-
Journal of Clinical Neuromuscular... Dec 2023Isaac syndrome (IS) is a condition characterized by peripheral nerve hyperexcitability caused by voltage-gated potassium channel (VGKC)-complex antibodies. Muscle...
OBJECTIVES
Isaac syndrome (IS) is a condition characterized by peripheral nerve hyperexcitability caused by voltage-gated potassium channel (VGKC)-complex antibodies. Muscle twitching, stiffness, hypertrophy, and dysautonomic characteristics, such as hyperhidrosis, are common manifestations. The syndrome can be autoimmune or paraneoplastic, with thymoma being a common cause of paraneoplastic IS. Furthermore, this condition could be handed down from one generation to another. However, there is limited information regarding outcomes, relapses, associated syndromes, associated malignancies (other than thymoma), and treatment options. Despite its rarity, there remains a need for effective management strategies for patients with IS. To address this gap, we conducted a systematic review to summarize the most common and effective treatments of IS in immunomodulatory agents and symptomatic medications, as well as to describe outcomes, relapses, and associated malignancies. Altogether, this review serves to guide clinical practice recommendations for IS and highlight areas for further research.
METHODS
We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol to conduct a systematic review of cases reposted through the PubMed and Google Scholar databases. The terms "Isaac Syndrome" and "Acquired Neuromyotonia" were used. The Joanna Briggs Institute's critical appraisal tool was used to evaluate the quality of the included studies.
RESULTS
We identified 61 case reports and 4 case series, comprising a total of 70 patients with IS (mean age at onset: 42.5 ± 18 years, and 69% were males). Fourteen cases reported relapses. Thymoma was the most common malignancy associated with IS, followed by lymphoma. Among various serum antibodies, voltage-gated potassium channel-complex antibodies were the most reported antibodies elevated in IS (reported in 38 patients and elevated in 21 patients [55.2%]), followed by acetylcholine ganglionic receptor antibodies, which were reported in 30% of patients (n = 21) and were elevated in 5 cases. The most common electromyography findings were myokymic discharges (n = 22), followed by fasciculations (n = 21) and neuromyotonia (n = 19). For treatment, combining anticonvulsants such as carbamazepine with immunotherapy therapy showed the best results in controlling the symptoms. Among immunotherapy therapies, the combination of plasma exchange plus intravenous high-dose steroids achieved the best results in the acute treatment of IS ([n = 6], with improvement noted in 83.3% [n = 5] of cases). Among the symptomatic treatments with anticonvulsants, carbamazepine was the most efficacious anticonvulsant in treatment of IS, with an average effective dosing of 480 mg/day (carbamazepine was used in 32.3% of acute treatment strategies [n = 23], with improvement noted in 73.9% [n = 17] of cases).
CONCLUSIONS
IS a rare neuromuscular syndrome that tends to affect middle-aged men. These patients should be screened for thymoma and other malignancies such as lymphomas. The management of IS symptoms can be challenging, but based on our review, the combination of multiple immunosuppressives such as IV steroids and plasmapheresis with anticonvulsants such as carbamazepine seems to achieve the best results.
Topics: Male; Middle Aged; Humans; Female; Isaacs Syndrome; Thymoma; Anticonvulsants; Thymus Neoplasms; Autoantibodies; Potassium Channels, Voltage-Gated; Carbamazepine; Receptors, Cholinergic; Steroids; Recurrence
PubMed: 37962197
DOI: 10.1097/CND.0000000000000460 -
Frontiers in Physiology 2022Endocannabinoids (eCBS) are endogenously derived lipid signaling molecules that serve as tissue hormones and interact with multiple targets, mostly within the...
Endocannabinoids (eCBS) are endogenously derived lipid signaling molecules that serve as tissue hormones and interact with multiple targets, mostly within the endocannabinoid system (ECS). The ECS is a highly conserved regulatory system involved in homeostatic regulation, organ formation, and immunomodulation of chordates. The term "cannabinoid" evolved from the distinctive class of plant compounds found in , an ancient herb, due to their action on CB1 and CB2 receptors. CB1/2 receptors are the primary targets for eCBs, but their effects are not limited to the ECS. Due to the high interest and extensive research on the ECS, knowledge on its constituents and physiological role is substantial and still growing. Crosstalk and multiple targeting of molecules are common features of endogenous and plant compounds. Cannabimimetic molecules can be divided according to their origin, natural or synthetic, including phytocannabinoids (pCB's) or synthetic cannabinoids (sCB's). The endocannabinoid system (ECS) consists of receptors, transporters, enzymes, and signaling molecules. In this review, we focus on the effects of cannabinoids on Cys-loop receptors. Cys-loop receptors belong to the class of membrane-bound pentameric ligand gated ion channels, each family comprising multiple subunits. Mammalians possess GABA type A receptors (GABAAR), glycine receptors (GlyR), serotonin receptors type 3 (5-HT3R), and nicotinic acetylcholine receptors (nAChR). Several studies have shown different modulatory effects of CBs on multiple members of the Cys-loop receptor family. We highlight the existing knowledge, especially on subunits and protein domains with conserved binding sites for CBs and their possible pharmacological and physiological role in epilepsy and in chronic pain. We further discuss the potential for cannabinoids as first line treatments in epilepsy, chronic pain and other neuropsychiatric conditions, indicated by their polypharmacology and therapeutic profile.
PubMed: 36439263
DOI: 10.3389/fphys.2022.1044575 -
Frontiers in Cardiovascular Medicine 2023Coronary artery spasm (CAS), encompassing epicardial and microvascular spasm, is increasingly recognized as cause of angina in patients with non-obstructive coronary... (Review)
Review
BACKGROUND
Coronary artery spasm (CAS), encompassing epicardial and microvascular spasm, is increasingly recognized as cause of angina in patients with non-obstructive coronary artery disease (ANOCA). However, various spasm provocation testing protocols and diagnostic criteria are used, making diagnosis and characterization of these patients difficult and interpretation of study results cumbersome. This review provides a structured overview of the prevalence, characterization and prognosis of CAS worldwide in men and women.
METHODS
A systematic review identifying studies describing ANOCA patients with CAS was performed. Multiple outcomes (prevalence, clinical features, and prognosis) were assessed. Data, except for prognosis were pooled and analysed using random effects meta-analysis models.
RESULTS
Twenty-five publications ( = 14.554) were included (58.2 years; 44.2% women). Percentages of epicardial constriction to define epicardial spasm ranged from >50% to >90%. Epicardial spasm was prevalent in 43% (range 16-73%), with a higher prevalence in Asian vs. Western World population (52% vs. 33%, = 0.014). Microvascular spasm was prevalent in 25% (range 7-39%). Men were more likely to have epicardial spasm (61%), women were more likely to have microvascular spasm (64%). Recurrent angina is frequently reported during follow-up ranging from 10 to 53%.
CONCLUSION
CAS is highly prevalent in ANOCA patients, where men more often have epicardial spasm, women more often have microvascular spasm. A higher prevalence of epicardial spasm is demonstrated in the Asian population compared to the Western World. The prevalence of CAS is high, emphasizing the use of unambiguous study protocols and diagnostic criteria and highlights the importance of routine evaluation of CAS in men and women with ANOCA.
SYSTEMATIC REVIEW REGISTRATION
https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=272100.
PubMed: 36993994
DOI: 10.3389/fcvm.2023.1129159 -
International Journal of Molecular... Apr 2023The sleep-wake cycle is a complex multifactorial process involving several neurotransmitters, including acetylcholine, norepinephrine, serotonin, histamine, dopamine,... (Review)
Review
The sleep-wake cycle is a complex multifactorial process involving several neurotransmitters, including acetylcholine, norepinephrine, serotonin, histamine, dopamine, orexin and GABA, that can be, in turn, regulated by different nutrients involved in their metabolic pathways. Although good sleep quality in children has been proven to be a key factor for optimal cognitive, physical and psychological development, a significant and ever-increasing percentage of the pediatric population suffers from sleep disorders. In children, behavioral interventions along with supplements are recommended as the first line treatment. This systematic review was conducted, according to the PRISMA guidelines, with the purpose of assessing the principal nutrients involved in the pathways of sleep-regulating neurotransmitters in children and adolescents. Our focus was the utilization of over the counter (OTC) products, specifically iron, hydroxytryptophan, theanine and antihistamines in the management of different pediatric sleep disorders with the intention of providing a practical guide for the clinician.
Topics: Adolescent; Humans; Child; Sleep; Sleep Initiation and Maintenance Disorders; Histamine; Histamine Antagonists; Neurotransmitter Agents; Sleep Wake Disorders
PubMed: 37175525
DOI: 10.3390/ijms24097821 -
CNS Drugs Nov 2022For decades, treatment of mood disorders, psychoses, anxiety and dementia have been confounded by limited efficacy and high rates of treatment resistance. Preclinical... (Meta-Analysis)
Meta-Analysis
BACKGROUND
For decades, treatment of mood disorders, psychoses, anxiety and dementia have been confounded by limited efficacy and high rates of treatment resistance. Preclinical and clinical evidence have highlighted disruption of cholinergic signalling in several neuropsychiatric conditions and examined intervention strategies including acetylcholinesterase inhibitors and nicotinic receptor-targeted intervention. However, the effectiveness of these approaches is often curtailed by on-target side effects. Post mortem studies implicate muscarinic receptor dysregulation in neuropsychiatric pathophysiology; therefore, we conducted a systematic review and meta-analysis to investigate the therapeutic efficacy and safety of muscarinic receptor-targeted interventions in adults with neuropsychiatric disorders.
METHODS
PubMed, EMBASE, PsycINFO, EBSCO and Web of Science were searched using relevant keywords from database inception to 7 August 2022. Randomised, double-blind, placebo-controlled studies were included if they investigated the effect of muscarinic receptor-targeted intervention in adults with a diagnosis of a neuropsychiatric disorder and were published in English. A narrative synthesis approach was adopted to describe the findings. Wherever three or more studies with a similar intervention were available, effect sizes were calculated, and a meta-analysis was performed. Cochrane risk-of-bias-2 tool was utilised to assess the risk of bias, and sensitivity analyses were performed to identify publication bias. Certainty analysis (high, moderate, low and/or very low) was conducted using GRADE criteria.
RESULTS
Overall, 33 studies met the inclusion criteria and 5 were included in the meta-analysis. Despite a limited pool with several different interventions, we found therapeutic efficacy of xanomeline (M/M agonist) in primary psychotic disorders plus behavioural and psychological symptoms of dementia. Scopolamine showed a significant antidepressant effect in a combined cohort of major depressive and bipolar disorders in the short-term outcome measure, but no effect following cessation of treatment. Results from bias assessments suggest "very low" certainty in the antidepressant effect of scopolamine. Critical limitations of the current literature included low power, high heterogeneity in the patient population and a lack of active comparators.
CONCLUSION
While the results are not definitive, findings on muscarinic receptor-targeted interventions in several mental disorders are promising in terms of efficacy and safety, specifically in treating schizophrenia, mood disorders, and behavioural and psychiatric symptoms of Alzheimer's disease. However, orthosteric muscarinic receptor-targeted interventions are associated with a range of peripheral adverse effects that are thought to be mediated via M/M receptors. The orthosteric binding site of muscarinic acetylcholine receptors is remarkably conserved, posing a challenge for subtype-selective interventions; nonetheless allosteric ligands with biased signalling pathways are now in development. We conclude that adequately powered prospective studies with subtype-selective interventions are required to determine the clinical effectiveness of muscarinic-receptor targeted interventions for the treatment of neuropsychiatric disorders.
Topics: Adult; Humans; Depressive Disorder, Major; Prospective Studies; Acetylcholinesterase; Treatment Outcome; Antidepressive Agents; Receptors, Muscarinic; Scopolamine Derivatives; Dementia; Randomized Controlled Trials as Topic
PubMed: 36269510
DOI: 10.1007/s40263-022-00964-8 -
ANZ Journal of Surgery Sep 2023Chronic intestinal pseudo-obstruction (CIPO) may be a primary or secondary phenomenon and is often multifactorial. Treatment is largely directed at improving colonic... (Review)
Review
BACKGROUND
Chronic intestinal pseudo-obstruction (CIPO) may be a primary or secondary phenomenon and is often multifactorial. Treatment is largely directed at improving colonic motility. The use of cholinesterase inhibitors such as pyridostigmine has been hypothesized to increase acetylcholine in the bowel, improving symptoms and transit times.
METHODS
A systematic review of the use of pyridostigmine in CIPO was conducted using scientific and commercial search engines identifying scientific studies enrolling adult human subjects, published from 2000 to 2022 in the English language.
RESULTS
Four studies were identified including two randomized controlled trials (RCT) and two observational studies. The studies had heterogenous inclusion criteria, dosing regimens and reported outcomes. Two studies were identified as being at high risk of bias. All studies reported improved patient outcomes with use of pyridostigmine, and low rates (4.3%) of mild cholinergic side effects. No major side effects were reported.
CONCLUSION
The use of pyridostigmine in management of CIPO is biologically plausible due to its ability to increase colonic motility, and early studies on its role are uniformly suggestive of benefit with low side-effect profile. Four clinical studies have been conducted to date, with small sample sizes, heterogeneity and high risk of bias. Further high-quality studies are required to enable assessment of pyridostigmine's utility as an effective management strategy in CIPO.
Topics: Adult; Humans; Pyridostigmine Bromide; Gastrointestinal Motility; Intestinal Pseudo-Obstruction; Cholinesterase Inhibitors; Chronic Disease
PubMed: 37132128
DOI: 10.1111/ans.18478 -
Clinical Autonomic Research : Official... Dec 2017Primary hyperhidrosis is a pathological disorder of unknown etiology, affecting 0.6-5% of the population, and causing severe functional and social handicaps. As the... (Review)
Review
PURPOSE
Primary hyperhidrosis is a pathological disorder of unknown etiology, affecting 0.6-5% of the population, and causing severe functional and social handicaps. As the etiology is unknown, it is not possible to treat the root cause. Recently some differences between affected and non-affected people have been reported. The aim of this review is to summarize these new etiological data.
METHODS
Search of the literature was performed in the PubMed/Medline Database and pertinent articles were retrieved and reviewed. Additional publications were obtained from the references of these articles.
RESULTS
Some anatomical and pathophysiological characteristics (as well as enzymatic, metabolic, and neurological dysfunctions) have been observed in hyperhidrotic subjects; three main possible etiological factors predominate. A familial trait seems to exist, and genetic loci associated with hyperhidrosis have been identified. Histological differences were observed in sympathetic ganglia of hyperhidrotic subjects: the ganglia were larger and contained a higher number of ganglion cells. A higher expression of acetylcholine and alpha-7 neuronal nicotinic receptor subunit in the sympathetic ganglia of patients with hyperhidrosis has been reported.
CONCLUSIONS
Despite these accumulated data, the etiology of primary hyperhidrosis remains obscure. Nevertheless, three main lines for future research seem to be delineated: genetics, histological observations, and enzymatic studies.
Topics: Animals; Ganglia, Sympathetic; Humans; Hyperhidrosis; Sympathectomy
PubMed: 28823102
DOI: 10.1007/s10286-017-0456-0 -
Age and Ageing Sep 2023Anticholinergic medications block the neurotransmitter acetylcholine in the brain and peripheral nervous system. Many medications have anticholinergic properties, and... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Anticholinergic medications block the neurotransmitter acetylcholine in the brain and peripheral nervous system. Many medications have anticholinergic properties, and the cumulative effect of these medications is termed anticholinergic burden. Increased anticholinergic burden can have short-term side effects such as dry mouth, blurred vision and urinary retention as well as long-term effects including dementia, worsening physical function and falls.
METHODS
We carried out a systematic review (SR) with meta-analysis (MA) looking at randomised controlled trials addressing interventions to reduce anticholinergic burden in older adults.
RESULTS
We identified seven papers suitable for inclusion in our SR and MA. Interventions included multi-disciplinary involvement in medication reviews and deprescribing of AC medications. Pooled data revealed no significant difference in outcomes between control and intervention group for falls (OR = 0.76, 95% CI: 0.52-1.11, n = 647), cognition (mean difference = 1.54, 95% CI: -0.04 to 3.13, n = 405), anticholinergic burden (mean difference = 0.04, 95% CI: -0.11 to 0.18, n = 710) or quality of life (mean difference = 0.04, 95% CI: -0.04 to 0.12, n = 461).
DISCUSSION
Overall, there was no significant difference with interventions to reduce anticholinergic burden. As we did not see a significant change in anticholinergic burden scores following interventions, it is likely other outcomes would not change. Short follow-up time and lack of training and support surrounding successful deprescribing may have contributed.
Topics: Humans; Aged; Quality of Life; Cholinergic Antagonists; Acetylcholine; Brain; Cognition
PubMed: 37740900
DOI: 10.1093/ageing/afad176 -
Neurology Oct 2023Ocular myasthenia gravis (OMG) is an autoimmune disorder resulting in ocular symptoms such as diplopia and ptosis. The proportion of patients who convert to secondary... (Meta-Analysis)
Meta-Analysis
BACKGROUND AND OBJECTIVES
Ocular myasthenia gravis (OMG) is an autoimmune disorder resulting in ocular symptoms such as diplopia and ptosis. The proportion of patients who convert to secondary generalized myasthenia gravis (SGMG) reported in the literature has been varied. The aim of this systematic review was to determine the clinical characteristics of patients with OMG and the proportion of SGMG conversion.
METHODS
We conducted an electronic database search for randomized controlled trials, prospective nonrandomized studies, observational studies, and retrospective studies in EMBASE, CENTRAL, MEDLINE, and Web of Science. We included studies with patients with OMG who initially presented with ocular symptoms and signs only and were seen in clinical practice, reporting on the characteristics and outcomes of SGMG. We excluded studies with pediatric and congenital myasthenia gravis populations. Eligible studies included articles written in any language and containing data on patients with OMG. The main outcome measured was the proportion of patients with OMG who converted to SGMG and risk factors associated with secondary generalization of OMG. Two independent reviewers screened titles and abstracts and extracted data from full texts, reporting findings according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The methodology was evaluated using the Joanna Briggs Institute critical appraisal forms. PROSPERO registration number: CRD2021285257.
RESULTS
Thirty-one studies were included in the quantitative and qualitative analysis. The proportion of generalization ranged from 11% to 84%. The pooled proportion was 39% (95% CI 32%-47%, = 95.86%, < 0.001 unweighted, low certainty). The pooled risk ratio of female sex for conversion to SGMG was 1.06 (95% CI 0.96-1.17, = 0% = 0.614, 21 studies included, very low certainty), and the pooled risk ratio of acetylcholine receptor (AChR) positivity was 1.30 (95% CI 1.05-1.56, = 0% = 0.455, 16 studies included, very low certainty).
DISCUSSION
Risk factors such as female sex and anti-AChR positivity have been identified to have possible associations with SGMG, but there are not enough quality observational studies. There is a need for a prospective global database of patients with OMG, including all countries with different populations.
Topics: Humans; Female; Child; Retrospective Studies; Myasthenia Gravis; Receptors, Cholinergic; Risk Factors; Blepharoptosis
PubMed: 37643888
DOI: 10.1212/WNL.0000000000207642 -
Journal of Neurophysiology Aug 2023Spinal motoneurons contain many ion channels and receptors upon which various cannabinoids are known to act. This scoping review involved the synthesis of evidence from... (Review)
Review
Spinal motoneurons contain many ion channels and receptors upon which various cannabinoids are known to act. This scoping review involved the synthesis of evidence from literature published before August 2022 about the effects of cannabinoids on quantifiable measures of motoneuron output. Four databases (MEDLINE, Embase, PsycINFO, and Web of Science CoreCollection) were queried and 4,237 unique articles were retrieved. Twenty-three studies met the inclusion criteria, and the findings from these studies were grouped according to four emergent themes: rhythmic motoneuron output, afferent feedback integration, membrane excitability, and neuromuscular junction transmission. This synthesis of evidence suggests that CB1 agonists can increase the frequency of cyclical patterns of motoneuron output (i.e., fictive locomotion). Furthermore, a majority of the evidence indicates that activating CB1 receptors at motoneuron synapses promotes excitation of motoneurons by enhancing excitatory synaptic transmission and depressing inhibitory synaptic transmission. The collated study results reveal variable effects of cannabinoids on acetylcholine release at the neuromuscular junction, and the influence of cannabinoids in this area requires more work to ensure precision of findings for CB1 agonist and antagonist impact. Altogether, these reports indicate that the endocannabinoid system is integral within the final common pathway and can impact motor output. This review contributes to understanding the effects of endocannabinoids on synaptic integration at the motoneuron and modulation of motor output.
Topics: Cannabinoids; Motor Neurons; Synapses; Synaptic Transmission; Neuromuscular Junction
PubMed: 37283484
DOI: 10.1152/jn.00460.2022