and ultimately improved care and outcome of patients with IRMDs.

Development of a Diagnostic Model for Differentiating Tuberculous Spondylitis and Pyogenic Spondylitis With MRI: A Multicenter Retrospective Observational Study

STUDY DESIGN

Multicenter retrospective observational study.

OBJECTIVE

This study aimed to distinguish tuberculous spondylitis (TS) from pyogenic spondylitis (PS) using magnetic resonance imaging (MRI). Further, a novel diagnostic model for differential diagnosis was developed.

SUMMARY OF BACKGROUND DATA

TS and PS are the two most common spinal infections. Distinguishing between these types clinically is challenging. Delayed diagnosis can lead to deficits or kyphosis. Currently, there is a lack of radiology-based diagnostic models for TS and PS.

METHODS

We obtained radiologic images from MRI imaging of patients with TS and PS and applied the least absolute shrinkage and selection operator regression to select the optimal features for a predictive model. Predictive models were built using multiple logistic regression analysis. Clinical utility was determined using decision curve analysis, and internal validation was performed using bootstrap resampling.

RESULTS

A total of 201 patients with TS (n=105) or PS (n=96) were enrolled. We identified significant differences in MRI features between both groups. We found that noncontiguous multivertebral and single-vertebral body involvement were common in TS and PS, respectively. Vertebral bone lesions were more severe in the TS group than in the PS group (Z=-4.553, P <0.001). The patients in the TS group were also more prone to vertebral intraosseous, epidural, and paraspinal abscesses ( P <0.001). A total of 8 predictors were included in the diagnostic model. Analysis of the calibration curve and area under the receiver operating characteristic curve suggested that the model was well-calibrated with high prediction accuracy.

CONCLUSIONS

This is the largest study comparing MRI features in TS and PS and the first to develop an MRI-based nomogram, which may help clinicians distinguish between TS and PS.

Neuromyelitis Optica Spectrum Disorder

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune condition characterized by recurrent episodes of optic neuritis (ON) and transverse myelitis. This case report aims to highlight the importance of considering atypical presentations of NMOSD when confronted with MRI-detected Wernicke's encephalopathy. The primary target in NMOSD is the aquaporin-4 (AQP4) protein, predominantly located on astrocyte surfaces. Antibodies binding to AQP4 can lead to astrocyte dysfunction and damage, contributing to NMOSD's distinctive pathology. The associated immune response and inflammation can cause secondary harm to various components of the central nervous system, including oligodendrocytes and neuronal axons. This inflammatory process results in perivascular demyelination and axonal injury, further aggravating neurological deficits in NMOSD. In this case, we present a 39-year-old female with no prior medical or surgical history who sought medical attention due to a three-week history of progressive eyelid heaviness and somnolence. NMOSD is an autoimmune condition primarily targeting the AQP4 protein, resulting in recurrent ON and transverse myelitis. The patient was initially misdiagnosed with myasthenia gravis due to somnolence and ptosis. Due to concerns about myasthenia gravis due to diffuse fatigue and bilateral ptosis, the patient was initially treated with intravenous immunoglobulin (IVIG) and admitted to the neurology service. On the first day of her hospitalization, MRI with and without contrast revealed extensive, non-enhancing T2-weighted-fluid-attenuated inversion recovery (T2-FLAIR) hyperintensities surrounding the third ventricle and affecting the periaqueductal grey, medial thalami, and mammillary bodies. There was also an interval increase in T2-FLAIR hyperintensity within the right medial temporal lobe, extending more posteriorly and inferiorly, abutting the temporal horn. Subsequent CSF encephalitis panel results showed positive West Nile virus (WNV) IgG but negative WNV IgM, and AQP4 antibodies were positive. Given the high specificity of AQP4 antibodies, the patient was diagnosed with neuromyelitis optica (NMO) encephalitis. This case underscores the importance of considering atypical presentations of NMO when confronted with MRI-detected Wernicke's encephalopathy. Since our patient primarily displayed somnolence and eye-related symptoms, neither NMO nor Wernicke's encephalopathy were initially considered in the differential diagnosis. Furthermore, despite MRI findings suggestive of Wernicke's encephalopathy, it was considered less likely due to the absence of thiamine deficiency and consistent denials by family members regarding alcohol use, gastrointestinal issues, or inadequate oral intake. This case underscores the importance of considering NMOSD in patients with atypical symptoms, even when initial presentations suggest other conditions. Timely diagnosis is crucial to prevent mismanagement and improve patient outcomes. Clinicians should maintain a high level of suspicion for NMOSD, especially when MRI findings do not align with the initial diagnosis, as early recognition and treatment can significantly impact patient care and prognosis.

Convergence of Artificial Intelligence and Neuroscience towards the Diagnosis of Neurological Disorders-A Scoping Review

Artificial intelligence (AI) is a field of computer science that deals with the simulation of human intelligence using machines so that such machines gain problem-solving and decision-making capabilities similar to that of the human brain. Neuroscience is the scientific study of the struczture and cognitive functions of the brain. Neuroscience and AI are mutually interrelated. These two fields help each other in their advancements. The theory of neuroscience has brought many distinct improvisations into the AI field. The biological neural network has led to the realization of complex deep neural network architectures that are used to develop versatile applications, such as text processing, speech recognition, object detection, etc. Additionally, neuroscience helps to validate the existing AI-based models. Reinforcement learning in humans and animals has inspired computer scientists to develop algorithms for reinforcement learning in artificial systems, which enables those systems to learn complex strategies without explicit instruction. Such learning helps in building complex applications, like robot-based surgery, autonomous vehicles, gaming applications, etc. In turn, with its ability to intelligently analyze complex data and extract hidden patterns, AI fits as a perfect choice for analyzing neuroscience data that are very complex. Large-scale AI-based simulations help neuroscientists test their hypotheses. Through an interface with the brain, an AI-based system can extract the brain signals and commands that are generated according to the signals. These commands are fed into devices, such as a robotic arm, which helps in the movement of paralyzed muscles or other human parts. AI has several use cases in analyzing neuroimaging data and reducing the workload of radiologists. The study of neuroscience helps in the early detection and diagnosis of neurological disorders. In the same way, AI can effectively be applied to the prediction and detection of neurological disorders. Thus, in this paper, a scoping review has been carried out on the mutual relationship between AI and neuroscience, emphasizing the convergence between AI and neuroscience in order to detect and predict various neurological disorders.

Middle meningeal artery embolisation: The review of a new treatment for chronic subdural hematomas

Background

This is a literature review aiming to provide an update about the recent findings related to the efficacy of middle meningeal artery embolization (MMAE) in the treatment of chronic subdural hematomas (cSDHs), comparison with conventional therapy and deduction of the current recommendations and indications.

Methods

The literature is reviewed using a search through the PubMed index using keywords. Studies are then screened, skimmed, and thoroughly read. 32 studies fulfilled the inclusion criteria and are included in the study.

Results

Five indications for the application of MMA embolization (MMAE) are deducted from the literature. The usage as a preventive measure after surgical treatment of symptomatic cSDHs in patients with a high risk of recurrence and the usage as a standalone procedure has been the most common reasons for indication of this procedure. Rates of failures for the aforementioned indications have been 6.8% and 3.8%, respectively.

Conclusion

The safety of MMAE as a procedure is regarded as a general theme in the literature and can be considered for future applications. Usage of this procedure in clinical trials with more patient segregation and timeframe assessment relative to surgical intervention are recommendations of this literature review.

Role of MRI modalities in assessment of cystic brain Lesions: a prospective study

Background. Intracranial cystic lesions are unnatural cavities in which the continuity of the brain parenchyma is disrupted because of different pathologies such as infections and tumors containing proteinaceous fluid and/or cellular/necrotic materials. Purpose – to investigate the value of some MRI modalities, mostly DWI and MR spectroscopy, in differentiation of the common intracranial intra-axial cystic brain lesions to help these patients benefit from the best medical management and treatment. Materials and Methods. This is a prospective study, conducted from April 2019 till April 2021. It involved forty adult patients of both sexes with a cystic/necrotic intra-axial brain lesion with variable perifocal edema and rim enhancement on post-contrast study at MRI unit, radiology department, Ain Shams University (ASU) Hospital. All examinations were carried out after signing of the informed consent by the patients themselves or their guardian if the patient was incapacitated by any means. Results. The ADC values in the center of lesions were not uniform. We found the lowest ADC value in the center of the lesion at the abscess 0.4x10–3 mm2 /s, and the highest ADC value 3.2x10–3 mm2 /s was in cystic neoplastic lesion. There was a significant difference in the ADC values in the center of neoplastic necrotic lesions; mean ADC value was (1.95±1.08) x10–3 mm2 /s and (1.15±0.65) x10–3 mm2 /s in abscess lesions, with a cut-off value, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy value of: 1.55%, 92.9%, 91.7%, 96.3%, 84.6% and 92.5% respectively. MRS was performed in 40 cases, and the Cho/Cr, Cho/NAA and NAA/Cr mean ratios were calculated. These ratios were compared between the different categories. Statistically significant differences were found in the Cho/Cr, Cho/NAA ratios between both groups (p values<0.001**), while no statistically significant difference was found in the NAA/Cr ratio. Conclusion. Diffusion-weighted imaging (DWI) and magnetic resonance spectroscopy (MRS) are useful as additional diagnostic modalities for differentiating brain abscesses from cystic or necrotic brain tumors. Furthermore, the following MR techniques may be helpful for discriminating brain abscess from cystic or necrotic tumors: diffusion tensor imaging (DTI), perfusion weighted imaging as well as positron emission tomography computed tomography (PET-CT). This will help to improve the accuracy of MR in differentiating brain abscess from cystic or necrotic tumors.

Viral aetiology of acute central nervous system infections in children, Iran

Introduction. Viral infections are increasingly an important cause of central nervous system (CNS) complications.

Hypothesis/Gap Statement. There is no comprehensive insight about CNS infections due to viral agents among Iranian children.

Aim. This study aimed to investigate the viral aetiology, clinical and epidemiological profile of children with acute infections of the CNS.

Methodology. A prospective study was conducted on children at the referral hospital in Isfahan, Iran, from June 2019 to June 2020. A multiplex PCR assay was used to detect the viral causative agent in cerebrospinal fluid and throat/rectal swab samples.

Results. Among 103 patients with eligible criteria, a confirmed or probable viral aetiology was detected in 41 (39.8 %) patients, including enteroviruses – 56.1 %, herpes simplex virus 1/2 (HSV-1/2) – 31.7 %, Epstein-Barr virus – 17.1 %, varicella-zoster virus (VZV) – 9.7 %, influenza A virus (H1N1) –4.9 % and mumps – 2.4 %. There was a higher proportion of PCR-positive samples in infants than in other age groups. Encephalitis and meningoencephalitis were diagnosed in 68.3 % (28/41) and 22 % (9/41) PCR-positive cases, respectively.

Conclusion. The findings of this research provide insights into the clinical and viral aetiological patterns of acute CNS infections in Iran, and the importance of molecular methods to identify CNS viruses. HSV and VZV were identified as important causes of encephalitis in young children.

Understanding global changes of the mouse brain proteome after vaginal infection with HSV-2 using a label-free shotgun approach

Herpes simplex virus type 2 (HSV-2) is a common human pathogen that establishes lifelong latency in neurons of the nervous system. The number of severe central nervous system infections caused by the virus has increased recently. However, the pathogenesis of HSV-2 infection in the nervous system is not fully understood. Here, we demonstrated global proteomic changes in the brain tissue in BALB/c mice vaginally infected with HSV-2. Data are available via ProteomeXchange with identifier PXD034186. A total of 249 differentially expressed proteins were identified in infected brain tissue. The GO and KEGG enrichment analysis of these proteins indicated that they were mainly involved in the regulation of synapse formation and synaptic excitability. In addition, genes affecting autophagy, the development of other neurodegenerative diseases, and signaling pathways relevant to other neurologic diseases were identified. Additional experiments, comparing the brain tissue of asymptomatic and symptomatic mice showed a differential expression of proteins involved in synapse formation and synaptic transmission. Others were involved in autophagy, addiction, and signaling pathways of other neurologic diseases. These results suggest that changes in synaptic structure and function, as well as autophagy, may be related to the development of neurologic abnormalities that follow HSV-2 infection. We also identified a protein GluN2A encoded by Grin2a was continuously expressed at high levels after infection. We propose that GluN2A may be a key molecule in the pathogenesis of HSV-2-induced neurologic diseases.

Brain abscess in immunocompetent patients: recent findings

PURPOSE OF REVIEW

We conducted a systematic review of the literature to update findings on the epidemiology and the management of cerebral abscesses in immunocompetent patients.

RECENT FINDINGS

Observational studies suggest that the overall prognosis has improved over the last decades but mortality rates remain high. Several parameters may contribute to a better prognosis, including the identification of common risk factors for brain abscess, the systematic use of brain MRI at diagnosis, the implementation of appropriate neurosurgical and microbiological techniques for diagnosis, the optimization of the antibacterial treatment based on epidemiology and pharmacokinetic/pharmacodynamic studies, and a long-term follow-up for detection of secondary complications. Outcome research on brain abscess is mainly based on observational studies. Randomized controlled trials have yet to be performed to identify clinically relevant interventions associated with improved patient-centered outcomes.

SUMMARY

Our review highlights the importance of a multidisciplinary approach to optimize brain abscess management both at the acute phase and in the long-term. Randomized controlled studies are urgently needed to identify interventions associated with improved outcomes.

Misdiagnosis of HIV With Toxoplasmosis Encephalopathy With Progressive Memory Loss as the Initial Symptom: A Case Report

Toxoplasmosis encephalopathy (TE) is a kind of encephalopathy parasitic disease caused by Toxoplasma gondii. It is the most common opportunistic for central system infection in patients with acquired immunodeficiency syndrome (AIDS) or human immunodeficiency virus. Without early diagnosis and proper treatment, this opportunistic infection can be life-threatening. The common clinical manifestations of the disease include altered mental state, epilepsy, cranial nerve damage, paresthesia, cerebellar signs, meningitis, motor disorders, and neuropsychiatry. The most common presentation in about 75% of cases is a subacute episode of focal neurological abnormalities such as hemiplegia, personality changes, or aphasia. Imaging needs to be differentiated from multiple sclerosis, lymphoma, and metastases. We report a case of acquired immune deficiency syndrome complicated with toxoplasma encephalopathy with rapid progressive memory loss as the initial symptom and misdiagnosed as multiple sclerosis. Through the comprehensive analysis of the clinical symptoms and imaging examination of this disease, we hope to enhance the confidence of clinicians in the diagnosis of this disease.