Advances in the Understanding and Management of Chronic Pain in Multiple Sclerosis: a Comprehensive Review

Perceived Social Isolation Among Patients With Multiple Sclerosis Suffering From Disease-Induced Pain and Disability

BACKGROUND

Patients with multiple sclerosis (MS) face a wide range of symptoms, including physical disability, imbalance, motor disorders, and acute and chronic pain. The psychosocial consequences of these symptoms may limit social well-being and quality of life in these patients.

PURPOSE

The aim of the study was to assess self-perceived social isolation among patients with MS and its relationship with pain intensity and disability status.

METHODS

This cross-sectional study was conducted on 200 patients with MS referred to neurology wards and clinics, the MS Association, and rehabilitation centers. Data collection tools used included a demographic information form, Numeric Pain Rating Scale, Expanded Disability Status Scale, and Social Isolation Questionnaire.

RESULTS

The mean scores of 4.66 ( SD = 1.15) for disability and 4.18 ( SD = 2.22) for pain intensity both indicated moderate levels of both. Of the sample, 21.5% (43 patients) reported no pain, 22.5% ( n = 45) reported mild pain, 35% ( n = 70) reported moderate pain, and 21% ( n = 42) reported intense pain. The average social isolation score was 63.52 ( SD = 3.32), which is higher than the theoretical average. Of the sample, 44.5% reported low social isolation, whereas 55.5% indicated high social isolation. Gender, duration of MS, economic status, disability status, and pain intensity were all found to be significantly associated with social isolation in patients with MS (all p s < .05).

CONCLUSIONS

Based on the findings, comprehensive support plans are necessary to improve psychosocial well-being, social life, and quality of life in patients with MS.

Efficacy of cannabinoids compared to the current standard treatments on symptom relief in persons with multiple sclerosis (CANSEP trial): study protocol for a randomized clinical trial

Background

Multiple sclerosis (MS) is an inflammatory and degenerative disease of the central nervous system. More than 90,000 Canadians are affected; a cure is yet to be found. Available treatments to manage the disease course are only partially effective. For many years, persons with MS (PwMS) have used cannabis to relax, to reduce pain and spasticity, or to improve sleep and daily functioning, despite the lack of scientific evidence on the efficacy of specific cannabinoids [i.e., tetrahydrocannabinol (THC) and cannabidiol (CBD)] on these MS symptoms. The purpose of this clinical trial is to assess the effectiveness of different doses of these cannabinoids, alone or combined, on spasticity relief, compared to placebo. Moreover, we aim to determine which treatment is best effective to address other key MS conditions.

Methods

A double-blinded, randomized, factorial, placebo-controlled trial will be performed. We intend to include up to 250 PwMS aged over 21 recruited from the Centre hospitalier de l'Université de Montréal MS Clinic. PwMS will be randomly assigned on a 1:1:1:1 ratio to one of the trial arms: THC alone, CBD alone, THC/CBD combination, or placebo, using stratified blocked randomization, with random blocks within each stratum. The primary outcome is a self-assessment of spasticity using the mean Numeric Rating Scale score over 7 days. The main outcome will be the difference in this score at 4 weeks compared to baseline. Secondary outcomes include assessments of spasticity as measured by a clinician, pain, fatigue, sleep, bowel, bladder, and sexual dysfunction, restless legs syndrome, mental health, quality of life, mobility, cognitive functioning, and adverse events. Treatment responders are eligible for a 12-week extension phase, using the same treatment allocation and assessments.

Discussion

Previous clinical studies examined the efficacy of cannabis-based medicines in PwMS, mostly using products with 1:1 THC/CBD ratio. The major barrier to effectively use cannabis in real-world clinical settings is the lack of evidence on benefits of specific cannabinoids and information on possible related risks. The CANSEP study will contribute to overcome these limitations and identify the risks and benefits of cannabis-based treatments in PwMS.

Clinical trial registration

ClinicalTrials.Gov, NCT05092191.

Multiple Sclerosis: An Emergency Medicine-Focused Narrative Review

BACKGROUND

Multiple sclerosis (MS) is a rare but serious condition associated with significant morbidity.

OBJECTIVE

This review provides a focused assessment of MS for emergency clinicians, including the presentation, evaluation, and emergency department (ED) management based on current evidence.

DISCUSSION

MS is an autoimmune disorder targeting the central nervous system (CNS), characterized by clinical relapses and radiological lesions disseminated in time and location. Patients with MS most commonly present with long tract signs (e.g., myelopathy, asymmetric spastic paraplegia, urinary dysfunction, Lhermitte's sign), optic neuritis, or brainstem syndromes (bilateral internuclear ophthalmoplegia). Cortical syndromes or multifocal presentations are less common. Radiologically isolated syndrome and clinically isolated syndrome (CIS) may or may not progress to chronic forms of MS, including relapsing remitting MS, primary progressive MS, and secondary progressive MS. The foundation of outpatient management involves disease-modifying therapy, which is typically initiated with the first signs of disease onset. Management of CIS and acute flares of MS in the ED includes corticosteroid therapy, ideally after diagnostic testing with imaging and lumbar puncture for cerebrospinal fluid analysis. Emergency clinicians should evaluate whether patients with MS are presenting with new-onset debilitating neurological symptoms to avoid unnecessary testing and admissions, but failure to appropriately diagnose CIS or MS flare is associated with increased morbidity.

CONCLUSIONS

An understanding of MS can assist emergency clinicians in better diagnosing and managing this neurologically devastating disease.

Dysregulation of sphingolipid metabolism in pain

Pain is a clinical condition that is currently of great concern and is often caused by tissue or nerve damage or occurs as a concomitant symptom of a variety of diseases such as cancer. Severe pain seriously affects the functional status of the body. However, existing pain management programs are not fully satisfactory. Therefore, there is a need to delve deeper into the pathological mechanisms underlying pain generation and to find new targets for drug therapy. Sphingolipids (SLs), as a major component of the bilayer structure of eukaryotic cell membranes, also have powerful signal transduction functions. Sphingolipids are abundant, and their intracellular metabolism constitutes a huge network. Sphingolipids and their various metabolites play significant roles in cell proliferation, differentiation, apoptosis, etc., and have powerful biological activities. The molecules related to sphingolipid metabolism, mainly the core molecule ceramide and the downstream metabolism molecule sphingosine-1-phosphate (S1P), are involved in the specific mechanisms of neurological disorders as well as the onset and progression of various types of pain, and are closely related to a variety of pain-related diseases. Therefore, sphingolipid metabolism can be the focus of research on pain regulation and provide new drug targets and ideas for pain.

Pharmacological and Non-pharmacological Approaches for the Management of Neuropathic Pain in Multiple Sclerosis

Multiple sclerosis is a chronic inflammatory disease that affects the central nervous system and can cause various types of pain including ongoing extremity pain, Lhermitte's phenomenon, trigeminal neuralgia, and mixed pain. Neuropathic pain is a major concern for individuals with multiple sclerosis as it is directly linked to myelin damage in the central nervous system and the management of neuropathic pain in multiple sclerosis is challenging as the options available have limited efficacy and can cause unpleasant side effects. The literature search was conducted across two databases, PubMed, and Google Scholar. Eligible studies included clinical trials, observational studies, meta-analyses, systematic reviews, and narrative reviews. The objective of this article is to provide an overview of literature on pharmacological and non-pharmacological strategies employed in the management of neuropathic pain in multiple sclerosis. Pharmacological options include cannabinoids, muscle relaxants (tizanidine, baclofen, dantrolene), anticonvulsants (benzodiazepines, gabapentin, phenytoin, carbamazepine, lamotrigine), antidepressants (duloxetine, venlafaxine, tricyclic antidepressants), opioids (naltrexone), and botulinum toxin variants, which have evidence from various clinical trials. Non-pharmacological approaches for trigeminal neuralgia may include neurosurgical methods. Non-invasive methods, physical therapy, and psychotherapy (cognitive behavioral therapy, acceptance and commitment therapy and mindfulness-based stress reduction) may be recommended for patients with neuropathic pain in multiple sclerosis. The choice of treatment depends on the severity and type of pain as well as other factors, such as patient preferences and comorbidities. There is a pressing need for healthcare professionals and researchers to prioritize the development of better strategies for managing multiple sclerosis-induced neuropathic pain.

Interim guidelines for the assessment and treatment of pain in children with multiple sclerosis

Introduction

Pain in multiple sclerosis (MS) is common, but literature on pain in children with MS remains scarce. Pain has physical, psychological, and social implications in MS, and both comprehensive assessment and interdisciplinary management approaches are needed. We sought to develop an interdisciplinary interim guideline for the assessment and management of pain in children with MS.

Methods and materials

We convened a modified Delphi panel composed of 13 experts in pediatric and adult MS neurology, physiotherapy, pain, patient lived-experience, advanced practice nursing, psychology, physiatry, and MS research. A survey was sent to panelists for anonymous completion. The panel discussed survey themes extracted by the panel chair. The process was repeated twice.

Results

Thirteen assessment and treatment recommendations were produced regarding pain in children with MS.

Discussion

Future studies will assess implementation of these pain assessment and treatment guidelines in the clinical setting.

Rest-Activity Rhythm, Pain, and Motor Activity in Multiple Sclerosis

BACKGROUND

Although the relationships among physical disability, mood disorders, and pain are well described in multiple sclerosis (MS), little is known about whether those symptoms are associated with sleep disturbances.

METHODS

Forty-six patients with MS experiencing pain participated. Sleep was indirectly measured by assessing rest-activity rhythm via actigraphy: interdaily stability, intradaily variability, and relative amplitude. Pain was assessed using visual and verbal analog scales, mood by the Beck Depression Inventory and Symptom Checklist-90, and physical disability by the Expanded Disability Status Scale.

RESULTS

Incorporating mood, pain, and physical disability into 1 regression model resulted in a significant association with interdaily stability.

CONCLUSIONS

Compared with intradaily variability and relative amplitude, interdaily stability seems to be the most vulnerable actigraphy variable for mood disturbances, pain, and physical disabilities.

Characterizing cannabis use in a sample of adults with multiple sclerosis and chronic pain: An observational study

BACKGROUND

Although cannabis has become an increasingly common method for pain management among people with multiple sclerosis (PwMS), there is a dearth of knowledge regarding the types of cannabis products used as well as the characteristics of cannabis users. The current study aimed to (1) describe the prevalence of cannabis use and the routes of administration of cannabis products in adults with an existing chronic pain condition and MS, (2) to examine differences in demographic and disease-related variables between cannabis users and non-users, and (3) to examine differences between cannabis users and non-users in pain-related variables, including pain intensity, pain interference, neuropathic pain, pain medication use, and pain-related coping.

METHODS

Secondary analysis of baseline data from participants with multiple sclerosis (MS) and chronic pain (N = 242) enrolled in an RCT comparing mindfulness-based cognitive therapy (MBCT), cognitive-behavioral therapy (CBT), and usual care for chronic pain. Statistical methods included t-tests, Mann-Whitney tests, chi-square tests, and Fisher's exact tests to assess for differences in demographic, disease-related, and pain-related variables between cannabis users and non-users.

RESULTS

Of the 242 participants included in the sample, 65 (27%) reported the use of cannabis for pain management. The most common route of administration was oil/tincture (reported by 42% of cannabis users), followed by vaped (22%) and edible (17%) products. Cannabis users were slightly younger than non-users (Medage 51.0 vs 55.0, p = .019) and reported higher median pain intensity scores (6.0 vs 5.0, p = .022), higher median pain interference scores (5.9 vs 5.4, p = .027), and higher median levels of neuropathic pain (20.0 vs 16.0, p = .001).

CONCLUSIONS

The current study identified factors that may intersect with cannabis use for pain management and adds to our current knowledge of the types of cannabis products used by PwMS. Future research should continue to investigate trends in cannabis use for pain management, especially as the legality and availability of products continue to shift. Additionally, longitudinal studies are needed to examine the effects of cannabis use on pain-related outcomes over time.

The emerging science of Glioception: Contribution of glia in sensing, transduction, circuit integration of interoception

Interoception is the process by which the nervous system regulates internal functions to achieve homeostasis. The role of neurons in interoception has received considerable recent attention, but glial cells also contribute. Glial cells can sense and transduce signals including osmotic, chemical, and mechanical status of extracellular milieu. Their ability to dynamically communicate "listening" and "talking" to neurons is necessary to monitor and regulate homeostasis and information integration in the nervous system. This review introduces the concept of "Glioception" and focuses on the process by which glial cells sense, interpret and integrate information about the inner state of the organism. Glial cells are ideally positioned to act as sensors and integrators of diverse interoceptive signals and can trigger regulatory responses via modulation of the activity of neuronal networks, both in physiological and pathological conditions. We believe that understanding and manipulating glioceptive processes and underlying molecular mechanisms provide a key path to develop new therapies for the prevention and alleviation of devastating interoceptive dysfunctions, among which pain is emphasized here with more focused details.

Pain and cognitive performance in adults with multiple sclerosis: A systematic review

INTRODUCTION

Pain and cognitive dysfunction are separately known to be important manifestations of multiple sclerosis (MS). Although pain is a complex subjective phenomenon with affective and cognitive aspects, it is not known if people with MS reporting pain are at greater risk of reduced performance in objective tests of cognition. The presence or direction of any association remains to be clarified, as do the roles of confounders such as fatigue, medication and mood.

METHODS

We conducted a systematic review of studies examining the relationship between pain and objectively measured cognition in adults with confirmed MS, according to a pre-registered protocol (PROSPERO 42,020,171,469). We carried out searches in MEDLINE, Embase and PsychInfo. Studies of adults with any subtype of MS, with chronic pain and in which cognitive evaluation was conducted by validated instruments were included. We evaluated the role of potential confounders (medication, depression, anxiety, fatigue and sleep) and described findings by eight pre-specified cognitive domains. Risk of bias was assessed using the Newcastle-Ottawa Scale.

RESULTS

11 studies (n = 3714 participants, range 16 to 1890 per study) were included in the review. Four studies included longitudinal data. Nine studies identified a relationship between pain and objectively measured cognitive performance. In seven of these studies, higher pain scores were associated with poorer cognitive performance. However, no evidence was available for some cognitive domains. Heterogeneous study methodology precluded meta-analysis. Studies infrequently controlled for the specified confounders. Most studies were judged to be at risk of bias.

DISCUSSION

Several studies, but not all, identified a negative relationship between pain severity and objectively measured cognitive performance. Our ability to further characterise this relationship is limited by study design and lack of evidence in many cognitive domains. Future studies should better establish this relationship and delineate the neurological substrate underpinning it.

Neuropathic pain, cognitive fusion, and alexithymia in patients with multiple sclerosis: Cross-sectional evidence for an explanatory model of anxiety symptoms

Multiple sclerosis (MS) presents a high prevalence, a marked increase worldwide, and a relevant impact on patients, public health, and society. Anxiety often cooccurs with MS and can contribute to the worsening of MS symptoms. However, knowledge about predictors of anxiety in Patients with MS (PwMS) is scarce.

OBJECTIVE

This preliminary study explored a novel model for anxiety symptoms in PwMS, including neuropathic pain (NeP), cognitive fusion (CF), experiential avoidance (EA), and alexithymia as explanatory factors.

METHOD

This cross-sectional study integrated two independent convenience samples: 107 PwMS recruited from the Portuguese Society for Multiple Sclerosis and 97 age- and gender-matched participants without the MS diagnosis (no-MS sample) recruited from the Portuguese general population. Self-report questionnaires that measured the constructs included in the model were administered to both groups.

RESULTS

PwMS showed significantly higher values regarding anxiety symptoms and their explanatory variables (NeP, CF, EA, alexithymia) in comparison to non-MS participants. In the MS sample, no correlations were found between anxiety symptoms and sociodemographic and clinical characteristics. NeP, CF, and alexithymia showed significant correlations with anxiety symptoms and significantly explained this symptomatology in simple linear regression models. Thus, these variables were retained in the multiple linear regression model and emerged as significant regressors that together explained 38% of the variance in anxious symptomatology in PwMS.

CONCLUSIONS

This preliminary study provides novel evidence on NeP and some maladaptive emotion regulation strategies related to EA/psychological inflexibility, as vulnerability to anxiety in PwMS can be considerably increased by CF and alexithymia. Clinical implications were discussed.

Inflammation in pathogenesis of chronic pain: Foe and friend

Chronic pain is a refractory health disease worldwide causing an enormous economic burden on individuals and society. Accumulating evidence suggests that inflammation in the peripheral nervous system (PNS) and central nervous system (CNS) is the major factor in the pathogenesis of chronic pain. The inflammation in the early- and late phase may have distinctive effects on the initiation and resolution of pain, which can be viewed as friend or foe. On the one hand, painful injuries lead to the activation of glial cells and immune cells in the PNS, releasing pro-inflammatory mediators, which contribute to the sensitization of nociceptors, leading to chronic pain; neuroinflammation in the CNS drives central sensitization and promotes the development of chronic pain. On the other hand, macrophages and glial cells of PNS and CNS promote pain resolution via anti-inflammatory mediators and specialized pro-resolving mediators (SPMs). In this review, we provide an overview of the current understanding of inflammation in the deterioration and resolution of pain. Further, we summarize a number of novel strategies that can be used to prevent and treat chronic pain by controlling inflammation. This comprehensive view of the relationship between inflammation and chronic pain and its specific mechanism will provide novel targets for the treatment of chronic pain.

The Effects of Relaxation Techniques on Pain, Fatigue, and Kinesiophobia in Multiple Sclerosis Patients: A 3-Arm Randomized Trial

ABSTRACT

BACKGROUND: In addition to the available medical treatment options, multiple sclerosis (MS) patients may tend toward complementary and integrative therapies. Relaxation techniques are a nonpharmacological and side-effect-free therapy option currently available to alleviate the symptoms of many different chronic diseases. The aim of this study was to examine and compare the effects of relaxation techniques on the pain, fatigue, and kinesiophobia in MS patients. METHODS: This 3-arm randomized controlled trial consisted of 80 MS patients. Relaxation techniques, progressive muscle relaxation and Benson relaxation technique were applied to 2 intervention groups, the third was the control group. The study lasted 12 weeks, and the patient information form, visual analog scale, Fatigue Severity Scale, and Tampa Scale for Kinesiophobia were used for data collection. RESULTS: There was a statistically significant decrease in pain, fatigue, and kinesiophobia levels in the intervention groups compared with the control group (P < .05). Progressive muscle relaxation was more effective than Benson relaxation technique (P < .05). CONCLUSION: Relaxation techniques are recommended for the management of symptoms of pain, fatigue, and kinesiophobia, which can often cause disability in MS patients, because they have no side effects and are practical administrations. These exercises are also promising in the rehabilitation process of MS patients.

Neuropathic Pain in Neurologic Disorders: A Narrative Review

Neuropathic pain is defined as a painful condition caused by neurological lesions or diseases. Sometimes, neurological disorders may also be associated with neuropathic pain, which can be challenging to manage. For example, multiple sclerosis (MS) may cause chronic centralized painful symptoms due to nerve damage. Other chronic neuropathic pain syndromes may occur in the form of post-stroke pain, spinal cord injury pain, and other central pain syndromes. Chronic neuropathic pain is associated with dysfunction, disability, depression, disturbed sleep, and reduced quality of life. Early diagnosis may help improve outcomes, and pain control can be an important factor in restoring function. There are more than 100 different types of peripheral neuropathy and those involving sensory neurons can provoke painful symptoms. Accurate diagnosis of peripheral neuropathy is essential for pain control. Further examples are represented by gluten neuropathy, which is an extraintestinal manifestation of gluten sensitivity and presents as a form of peripheral neuropathy; in these unusual cases, neuropathy may be managed with diet. Neuropathic pain has been linked to CoronaVirus Disease (COVID) infection both during acute infection and as a post-viral syndrome known as long COVID. In this last case, neuropathic pain relates to the host’s response to the virus. However, neuropathic pain may occur after any critical illness and has been observed as part of a syndrome following intensive care unit hospitalization.

Evidence Mapping Based on Systematic Reviews of Repetitive Transcranial Magnetic Stimulation on the Motor Cortex for Neuropathic Pain

BACKGROUND AND OBJECTIVE

There is vast published literature proposing repetitive transcranial magnetic stimulation (rTMS) technology on the motor cortex (M1) for the treatment of neuropathic pain (NP). Systematic reviews (SRs) focus on a specific problem and do not provide a comprehensive overview of a research area. This study aimed to summarize and analyze the evidence of rTMS on the M1 for NP treatment through a new synthesis method called evidence mapping.

METHODS

Searches were conducted in PubMed, EMBASE, Epistemonikos, and The Cochrane Library to identify the studies that summarized the effectiveness of rTMS for NP. The study type was restricted to SRs with or without meta-analysis. All literature published before January 23, 2021, was included. Two reviewers independently screened the literature, assessed the methodological quality, and extracted the data. The methodological quality of the included SRs was assessed by using the A Measurement Tool to Assess Systematic Reviews (AMSTAR-2). Data were extracted following a defined population, intervention, comparison, and outcome (PICO) framework from primary studies that included SRs. The same PICO was categorized into PICOs according to interventions [frequency, number of sessions (short: 1-5 sessions, medium: 5-10 sessions, and long: >10 sessions)] and compared. The evidence map was presented in tables and a bubble plot.

RESULTS

A total of 38 SRs met the eligibility criteria. After duplicate primary studies were removed, these reviews included 70 primary studies that met the scope of evidence mapping. According to the AMSTAR-2 assessment, the quality of the included SRs was critically low. Of these studies, 34 SRs scored "critically low" in terms of methodological quality, 2 SR scored "low," 1 SR scored "moderate," and 1 SR scored "high."

CONCLUSION

Evidence mapping is a useful methodology to provide a comprehensive and reliable overview of studies on rTMS for NP. Evidence mapping also shows that further investigations are necessary to highlight the optimal stimulation protocols and standardize all parameters to fill the evidence gaps of rTMS. Given that the methodological quality of most included SRs was "critically low," further investigations are advised to improve the methodological quality and the reporting process of SRs.

Pain Prevalence in Multiple Sclerosis in a Lisbon Tertiary Hospital: A Cross-Sectional Study

Background: Multiple sclerosis is a chronic neurological disease with increasing incidence and prevalence worldwide being the main cause of non-traumatic disability in young adults. Both acute and chronic pain have been mentioned as the most common symptoms among those patients.

Objective: This study was designed to evaluate the pain experience among patients with multiple sclerosis by describing its prevalence, characteristics, analgesic treatment and its efficacy, and also the impact of pain on quality of life.

Methods: A cross-sectional observation survey was carried out on patients with multiple sclerosis followed in a tertiary hospital. Data were collected between December 2019 and March 2021 from a structured telephone inquiry, applying two questionnaires, the Brief Pain Inventory and the McGill Pain Questionnaire (MPQ), to evaluate the prevalence of pain and its impact on quality of life (QoL). Clinical records were also consulted to obtain data on disease duration, year of diagnosis, MS type, Expanded Disability Status Scale (EDSS) score.

Results: Our sample included 305 patients in a universe of 1500, mainly women, with mean age of 44.27 years, and most of them presented with an outbreak-remission subtype of disease. One hundred twenty-four patients experienced pain which corresponds to 41% of the patients. Considering the patients who experienced pain, 67.7% were under treatment and of these, 64.3% with only one painkiller. Pain significantly interfered with general activity, mood, and regular work.

Conclusion: Pain was an important symptom in this group of patients with MS and significantly interfered with mood, general activity, and regular work. The maximum intensity of pain felt by patients was significant and only 67.7% of patients were under analgesic treatment with mean pain relief of 54. NSAIDs were the most used drugs followed by gabapentinoids and acetaminophen for the management of pain. Medical community must continue to study this population in order to improve the approach to pain in these patients and improve quality of life.

A Survey of Cannabis Use in a Large US-Based Cohort of People with Multiple Sclerosis

Background

As cannabis products become increasingly accessible across the United States, it is important to understand the contemporary use of cannabis for managing multiple sclerosis (MS) symptoms.

Methods

We invited participants with MS from the North American Research Committee on Multiple Sclerosis (NARCOMS) Registry (aged 18 years or older) to complete a supplemental survey on cannabis use between March and April 2020. Participants reported cannabis use, treated symptoms, patterns, preferences, methods of use, and the factors limiting use. Findings are reported using descriptive statistics.

Results

Of the 6934 participants invited, 3249 responded. Of the respondents, 31% reported having ever used cannabis to treat MS symptoms, with 20% currently using cannabis. The remaining 69% had never used cannabis for MS symptoms, for reasons including not enough data about efficacy (40%) and safety (27%), and concerns about legality (25%) and cost (18%). The most common symptoms current users were attempting to treat were spasticity (80%), pain (69%), and sleep problems (61%). Ever users (vs never users) were more likely to be younger, be non-White, have lower education, reside in the Northeast and West, be unemployed, be younger at symptom onset, be currently smoking, and have higher levels of disability and MS-related symptoms (all P < .001).

Conclusions

Despite concerns about insufficient safety and efficacy data, legality, and cost, almost one-third of NARCOMS Registry respondents report having tried nonprescription cannabis products in an attempt to alleviate their symptoms. Given the lack of efficacy and safety data on such products, future research in this area is warranted.

Shiatsu-associated physical therapy on pain and fatigue on people with multiple sclerosis

Abstract Introduction: Pain and fatigue are common symptoms in multiple sclerosis (MS). Shiatsu, a technique that uses the pressure of fingers, associated with manual therapy, exercises and stretching can be used to control these symptoms. Objective: To evaluate the effect of Shiatsu associated with physical therapy on pain and fatigue on people with MS. Methods: Randomized clinical trial with people diagnosed with MS divided into two groups: intervention group (IG) - Shiatsu-associated physical therapy (n = 9), and control group (CG, n = 8). Participants were assessed before and after treatment by the Expanded Disability Status Scale (EDSS), Neuropathic Pain Questionnaire (DN4), Visual Analog Scale (VAS) and Fatigue Impact Scale (MFIS), and description of sociodemographic. Results: Seventeen people with MS (9 men) aged 45.18 ± 3.06 years participated in this study. In the total sample, the average of DN4 was 1.65 ± 20.02, VAS was 2.29 ± 2.80, MFIS was 39.47 ± 29.67, and 52.9 % had a score > 38 in the MFIS that corresponds to presence of fatigue. The values pre/post-intervention/grade of p, respectively in the IG were DN4: 2.78 ± 2.16/2.0 ± 2.12/0.432, EVA: 3.22 ± 3.27/0.33 ± 1.00/0.023, total MFIS: 44.44 ± 35.91/35 ± 31.70/0.068. In the CG the values were DN4 : 0.38 ± 0.744/2.25 ± 2.71/0.054, EVA : 1.25 ± 1.83/3.63 ± 2.38/0.043, and MFIS : 33.88 ± 21.68/25.13 ± 24.22/0.379. Conclusion: Shiatsu associated with Physiotherapy was effective in improving pain and fatigue in individuals with MS.

A Quality-of-Life Evaluation Study Assessing Health-Related Quality of Life in Patients Receiving Medicinal Cannabis (the QUEST Initiative): Protocol for a Longitudinal Observational Study

Background

Evidence supports several countries introducing legislation to allow cannabis-based medicine as an adjunctive treatment for the symptomatic relief of chronic pain, chemotherapy-induced nausea, spasticity in multiple sclerosis (MS), epileptic seizures, depression, and anxiety. However, clinical trial participants do not represent the entire spectrum of disease and health status seen in patients currently accessing medicinal cannabis in practice.

Objective

This study aims to collect real-world data to evaluate health-related quality of life in patients prescribed medicinal cannabis oil and describe any differences over time, from before starting therapy to after 3 and 12 months of therapy.

Methods

Adult patients newly prescribed medicinal cannabis oil by authorized prescribers and under the Special Access Schemes across Australia will be screened for eligibility and invited to participate. A sample size of 2142 is required, with a 3-month follow-up. All participants will complete the EuroQol 5-Dimension; European Organization for Research and Treatment of Cancer Quality of Life Questionnaire-30; Depression, Anxiety, and Stress Scale-21; Patients’ Global Impression of Change; Patient-Reported Outcomes Measurement Information System (PROMIS) Short Form (SF) version 1.0: Sleep Disturbance 8b; and PROMIS SF Fatigue 13a questionnaires. Patients with chronic pain conditions will also complete the PROMIS SF version 1.0: Pain Intensity 3a and PROMIS SF version 1.0: Pain Interference 8a. Patients with movement disorders will also complete Quality of Life in Neurological Disorders (Neuro-QoL) SF version 1.0: Upper Extremity Function (Fine Motor and Activities of Daily Living) and if chorea is indicated, the Neuro-QoL SF version 2.0: Huntington’s Disease health-related Quality of LIFE-Chorea 6a. All questionnaires will be administered at baseline, 2 weeks (titration), monthly up to 3 months, and then every 2 months up to 1 year.

Results

Recruitment commenced in November 2020. By June 2021, 1095 patients were screened for the study by 69 physicians in centers across 6 Australian states: Australian Capital Territory, New South Wales, Queensland, South Australia, Victoria, and Western Australia. Of the patients screened, 833 (39% of the target sample size) provided consent and completed baseline questionnaires. Results are expected to be published in 2022. Results of this study will show whether patient-reported outcomes improve in patients accessing prescribed medicinal cannabis from baseline to 3 months and whether any changes are maintained over a 12-month period. This study will also identify differences in improvements in patient-reported outcomes among patients with different chronic conditions (eg, chronic pain, MS, epilepsy, Parkinson disease, or cancer).

Conclusions

This protocol contains detailed methods that will be used across multiple sites in Australia. The findings from this study have the potential to be integral to treatment assessment and recommendations for patients with chronic pain and other health indicators for accessing medicinal cannabis.

Trial Registration

Australian New Zealand Clinical Trials Registry: ANZCTRN12621000063819; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=380807&isReview=true

International Registered Report Identifier (IRRID)

DERR1-10.2196/32327

Crotalphine Attenuates Pain and Neuroinflammation Induced by Experimental Autoimmune Encephalomyelitis in Mice

Multiple sclerosis (MS) is a demyelinating disease of inflammatory and autoimmune origin, which induces sensory and progressive motor impairments, including pain. Cells of the immune system actively participate in the pathogenesis and progression of MS by inducing neuroinflammation, tissue damage, and demyelination. Crotalphine (CRO), a structural analogue to a peptide firstly identified in Crotalus durissus terrificus snake venom, induces analgesia by endogenous opioid release and type 2 cannabinoid receptor (CB2) activation. Since CB2 activation downregulates neuroinflammation and ameliorates symptoms in mice models of MS, it was presently investigated whether CRO has a beneficial effect in the experimental autoimmune encephalomyelitis (EAE). CRO was administered on the 5th day after immunization, in a single dose, or five doses starting at the peak of disease. CRO partially reverted EAE-induced mechanical hyperalgesia and decreased the severity of the clinical signs. In addition, CRO decreases the inflammatory infiltrate and glial cells activation followed by TNF-α and IL-17 downregulation in the spinal cord. Peripherally, CRO recovers the EAE-induced impairment in myelin thickness in the sciatic nerve. Therefore, CRO interferes with central and peripheral neuroinflammation, opening perspectives to MS control.

Periorbital Nociception in a Progressive Multiple Sclerosis Mouse Model Is Dependent on TRPA1 Channel Activation

Headaches are frequently described in progressive multiple sclerosis (PMS) patients, but their mechanism remains unknown. Transient receptor potential ankyrin 1 (TRPA1) was involved in neuropathic nociception in a model of PMS induced by experimental autoimmune encephalomyelitis (PMS-EAE), and TRPA1 activation causes periorbital and facial nociception. Thus, our purpose was to observe the development of periorbital mechanical allodynia (PMA) in a PMS-EAE model and evaluate the role of TRPA1 in periorbital nociception. Female PMS-EAE mice elicited PMA from day 7 to 14 days after induction. The antimigraine agents olcegepant and sumatriptan were able to reduce PMA. The PMA was diminished by the TRPA1 antagonists HC-030031, A-967079, metamizole and propyphenazone and was absent in TRPA1-deficient mice. Enhanced levels of TRPA1 endogenous agonists and NADPH oxidase activity were detected in the trigeminal ganglion of PMS-EAE mice. The administration of the anti-oxidants apocynin (an NADPH oxidase inhibitor) or alpha-lipoic acid (a sequestrant of reactive oxygen species), resulted in PMA reduction. These results suggest that generation of TRPA1 endogenous agonists in the PMS-EAE mouse model may sensitise TRPA1 in trigeminal nociceptors to elicit PMA. Thus, this ion channel could be a potential therapeutic target for the treatment of headache in PMS patients.

Subgroup Analysis of Individuals with Multiple Sclerosis Showing Cognitive Resilience

OBJECTIVE

Cognitive dysfunction is known to occur in many individuals with multiple sclerosis (MS). However, little is currently known about MS patients without cognitive impairment, including protective factors associated with intact cognition. The present study considered these issues in a sample of MS patients screened for intact subjective and objective cognitive functioning.

METHODS

Two MS participant groups from a larger sample were derived: i) participants within 1 standard deviation of controls on measures of objective cognition, subjective cognition, and informant-observed subjective cognition [cognitively resilient MS group (MScr)], and ii) those classified as not cognitively resilient (MSncr). Both groups were compared with age- and gender-matched controls.

RESULTS

Findings indicated that the MScr group was similar to the MSncr group on most disease and demographic variables, and level of fatigue. The MScr group showed higher estimated baseline intellectual ability and reported less anxiety, subclinical depressive symptoms, and pain interference. MScr participants also showed a trend toward more reported compensatory cognitive strategy use than MSncr participants. The MScr group showed comparable reading recognition and pain symptoms to controls.

CONCLUSIONS

Our findings provide preliminary information on factors associated with cognitive resilience in MS. Future research should examine resilient individuals with MS to further clarify positive outcomes in this condition.

The epidemiology of primary headaches in patients with multiple sclerosis

OBJECTIVE

Recent studies have shown a pathophysiologic link between headache and multiple sclerosis (MS), but the prevalence of primary headaches among patients with MS differs substantially across studies. This meta-analysis aimed to comprehensively gather available evidence to estimate the prevalence of primary headaches among patients with MS.

METHOD

We systematically searched the electronic databases including PubMed, Embase, and Scopus for cohort, case-control, cross-sectional studies that measured the prevalence of headache among patients with MS. Two reviewers independently screened titles and abstracts to identify the eligible studies and the full texts of the included studies were reviewed. Newcastle-Ottawa Scale (NOS) was used to assess the risk of bias of the included literatures. We then conducted a meta-analysis using Stata Software 15.0 to calculate the pooled prevalence of headaches among patients with MS and assess the source of heterogeneity.

RESULTS

We identified 16 eligible studies covering a total of 3,560 patients with MS. The pooled estimated prevalence of primary headaches among patients with MS was 56%. The statistical heterogeneity was moderate with I² of 82.1% (p < .001). Both a visual inspection of the funnel plot and Egger' regression tests revealed no significant publication bias (p = .44). The pooled estimated prevalence of migraine (55%) was higher in comparison with that of tension-type headache (20%). The prevalence of migraine subtype was 16% and 10% for migraine without aura and migraine with aura, respectively. The pooled prevalence of primary headache in case-control group (57%) was approximately in line with the cross-sectional group (56%).

CONCLUSION

The overall prevalence of primary headaches among patients with MS was considerably high. Clinical screening of headache among patients with MS will be helpful to formulate an individualized treatment plans and alleviate the physical and mental impact of the disease.

Non-invasive Brain and Spinal Stimulation for Pain and Related Symptoms in Multiple Sclerosis: A Systematic Review

Background: Neuropathic and nociceptive pain frequently affect patients with multiple sclerosis (MS), with a prevalence close to 90% and significant impact on general health and quality of life. Pharmacological strategies are widely used to treat pain in MS, but their effectiveness and side-effects are controversial. Among non-pharmacological treatments for pain, non-invasive brain and spinal stimulation (NIBSS) has shown promising preliminary results in MS.

Objective: Systematic review to investigate the effect of NIBSS for the management of pain in MS.

Methods: A literature search using Pubmed, Science Direct and Web of Science was conducted from databases inception to February 21, 2020 for studies assessing the analgesic effect of NIBSS on pain in MS.

Results: A total of 279 records were title- and abstract-screened, nine were assessed for full text and included. The NIBSS techniques explored were transcranial direct current stimulation (N = 5), transcranial magnetic stimulation (N = 2), transcranial random noise stimulation (N =1), transcutaneous spinal direct current stimulation (N = 1). The targets were the primary motor cortex (M1; N = 4), the left dorsolateral pre-frontal cortex (DLPFC; N = 3), the spinal cord (N = 1), unspecified brain target (N = 1). The study designs were randomized (N = 7), open label (N = 1), single case report (N = 1). Despite the differences in study design, target and NIBSS technique that impeded a meta-analysis, all the studies converge in showing a significant improvement of pain after active NIBSS with less consistent effects on other symptoms of the pain-related cluster (depression, fatigue, cognition) and quality of life.

Conclusions: Excitatory NIBSS over M1, left DLPFC and spinal cord appear to be the most effective protocols for pain in MS. Open questions include the use of neurophysiological or neuroimaging surrogate outcome measures, the stratification of patients according to the clinical profiles and underlying pathogenetic mechanisms and the combination of NIBSS to pharmacological treatment, neurorehabilitation, or psychotherapy to improve the clinical effect. The duration of the effect to NIBSS and the feasibility and efficacy of telemedicine NIBSS protocols are other open key questions.

Endoplasmic reticulum stress in the dorsal root ganglia regulates large-conductance potassium channels and contributes to pain in a model of multiple sclerosis

Neuropathic pain is a common symptom of multiple sclerosis (MS) and current treatment options are ineffective. In this study, we investigated whether endoplasmic reticulum (ER) stress in dorsal root ganglia (DRG) contributes to pain hypersensitivity in the experimental autoimmune encephalomyelitis (EAE) mouse model of MS. Inflammatory cells and increased levels of ER stress markers are evident in post-mortem DRGs from MS patients. Similarly, we observed ER stress in the DRG of mice with EAE and relieving ER stress with a chemical chaperone, 4-phenylbutyric acid (4-PBA), reduced pain hypersensitivity. In vitro, 4-PBA and the selective PERK inhibitor, AMG44, normalize cytosolic Ca²⁺ transients in putative DRG nociceptors. We went on to assess disease-mediated changes in the functional properties of Ca²⁺ -sensitive BK-type K⁺ channels in DRG neurons. We found that the conductance-voltage (GV) relationship of BK channels was shifted to a more positive voltage, together with a more depolarized resting membrane potential in EAE cells. Our results suggest that ER stress in sensory neurons of MS patients and mice with EAE is a source of pain and that ER stress modulators can effectively counteract this phenotype.

Central Nervous System Targets: Glial Cell Mechanisms in Chronic Pain

Interactions between central glial cells and neurons in the pain circuitry are critical contributors to the pathogenesis of chronic pain. In the central nervous system (CNS), two major glial cell types predominate: astrocytes and microglia. Injuries or pathological conditions which evoke pain are concurrently associated with the presence of a reactive microglia or astrocyte state, which is characterized by a variety of changes in the morphological, molecular, and functional properties of these cells. In this review, we highlight the changes that reactive microglia and astrocytes undergo following painful injuries and insults and discuss the critical and interactive role these two cell types play in the initiation and maintenance of chronic pain. Additionally, we focus on several crucial mechanisms by which microglia and astrocytes contribute to chronic pain and provide commentary on the therapeutic promise of targeting these pathways. In particular, we discuss how the inflammasome in activated microglia drives maturation and release of key pro-inflammatory cytokines, which drive pain through neuronal- and glial regulations. Moreover, we highlight several potentially-druggable hemichannels and proteases produced by reactive microglia and astrocytes in pain states and discuss how these pathways regulate distinct phases during pain pathogenesis. We also review two emerging areas in chronic pain research: 1) sexually dimorphic glial cell signaling and 2) the role of oligodendrocytes. Finally, we highlight important considerations for potential pain therapeutics targeting glial cell mediators as well as questions that remain in our conceptual understanding of glial cell activation in pain states.