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American Journal of Rhinology & Allergy Jul 2024Endoscopic sinus surgery (ESS) could significantly improve olfactory function among patients with chronic rhinosinusitis (CRS). This study aimed to perform a... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Endoscopic sinus surgery (ESS) could significantly improve olfactory function among patients with chronic rhinosinusitis (CRS). This study aimed to perform a meta-analysis to evaluate the effect of ESS on the olfactory bulb volume (OBV) among patients with CRS.
METHODS
A systemic search of PubMed, Medline, Embase, Web of Science, and other databases was conducted to identify studies assessing OBV changes in patients with CRS after ESS utilizing magnetic resonance imaging.
RESULTS
A total of four studies with 168 participants were included. Comparing the changes in OBV of patients with CRS before and after surgery within 3-6 months, the ESS significantly improved the overall OBV ( = 0.005, I= 66%), with the left OBV increased by 5.57mm ( = 0.84, I= 0%), and the right OBV increased by 8.63mm ( = 0.09, I= 53%). A difference in OBV persists between healthy controls and patients with CRS 3-6 months after ESS. The overall OBV of patients with CRS after ESS was significantly smaller than controls (mean difference = -3.84, = 0.04), with a mean difference of 4.13mm on the left side ( = 0.72, I= 0%), and a mean difference of 3.22mm on the right side ( = 0.0001, I= 89%).
CONCLUSIONS
ESS significantly increases the OBV among patients with CRS.
Topics: Sinusitis; Rhinitis; Humans; Olfactory Bulb; Chronic Disease; Endoscopy; Paranasal Sinuses; Magnetic Resonance Imaging; Treatment Outcome; Organ Size; Rhinosinusitis
PubMed: 38549395
DOI: 10.1177/19458924241241874 -
Phytomedicine : International Journal... May 2024Intranasal administration has been adopted in traditional medicine to facilitate access to the bloodstream and central nervous system (CNS). In modern medicine, nasal...
BACKGROUND
Intranasal administration has been adopted in traditional medicine to facilitate access to the bloodstream and central nervous system (CNS). In modern medicine, nasal drug delivery systems are valuable for disease treatment because of their noninvasiveness, good absorption, and fast-acting effects.
OBJECTIVE
This study aimed to systematically organize preclinical and clinical studies on intranasal herbal medicines to highlight their potential in drug development.
METHODS
A comprehensive search for literature until February 2023 was conducted on PubMed and the Web of Science. From the selected publications, we extracted key information, including the types of herbal materials, target diseases, intranasal conditions, methods of toxicity evaluation, main outcomes, and mechanisms of action, and performed quality assessments for each study.
RESULTS
Of the 45 studies, 13 were clinical and 32 were preclinical; 28 studies used herbal extracts, 9 used prescriptions, and 8 used natural compounds. The target diseases were rhinosinusitis, influenza, fever, stroke, migraine, insomnia, depression, memory disorders, and lung cancer. The common intranasal volumes were 8-50 µl in mice, 20-100 µl in rats, and 100-500 µl in rabbits. Peppermint oil, Ribes nigrum folium, Melia azedarach L., Elaeocarpus sylvestris, Radix Bupleuri, Da Chuan Xiong Fang, Xingnaojing microemulsion, and Ginsenoside Rb1 emerged as potential candidates for rapid intranasal therapy. The in vivo toxicity assessments were based on mortality, body weight, behavioral changes, mucociliary activity, histopathology, and blood tests. Most intranasal treatments were safe, except for Cyclamen europaeum, Jasminum sambac, Punica granatum L., and violet oil, which caused mild adverse effects. At lower doses, intranasal herbal treatments often show greater effects than oral administration. The actions of intranasal herbal medicine mainly involve regulating inflammation and neurotransmission, with the olfactory bulb and anterior cingulate cortex to be relevant brain regions.
CONCLUSION
Intranasal delivery of herbal materials holds promise for enhancing drug delivery efficacy and reducing treatment duration, offering a potential future perspective for developing intranasal therapies for various diseases.
Topics: Animals; Administration, Intranasal; Brain; Fever; Plant Extracts; Humans
PubMed: 38442431
DOI: 10.1016/j.phymed.2024.155484 -
International Journal of Infectious... Jan 2024Symptoms from SARS-CoV-2 infection can involve multiple organ systems. Several reviews discussed the neurologic involvement and neuroimaging findings in adults but...
OBJECTIVES
Symptoms from SARS-CoV-2 infection can involve multiple organ systems. Several reviews discussed the neurologic involvement and neuroimaging findings in adults but research on children is lacking. This study aimed to analyze the incidence of neurologic involvement in patients diagnosed with pediatric inflammatory multisystem syndrome temporally associated with COVID-19 (PIMS-TS) or multisystem inflammatory syndrome in children (MIS-C); and also to summarize current literature on possible neuroimaging findings in SARS-CoV-2 infected children.
METHODS
A literature search in six electronic databases was performed to retrieve case series, cohort studies, and cross-sectional studies on neurologic involvement in COVID-19 patients younger than 21 years of age published between December 2019 to September 2023, including COVID-19 patients.
RESULTS
A total of 2224 patients with MIS-C from 10 cohorts and cross-sectional studies suggested that neurologic involvement in these subsets ranges from 8.5% to 32.1%. Symptoms included acute encephalitis, seizures, stroke, cranial nerve palsy, nausea/vomiting, and intracranial hypertension. Neuroradiology findings of 114 children from 50 case reports included splenial or acute disseminated encephalomyelitis (ADEM)-like lesions, cytotoxic brain edema, autoimmune demyelinating diseases, ischemic stroke and arteritis, venous thrombosis, intracranial hemorrhage, meningitis, posterior reversible encephalopathy syndrome, anti-N-methyl-D-aspartate receptor autoimmune encephalitis, acute hemorrhagic leukoencephalitis, hydrocephalus, olfactory bulb atrophy, cerebellitis, and acute necrotizing encephalitis.
CONCLUSION
Radiologic findings of SARS-CoV-2 infection in the pediatric population are diverse. Neuroimaging studies should be considered in critically ill patients to rule out neurologic involvement and facilitate early interventions.
Topics: Adult; Humans; Child; COVID-19; SARS-CoV-2; Cross-Sectional Studies; Posterior Leukoencephalopathy Syndrome; Neuroimaging; Systemic Inflammatory Response Syndrome
PubMed: 37944584
DOI: 10.1016/j.ijid.2023.11.006 -
Journal of Neurology Nov 2023Coronavirus disease 2019 (COVID-19) has been associated with nervous system involvement, with more than one-third of COVID-19 patients experiencing neurological... (Review)
Review
BACKGROUND
Coronavirus disease 2019 (COVID-19) has been associated with nervous system involvement, with more than one-third of COVID-19 patients experiencing neurological manifestations. Utilizing a systematic review, this study aims to summarize brain MRI findings in COVID-19 patients presenting with neurological symptoms.
METHODS
Systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) checklist. The electronic databases of PubMed/MEDLINE, Embase, Scopus, and Web of Science were systematically searched for literature addressing brain MRI findings in COVID-19 patients with neurological symptoms.
RESULTS
25 publications containing a total number of 3118 COVID-19 patients with neurological symptoms who underwent MRI were included. The most common MRI findings and the respective pooled incidences in decreasing order were acute/subacute infarct (22%), olfactory bulb abnormalities (22%), white matter abnormalities (20%), cerebral microbleeds (17%), grey matter abnormalities (12%), leptomeningeal enhancement (10%), ADEM (Acute Disseminated Encephalomyelitis) or ADEM-like lesions (10%), non-traumatic ICH (10%), cranial neuropathy (8%), cortical gray matter signal changes compatible with encephalitis (8%), basal ganglia abnormalities (5%), PRES (Posterior Reversible Encephalopathy Syndrome) (3%), hypoxic-ischemic lesions (4%), venous thrombosis (2%), and cytotoxic lesions of the corpus callosum (2%).
CONCLUSION
The present study revealed that a considerable proportion of patients with COVID-19 might harbor neurological abnormalities detectable by MRI. Among various findings, the most common MRI alterations are acute/subacute infarction, olfactory bulb abnormalities, white matter abnormalities, and cerebral microbleeds.
PubMed: 37535100
DOI: 10.1007/s00415-023-11914-9 -
Neuropsychology Review Mar 2024Olfactory training (OT), or smell training,consists of repeated exposure to odorants over time with the intended neuroplastic effect of improving or remediating... (Review)
Review
Olfactory training (OT), or smell training,consists of repeated exposure to odorants over time with the intended neuroplastic effect of improving or remediating olfactory functioning. Declines in olfaction parallel declines in cognition in various pathological conditions and aging. Research suggests a dynamic neural connection exists between olfaction and cognition. Thus, if OT can improve olfaction, could OT also improve cognition and support brain function? To answer this question, we conducted a systematic review of the literature to determine whether there is evidence that OT translates to improved cognition or altered brain morphology and connectivity that supports cognition. Across three databases (MEDLINE, Scopus, & Embase), 18 articles were identified in this systematic review. Overall, the reviewed studies provided emerging evidence that OT is associated with improved global cognition, and in particular, verbal fluency and verbal learning/memory. OT is also associated with increases in the volume/size of olfactory-related brain regions, including the olfactory bulb and hippocampus, and altered functional connectivity. Interestingly, these positive effects were not limited to patients with smell loss (i.e., hyposmia & anosmia) but normosmic (i.e., normal ability to smell) participants benefitted as well. Implications for practice and research are provided.
Topics: Humans; Brain; Cognition; Olfaction Disorders; Olfactory Training; Smell
PubMed: 36725781
DOI: 10.1007/s11065-022-09573-0 -
Molecular Neurobiology Oct 2022Neural regeneration has troubled investigators worldwide in the past decades. Currently, cell transplantation emerged as a breakthrough targeted therapy for spinal cord... (Review)
Review
Neural regeneration has troubled investigators worldwide in the past decades. Currently, cell transplantation emerged as a breakthrough targeted therapy for spinal cord injury (SCI) in the neurotrauma field, which provides a promising strategy in neural regeneration. Olfactory ensheathing cells (OECs), a specialized type of glial cells, is considered as the excellent candidate due to its unique variable and intrinsic regeneration-supportive properties. In fact, OECs could support olfactory receptor neuron turnover and axonal extension, which is essential to maintain the function of olfactory nervous system. Hitherto, an increasing number of literatures demonstrate that transplantation of OECs exerts vital roles in neural regeneration and functional recovery after neural injury, including central and peripheral nervous system. It is common knowledge that the deteriorating microenvironment (ischemia, hypoxia, scar, acute and chronic inflammation, etc.) resulting from injured nervous system is adverse for neural regeneration. Interestingly, recent studies indicated that OECs could promote neural repair through improvement of the disastrous microenvironments, especially to the overwhelmed inflammatory responses. Although OECs possess unusual advantages over other cells for neural repair, particularly in SCI, the mechanisms of OEC-mediated neural repair are still controversial with regard to anti-inflammation. Therefore, it is significant to summarize the anti-inflammation property of OECs, which is helpful to understand the biological characteristics of OECs and drive future studies. Here, we mainly focus on the anti-inflammatory role of OECs to make systematic review and discuss OEC-based therapy for CNS injury.
Topics: Anti-Inflammatory Agents; Cell Transplantation; Humans; Nerve Regeneration; Neuroglia; Olfactory Bulb; Spinal Cord; Spinal Cord Injuries
PubMed: 35962300
DOI: 10.1007/s12035-022-02983-4 -
Neuroradiology Jan 2023The neurotropism of SARS-CoV-2 and the consequential damage to the olfactory system have been proposed as one of the possible underlying causes of olfactory dysfunction... (Meta-Analysis)
Meta-Analysis
PURPOSE
The neurotropism of SARS-CoV-2 and the consequential damage to the olfactory system have been proposed as one of the possible underlying causes of olfactory dysfunction in COVID-19. We aimed to aggregate the results of the studies which reported imaging of the olfactory system of patients with COVID-19 versus controls.
METHODS
PubMed and EMBASE were searched to identify relevant literature reporting the structural imaging characteristics of the olfactory bulb (OB), olfactory cleft, olfactory sulcus (OS), or olfactory tract in COVID-19 patients. Hedge's g and weighted mean difference were used as a measure of effect size. Quality assessment, subgroup analyses, meta-regression, and sensitivity analysis were also conducted.
RESULTS
Ten studies were included in the qualitative synthesis, out of which seven studies with 183 cases with COVID-19 and 308 controls without COVID-19 were enrolled in the quantitative synthesis. No significant differences were detected in analyses of right OB volume and left OB volume. Likewise, right OS depth and left OS depth were also not significantly different in COVID-19 cases compared to non-COVID-19 controls. Also, we performed subgroup analysis, meta-regression, and sensitivity analysis to investigate the potential effect of confounding moderators.
CONCLUSION
The findings of this review did not confirm alterations in structural imaging of the olfactory system, including OB volume and OS depth by Covid-19 which is consistent with the results of recent histopathological evaluations.
Topics: Humans; Olfaction Disorders; COVID-19; SARS-CoV-2; Magnetic Resonance Imaging; Olfactory Bulb
PubMed: 35843987
DOI: 10.1007/s00234-022-03014-8 -
American Journal of Rhinology & Allergy Sep 2022Patients with acquired, idiopathic olfactory dysfunction (OD) commonly undergo magnetic resonance imaging (MRI) evaluation to rule out intracranial pathologies. This...
BACKGROUND
Patients with acquired, idiopathic olfactory dysfunction (OD) commonly undergo magnetic resonance imaging (MRI) evaluation to rule out intracranial pathologies. This practice is highly debated given the expense of MRI relative to the probability of detecting a treatable lesion. This, combined with the increasing use of MRI in research to investigate the mechanisms underlying OD, provided the impetus for this comprehensive review.
OBJECTIVE
The purpose of this systematic review was to both assess the utility of MRI in diagnosis of idiopathic OD and to describe MRI findings among mixed OD etiologies to better understand its role as a research tool in this patient population.
METHODS
A literature search of PubMed, Embase, Cochrane, Web of Science, and Scopus for studies with original MRI data for patients with OD was completed. Studies exclusively investigating patients with neurocognitive deficits or those studying traumatic or congenital etiologies of OD were excluded.
RESULTS
From 1758 candidate articles, 33 studies were included. Four studies reviewed patients with idiopathic OD for structural pathologies on MRI, of which 17 of 372 (4.6%) patients had a potential central cause identified, and 3 (0.8%) had an olfactory meningioma or olfactory neuroblastoma. Fourteen studies (42.4%) reported significant correlation between olfactory bulb volume and olfactory outcomes, and 6 studies (18.8%) reported gray matter volume reduction, specifically in the orbitofrontal cortex, anterior cingulate cortex, insular cortex, parahippocampal, and piriform cortex areas, in patients with mixed OD etiologies. Functional MRI studies reported reduced brain activation and functional connectivity in olfactory network areas.
CONCLUSION
MRI uncommonly detects intracranial pathology in patients with idiopathic OD. Among patients with mixed OD etiologies, reduced olfactory bulb and gray matter volume are the most common abnormal findings on MRI. Further research is required to better understand the role of MRI and its cost-effectiveness in patients with acquired, idiopathic OD.
Topics: Gray Matter; Humans; Magnetic Resonance Imaging; Olfaction Disorders; Olfactory Bulb; Olfactory Cortex; Smell
PubMed: 35585698
DOI: 10.1177/19458924221096913 -
The Laryngoscope Jun 2022Olfactory dysfunction (OD) is a common presenting symptom of COVID-19 infection. Radiological imaging of the olfactory structures in patients with COVID-19 and OD can... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVE
Olfactory dysfunction (OD) is a common presenting symptom of COVID-19 infection. Radiological imaging of the olfactory structures in patients with COVID-19 and OD can potentially shed light on its pathogenesis, and guide clinicians in prognostication and intervention.
METHODS
PubMed, Embase, Cochrane, SCOPUS were searched from inception to August 1, 2021. Three reviewers selected observational studies, case series, and case reports reporting radiological changes in the olfactory structures, detected on magnetic resonance imaging, computed tomography, or other imaging modalities, in patients aged ≥18 years with COVID-19 infection and OD, following preferred reporting items for systematic reviews and meta-analyses guidelines and a PROSPERO-registered protocol (CRD42021275211). We described the proportion of radiological outcomes, and used random-effects meta-analyses to pool the prevalence of olfactory cleft opacification, olfactory bulb signal abnormalities, and olfactory mucosa abnormalities in patients with and without COVID-19-associated OD.
RESULTS
We included 7 case-control studies (N = 353), 11 case series (N = 154), and 12 case reports (N = 12). The pooled prevalence of olfactory cleft opacification in patients with COVID-19 infection and OD (63%, 95% CI = 0.38-0.82) was significantly higher than that in controls (4%, 95% CI = 0.01-0.13). Conversely, similar proportions of cases and controls demonstrated olfactory bulb signal abnormalities (88% and 94%) and olfactory mucosa abnormalities (2% and 0%). Descriptive analysis found that 55.6% and 43.5% of patients with COVID-19 infection and OD had morphological abnormalities of the olfactory bulb and olfactory nerve, respectively, while 60.0% had abnormal olfactory bulb volumes.
CONCLUSION
Our findings implicate a conductive mechanism of OD, localized to the olfactory cleft, in approximately half of the affected COVID-19 patients. Laryngoscope, 132:1260-1274, 2022.
Topics: Adolescent; Adult; COVID-19; Humans; Olfaction Disorders; Olfactory Bulb; Olfactory Mucosa; Smell
PubMed: 35318656
DOI: 10.1002/lary.30078 -
Chinese Medical Sciences Journal =... Mar 2022Background Anosmia is one of the symptoms in individuals with SARS-CoV-2 infection. In anosmic patients, SARS-CoV-2 temporarily alters the signaling process in olfactory...
Background Anosmia is one of the symptoms in individuals with SARS-CoV-2 infection. In anosmic patients, SARS-CoV-2 temporarily alters the signaling process in olfactory nerve cells and olfactory bulb (OB), which eventually damages the structure of the olfactory epithelium, leading to a permanent disorder in the olfactory pathway that this damaged structure is showed in MRI imaging Methods Two investigators independently searched four databases consisting of PubMed, ProQuest, Scopus, and Web of Science for relevant records as of November 11, 2020 with no time, space, and language restrictions. Google Scholar was also searched for the related resources within the time limit of 2020. All the found articles were reviewed based on the PRISMA flow diagram. Qualitative studies, case reports, editorials, letters, and other non-original studies were excluded from this systematic analysis. Results Initial search yielded 434 records. After reviewing the titles and abstracts, we selected 74 articles; finally, 8 articles were depicted to be investigated and read in full text. The obtained results showed an increase in the width and volume of the olfactory cleft (OC), complete or partial destruction of OC, and complete occlusion of OC in COVID-19 patients. Deformation and degeneration as well as a subtle asymmetry were evident in the OBs. Computed tomography (CT), meganetic resonance imaging (MRI), and positron emission tomography (PET) were used to detect the outcomes of anosmia in these studies. Conclusions The changes in OC are greater than those in OB in patients with COVID-19, mainly due to the inflammatory and immune responses in OC. However, fewer changes in OB are due to neurological or vascular disorders. Topical steroid therapy and topical saline can be helpful.
PubMed: 35256044
DOI: 10.24920/003982