Longitudinal prevalence and determinants of pain in multiple sclerosis: results from the German National Multiple Sclerosis Cohort study

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.

Emotional burden among MS patients: associations between specific chronic pain diagnoses and psychological features

Central neuropathic pain (CNP) and musculoskeletal pain (MSP) are often comorbid with multiple sclerosis (MS), yet data on the emotional burden entailed by this comorbidity are very limited. We studied whether MS patients with CNP exhibited greater emotional burden and pain severity than those with MSP and whether this emotional burden was attributed to the MS, the chronic pain, or both. Participants were 125 MS patients (55 with CNP; 30 with MSP; 40 MS pain-free) and 30 healthy controls (HCs). Participants completed questionnaires assessing pain interference, pain catastrophizing, depression, anxiety, stress, hypervigilance, and chronic pain. Group comparisons and a two-step cluster analysis were performed, and the association between cluster membership and clinical group membership was evaluated. Chronic pain was stronger and more widespread in the CNP group than in the MSP group. Both pain groups had higher pain interference, pain catastrophizing, and stress compared to MS pain-free and HC groups. All MS groups had greater depression levels compared to HCs, and the CNP group had the highest anxiety level. The "high psychological distress" cluster comprised mainly participants with CNP (57%), and the "minimal psychological distress" cluster comprised mainly the MS pain-free and HC groups. In conclusion, CNP seems to induce greater emotional burden and pain severity than does MSP. Whereas depression may be attributed to MS, and anxiety to CNP, enhanced pain interference, catastrophizing, and stress may be attributed to the comorbidity of MS and chronic pain. Identifying these traits among MS patients and targeting them in management programs may contribute to more effective, individually based care.

A systematic review and meta-analysis of neuropathic pain in multiple sclerosis: Prevalence, clinical types, sex dimorphism, and increased depression and anxiety symptoms

Chronic pain is the most disability symptom related to multiple sclerosis (MS) brain lesions and can also generate anxiety and depression. There are no updated reports of the general prevalence of neuropathic pain, MS clinical types, sex dimorphism, and its association with depression and anxiety. The protocol was listed in PROSPERO (CRD42022303571). The article selection resulted in 24 studies with a low risk of bias. The prevalence of neuropathic pain in MS patients was 26.8% with higher levels of depression and anxiety. We also observed that female patients (74.2%) have a higher prevalence of neuropathic pain than males (28.9%). We showed the enhanced prevalence of neuropathic pain using the female and male data (58.9%) compared to the total prevalence (26.8%). In addition, the SPMS (40.3%) presented an increased prevalence of neuropathic pain compared to PPMS (15.6%). Thus, we demonstrated the association between neuropathic pain, depression and anxiety symptoms and the influence of diagnosis, age, disease score, and disease duration in the increased prevalence of neuropathic pain in MS patients.

The Impact of Relapses on Pain and Quality of Life in Patients with Multiple Sclerosis Treated with Corticosteroids

BACKGROUND

We assessed the prevalence and risks associated with pain during and after a multiple sclerosis (MS) relapse, and the impact of pain on quality of life (QoL), in MS patients.

METHODS

117 patients suffering an acute MS relapse were evaluated with clinician- and patient-reported outcomes, including the expanded disability status scale (EDSS), Multiple Sclerosis Impact Scale (MSIS-29), and MS Walking scale-12 (MSWS-12). Relapse-related pain was assessed via the short-form 36 (SF-36) questionnaire upon first visit (relapse onset) and at 6 weeks after treatment with intravenous methylprednisolone (follow-up visit).

RESULTS

Pain was present in 80% of patients at relapse onset. Patients with pain were more impaired physically (higher mean scores on MSIS-29phys and MSWS-12 and lower mean scores on SF-36 role physical, physical, and vitality scales) at relapse and six weeks after. In total, 74% of patients with MS relapse reported a poorer QoL due to pain. A lower psychological well-being was correlated with greater pain (MSIS29psy score). An increased number of prior relapses was a predictor of more pain at relapse onset.

CONCLUSIONS

Pain was common at the time of MS relapse and improved, but was still significant, six weeks after treatment with corticosteroids. Further studies are required to better understand relapse-related pain.

Pain and participation in social activities in people with relapsing remitting and progressive multiple sclerosis

Background

Differences in pain between subtypes of multiple sclerosis are understudied.

Objective

To compare the prevalence of pain, and the association between pain and: (a) pain interference and (b) social participation in people with relapsing-remitting multiple sclerosis and progressive multiple sclerosis.

Methods

Participants completed the McGill Pain Questionnaire Short-Form-2, Pain Effects Scale and Ability to Participate in Social Roles and Activities-V2.0 questionnaires. We tested the association between multiple sclerosis subtype, pain severity, and pain interference/social participation using quantile regression.

Results

Of 231 participants (relapsing-remitting multiple sclerosis: 161, progressive multiple sclerosis: 70), 82.3% were women. The prevalence of pain was 95.2%, of more than mild pain was 38.1%, and of pain-related limitations was 87%; there were no differences between multiple sclerosis subtypes. Compared to participants with relapsing-remitting multiple sclerosis, those with progressive multiple sclerosis reported higher pain interference (mean (standard deviation) Pain Effects Scale; progressive multiple sclerosis: 15[6.0] vs relapsing-remitting multiple sclerosis: 13[5], p = 0.039) and lower social participation (Ability to Participate in Social Roles and Activities T-scores 45[9.0] vs 48.3[8.9], p = 0.011). However, on multivariable analysis accounting for age, physical disability, mood/anxiety and fatigue, multiple sclerosis subtype was not associated with differences in pain interference or social participation.

Conclusions

Pain was nearly ubiquitous. Over one-third of individuals with relapsing-remitting multiple sclerosis and progressive multiple sclerosis reported pronounced pain, although this did not differ by multiple sclerosis subtype.

Pain in patients with multiple sclerosis

Objectives

This study aims to identify the factors associated with pain and neuropathic pain (NP) in patients with multiple sclerosis (MS) and to determine the relationship between pain and NP with disability, functionality, activities of daily living, fatigue, mood, and quality of life (QoL).

Patients and methods

Between July 2017 and October 2017, a total of 100 adult patients with MS (18 males, 82 females; mean age: 35.3±9.9 years; range, 19 to 71 years) were included. All patients were evaluated in terms of pain and NP. Patients with and without pain, and patients with and without NP were compared in terms of sociodemographic characteristics, disease data, disability, functionality, daily living activities, fatigue severity, mood, and QoL using various scales.

Results

A total of 62% of the patients had pain. Pain was found to be associated with low education level (p=0.014), increased fatigue (p<0.001), depressive mood (p<0.001) and lower QoL (p<0.001). A total of 29.03% of patients with pain had NP. Patients with NP had a greater pain intensity (p<0.001) and fatigue (p=0.002) and lower QoL (p=0.011). The number of patients who received the correct treatment for their symptoms was low.

Conclusion

Pain and NP should be better investigated and treated by physicians, as these symptoms are common in MS and adversely affect the QoL and social relations of affected patients and reduce their productivity.

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.

Lower corticospinal excitability and greater fatigue among people with multiple sclerosis experiencing pain

Introduction

Persons with multiple sclerosis (MS) frequently report pain that negatively affects their quality of life. Evidence linking pain and corticospinal excitability in MS is sparse. We aimed to (1) examine differences in corticospinal excitability in MS participants with and without pain and (2) explore predictors of pain.

Methods

Sixty-four participants rated their pain severity on a visual analog scale (VAS). Transcranial magnetic stimulation (TMS) and validated clinical instruments characterized corticospinal excitability and subjective disease features like mood and fatigue. We retrieved information on participants' prescriptions and disability status from their clinical records.

Results

Fifty-five percent of participants reported pain that affected their daily functioning. Persons with pain had significantly greater fatigue and lower area under the excitatory motor evoked potential (MEP) recruitment curve (eREC AUC), a measure of total corticospinal excitability. After controlling for age, disability status, and pain medications, increased fatigue and decreased eREC AUC together explained 40% of the variance in pain.

Discussion

Pain in MS is multifactorial and relates to both greater fatigue and lesser corticospinal excitability. Future work should better characterize relationships between these outcomes to develop targeted pain interventions such as neuromodulation.

Summary

We examined pain in MS. Individuals with pain had higher fatigue and lower corticospinal excitability than those without pain. These outcomes significantly predicted self-reported pain.

Altered bodily perceptions in chronic neuropathic pain conditions and implications for treatment using immersive virtual reality

Chronic neuropathic pain is highly disabling and difficult to treat and manage. Patients with such conditions often report altered bodily perceptions that are thought to be associated with maladaptive structural and functional alterations in the somatosensory cortex. Manipulating these altered perceptions using body illusions in virtual reality is being investigated and may have positive clinical implications for the treatment of these conditions. Here, we have conducted a narrative review of the evidence for the types of bodily distortions associated with a variety of peripheral and central neuropathic pain conditions. In addition, we summarize the experimental and clinical studies that have explored embodiment and body transformation illusions in immersive virtual reality for neuropathic pain relief, which are thought to target these maladaptive changes, as well as suggesting directions for future research.

Antioxidant effect of grape seed extract corrects experimental autoimmune encephalomyelitis behavioral dysfunctions, demyelination, and glial activation

Background and purpose

Multiple sclerosis (MS), a multifactorial autoimmune disease of the central nervous system (CNS), is characterized by demyelination and chronic inflammation, as well as axonal and neuronal loss. There is no cure for MS, and despite a significant improvement in the therapeutic management of patients during the last 20 years, some symptoms are still resistant to treatment, and the evolution of the disease to progressive form seems still ineluctable. The etiology of MS is complex and still not fully understood. However, inflammation is a major driver of physiopathology and oxidative stress contributes to CNS lesions and promotes existing inflammatory response. Plant polyphenols are endowed with many therapeutic benefits through alleviating oxidative stress and inflammation, thus providing neuroprotection in MS. We presently evaluated the curative effect of grape seed extract (GSE) in an experimental autoimmune encephalomyelitis (EAE) mouse model of MS.

Experimental approach

Six-week-old C57Bl/6J females were subjected to the EAE paradigm (using myelin oligodendrocyte glycoprotein peptide fragment (35-55), complete Freund’s adjuvant, and pertussis toxin) and then chronically treated with GSE from day 10 to day 30 post-induction. Clinical score and body weight were monitored daily, while evaluation of sensitive, motor, cognitive, and anxiety-related behaviors was performed weekly. Then, the GSE effect was evaluated on whole brain and spinal cord samples through the evaluation of oxidative stress damage, antioxidant capacities, myelin alteration, astroglial and microglial proliferation, and sirtuin expression.

Key results

Grape seed extract curative chronic treatment corrected the clinical course of EAE, as well as the mechanical hypersensitivity, and avoided the development of EAE mouse thermal cold allodynia. The neuropathological evaluation showed that GSE reduced oxidative stress in the brain and spinal cord by decreasing the lipid and protein oxidation through correction of the three main antioxidant enzyme activities, namely, superoxide dismutase, catalase, and glutathione peroxidase, as well as restoring normal myelin protein expression and correcting microglial and astroglial protein overexpression and sirtuin downregulation.

Conclusion and implications

These data strongly support GSE as an effective therapeutic approach in MS treatment.

The pathophysiology of motor fatigue and fatigability in multiple sclerosis

Multiple Sclerosis (MS) is a heterogeneous immune mediated disease of the central nervous system (CNS). Fatigue is one of the most common and disabling symptom of MS. It interferes with daily activities on the level of cognition and motor endurance. Motor fatigue can either result from lesions in cortical networks or motor pathways (“primary fatigue”) or it may be a consequence of detraining with subsequent adaptions of muscle and autonomic function. Programmed exercise interventions are used frequently to increase physical fitness in MS-patients. Studies investigating the effects of training on aerobic capacity, objective endurance and perceived fatigability have yielded heterogenous results, most likely due to the heterogeneity of interventions and patients, but probably also due to the non-uniform pathophysiology of fatigability among MS-patients. The aim of this review is to summarize the current knowledge on the pathophysiology of motor fatigability with special reference to the basic exercise physiology that underlies our understanding of both pathogenesis and treatment interventions.

Efficacy of Fluoxetine, Riluzole and Amiloride in treating neuropathic pain associated with secondary progressive multiple sclerosis. Pre-specified analysis of the MS-SMART double-blind randomised placebo-controlled trial

BACKGROUND

Evidence-based treatment of pain in people with MS presents a major unmet need.

OBJECTIVE

We aimed to establish if use of Fluoxetine, Riluzole or Amiloride improved neuropathic pain outcomes in comparison to placebo, in adults with secondary progressive MS participating in a trial of these putative neuroprotectants.

METHODS

In pre-specified secondary analyses of the MS SMART phase-2b double-blind randomised controlled trial (NCT01910259), we analyzed reports of neuropathic pain, overall pain, and pain interference. Multivariate analyses included adjustment for baseline pain severity. Additionally, we explored associations of pain severity with clinical and MRI brain imaging variables.

RESULTS

445 Participants were recruited from 13 UK neuroscience centres. We found no statistically significant benefit of active intervention on any rating of neuropathic pain, or pain overall. Compared to placebo, adjusted mean difference in pain intensity was 0.38 (positive values favouring placebo, 95%CI -0.30 to 1.07, p = 0.27) for Amiloride; 0.52 (-0.17 to 1.22, p = 0.14) for Fluoxetine; and 0.40 (-0.30 to 1.10, p = 0.26) for Riluzole. Pain severity was positively correlated with depressive symptoms (Spearman correlation 0.19, 95%CI 0.10-0.28) and fatigue (Rho 0.30, 95%CI 0.20-0.39).

CONCLUSION

Use of Fluoxetine, Riluzole or Amiloride was not associated with improvement in neuropathic pain symptoms, in comparison to placebo.

Unique features of central neuropathic pain in multiple sclerosis: Results of a cluster analysis

Background

Central neuropathic pain (CNP) is an excruciating condition, prevalent in up to a third of patients with multiple sclerosis (MS). Identifying CNP among MS patients is particularly challenging considering the ample comorbid chronic pain conditions and sensory disturbances entailed by the disease. The aim was to identify sensory features unique to CNP beyond those of chronic pain and MS.

Methods

Participants were 112 MS patients: 44 with a diagnosis of CNP, 28 with a diagnosis of chronic musculoskeletal pain (MSP), and 40 pain free. Participants underwent testing of thermal and mechanical thresholds, thermal grill illusion (TGI), pain adaptation (PA), and offset analgesia (OA), and chronic pain was characterized. A two‐step cluster analysis was performed, and the association between the cluster membership and the clinical group membership (CNP, MSP, pain free) was evaluated.

Results

The CNP and MSP groups were similar in most of the chronic pain variables (e.g., severity, location and quality) and MS‐related variables (e.g., type, severity and medication intake). The three created clusters had unique sensory features: (1) ‘Hyposensitivity’ (increased thermal and touch thresholds) characterized the CNP group; (2) ‘Poor inhibition and hyperalgesia’ (worst PA and OA and decreased TGI threshold) characterized the MSP group; and (3) ‘Efficient inhibition’ (best PA and OA, smallest sensory loss) characterized the pain‐free group.

Conclusions

The unique sensory features of CNP and MSP provide insight into their pathophysiology, and evaluating them may increase the ability to provide individually based interventions. Efficient inhibition may protect MS patients from chronic pain.

Significance

Cluster analysis among patients with multiple sclerosis (MS) revealed that while central neuropathic pain is associated with thermal and mechanical hypoesthesia, musculoskeletal pain is involved with reduced pain inhibition and hyperalgesia; sensory profiles that provide insights into the mechanisms of these conditions and may promote an individually based pain management.

Co-occurrence of Fatigue and Depression in People With Multiple Sclerosis: A Mini-Review

Fatigue and depression are common conditions diagnosed in people with multiple sclerosis (MS). Fatigue defined as subjective lack of physical and/or mental energy is present in 35–97% of people with MS, who classify it as one of the most serious symptoms interfering with daily activities and influencing the quality of life. Depression is diagnosed in about 50% of people with MS. Since fatigue and depression frequently coexists, it may be quite hard to differentiate them. Primary fatigue and primary depression in MS are caused by inflammatory, oxidative/nitrosative, and neurodegenerative processes leading to demyelination, axonal damage, and brain atrophy. In people with MS and comorbid fatigue and/or depression there is reported increased serum and cerebrospinal fluid concentration of inflammatory mediators such as tumor necrosis factor, interleukins (IL-1a, IL-1b, IL-6), interferon γ and neopterin. Moreover, the brain atrophy of prefrontal, frontal, parietotemporal regions, thalamus, and basal ganglia was observed in people with MS with fatigue and/or depression. The secondary fatigue and secondary depression in people with MS may be caused by emotional factors, sleep disorders, pain, the coexistence of other diseases, and the use of medications. In some studies, the use of disease-modifying therapies positively influenced fatigue, probably by reducing the inflammatory response, which proves that fatigue and depression are closely related to immunological factors. In this mini-review, the pathogenesis, methods of evaluation and differentiation, and possible therapies for fatigue and depression in MS are discussed.

In-Depth Characterization of Somatic and Orofacial Sensitive Dysfunctions and Interfering-Symptoms in a Relapsing-Remitting Experimental Autoimmune Encephalomyelitis Mouse Model

Among the many symptoms (motor, sensory, and cognitive) associated with multiple sclerosis (MS), chronic pain is a common disabling condition. In particular, neuropathic pain symptoms are very prevalent and debilitating, even in early stages of the disease. Unfortunately, chronic pain still lacks efficient therapeutic agents. Progress is needed (i) clinically by better characterizing pain symptoms in MS and understanding the underlying mechanisms, and (ii) preclinically by developing a more closely dedicated model to identify new therapeutic targets and evaluate new drugs. In this setting, new variants of experimental autoimmune encephalomyelitis (EAE) are currently developed in mice to exhibit less severe motor impairments, thereby avoiding confounding factors in assessing pain behaviors over the disease course. Among these, the optimized relapsing-remitting EAE (QuilA-EAE) mouse model, induced using myelin oligodendrocyte glycoprotein peptide fragment (35–55), pertussis toxin, and quillaja bark saponin, seems very promising. Our study sought (i) to better define sensitive dysfunctions and (ii) to extend behavioral characterization to interfering symptoms often associated with pain during MS, such as mood disturbances, fatigue, and cognitive impairment, in this optimized QuilA-EAE model. We made an in-depth characterization of this optimized QuilA-EAE model, describing for the first time somatic thermal hyperalgesia associated with mechanical and cold allodynia. Evaluation of orofacial pain sensitivity showed no mechanical or thermal allodynia. Detailed evaluation of motor behaviors highlighted slight defects in fine motor coordination in the QuilA-EAE mice but without impact on pain evaluation. Finally, no anxiety-related or cognitive impairment was observed during the peak of sensitive symptoms. Pharmacologically, as previously described, we found that pregabalin, a treatment commonly used in neuropathic pain patients, induced an analgesic effect on mechanical allodynia. In addition, we showed an anti-hyperalgesic thermal effect on this model. Our results demonstrate that this QuilA-EAE model is clearly of interest for studying pain symptom development and so could be used to identify and evaluate new therapeutic targets. The presence of interfering symptoms still needs to be further characterized.

The Problem of Pain in Systemic Lupus Erythematosus: An Explication of the Role of Biopsychosocial Mechanisms

OBJECTIVE

To define biopsychosocial mechanisms of pain that go above and beyond disease activity and organ damage in systemic lupus erythematosus (SLE).

METHODS

We conducted a cross-sectional analysis of patient-reported data in a population-based registry of 766 people with SLE. Predictors of pain intensity and interference were examined using hierarchical linear regression. We built 2 main hierarchical regression models with pain intensity and interference as outcomes, both regressed on disease activity and organ damage. For each model, we sought to establish the relationship between pain outcomes and the primary exposures using sequential steps comprising the inclusion of each construct in 6 stages: demographic, socioeconomic, physical, psychological, behavioral, and social factors. We also conducted sensitivity analyses eliminating all overt aspects of pain in the disease activity measure and reestimated the models.

RESULTS

Disease activity and organ damage explained 32-33% of the variance in pain intensity and interference. Sociodemographic factors accounted for an additional 4-9% of variance in pain outcomes, whereas psychosocial/behavioral factors accounted for the final 4% of variance. In the sensitivity analyses, we found that disease activity and organ damage explained 25% of the variance in pain outcomes.

CONCLUSION

Disease activity only explained 33% of the variance in pain outcomes. However, there was an attenuation in these associations after accounting for psychosocial/behavioral factors, highlighting their roles in modifying the relationship between disease activity and pain. These findings suggest that multilevel interventions may be needed to tackle the negative effect of pain in SLE.

[Pain in multiple sclerosis and neuromyelitis optica spectrum disorders]

Multiple sclerosis and neuromyelitis optica spectrum disorders are autoimmune inflammatory diseases of the central nervous system, which can lead to a multitude of neurological complaints and pain syndromes. Pain may be an acute symptom during disease exacerbation as well as a chronic symptom, whereby the latter sometimes substantially reduces the quality of life. The etiology of pain is very heterogeneous but the rapid differential diagnostic classification is decisive in order to be able to initiate a differentiated treatment strategy. Chronic pain must be differentiated from pain as a possible (early) symptom of an acute disease exacerbation, classified in more detail and individually treated. These include central neuropathic pain, pain associated with spasticity, musculoskeletal pain due to excess loading and pain as a side effect of immunotherapy and in the context of comorbidities. The treatment strategies are often insufficiently evidence-based due to the lack of data.

Toll-like receptor 2 and 4 antagonism for the treatment of experimental autoimmune encephalomyelitis (EAE)-related pain

Neuropathic pain is a major symptom of multiple sclerosis (MS) with up to 92% of patients reporting bodily pain, and 85% reporting pain severe enough to cause functional disability. None of the available therapeutics target MS pain. Toll-like receptors 2 and 4 (TLR2/TLR4) have emerged as targets for treating a wide array of autoimmune disorders, including MS, as well as having demonstrated success at suppressing pain in diverse animal models. The current series of studies tested systemic TLR2/TLR4 antagonists in males and females in a low-dose Myelin oligodendrocyte glycoprotein (MOG) experimental autoimmune encephalomyelitis (EAE) model, with reduced motor dysfunction to allow unconfounded testing of allodynia through 50+ days post-MOG. The data demonstrated that blocking TLR2/TLR4 suppressed EAE-related pain, equally in males and females; upregulation of dorsal spinal cord proinflammatory gene expression for TLR2, TLR4, NLRP3, interleukin-1β, IkBα, TNF-α and interleukin-17; and upregulation of dorsal spinal cord expression of glial immunoreactivity markers. In support of these results, intrathecal interleukin-1 receptor antagonist reversed EAE-induced allodynia, both early and late after EAE induction. In contrast, blocking TLR2/TLR4 did not suppress EAE-induced motor disturbances induced by a higher MOG dose. These data suggest that blocking TLR2/TLR4 prevents the production of proinflammatory factors involved in low dose EAE pathology. Moreover, in this EAE model, TLR2/TLR4 antagonists were highly effective in reducing pain, whereas motor impairment, as seen in high dose MOG EAE, is not affected.

Pain, depression, and quality of life in adults with MOG-antibody-associated disease

BACKGROUND AND PURPOSE

Myelin oligodendrocyte glycoprotein-antibody-associated disease (MOGAD) is an inflammatory autoimmune condition of the central nervous system. However, data on pain and depression have remained scarce. The aim of this study was to assess features of chronic pain and depression as well as their impact on health-related quality of life (hr-QoL) in MOGAD.

METHODS

Patients with MOGAD were identified in the Neuromyelitis Optica Study Group registry. Data were acquired by a questionnaire, including clinical, demographic, pain (PainDetect, Brief Pain Inventory-Short Form, McGill Pain Questionnaire-Short Form), depression (Beck Depression Inventory-II), and hr-QoL (Short Form-36 Health Survey) items.

RESULTS

Twenty-two of 43 patients suffered from MOGAD-related pain (11 nociceptive, eight definite neuropathic, three possible neuropathic) and 18 from depression. Patients with neuropathic pain had the highest pain intensity and most profound activities of daily living (ADL) impairment. Fifteen patients reported spasticity-associated pain, including four with short-lasting painful tonic spasms. Later disease onset, profound physical impairment, and depression were associated with chronic pain. Physical QoL was more affected in pain sufferers (p < 0.001) than in pain-free patients, being most severely reduced by neuropathic pain (p = 0.016). Pain severity, visual impairment, and gait impairment independently predicted lower physical QoL. Depression was the only factor reducing mental QoL. Twelve patients still suffering from moderate pain (pain severity 4.6 ± 2.3) received pain medication. Only four out of 10 patients with moderate to severe depression took antidepressants.

CONCLUSIONS

Being highly prevalent, pain and depression strongly affect QoL and ADL in MOGAD. Both conditions remain insufficiently controlled in real-life clinical practice.

Identifying Early Neuropsychological Indicators of Cognitive Involvement in Multiple Sclerosis

Multiple sclerosis (MS) is a debilitating disease of the central nervous system that is most commonly seen in early to middle adulthood, although it can be diagnosed during childhood or later in life. While cognitive impairment can become more prevalent and severe as the disease progresses, signs of cognitive involvement can be apparent in the early stages of the disease. In this review, we discuss the prevalence and types of cognitive impairment seen in early MS, including the specific measures used to identify them, as well as the challenges in characterizing their frequency and progression. In addition to examining the progression of early cognitive involvement over time, we explore the clinical factors associated with early cognitive involvement, including demographics, level of physical disability, disease modifying therapy use, vocational status, and psychological and physical symptoms. Given the prevalence and functional impact these impairments can have for persons with MS, considerations for clinicians are provided, such as the role of early cognitive screenings and the importance of comprehensive neuropsychological assessments.

The risk of polypharmacy, comorbidities and drug-drug interactions in women of childbearing age with multiple sclerosis

Background and Aims

Multiple sclerosis (MS) is the most common neuroimmunological disease of the central nervous system in young adults. Despite recommended contraception, unplanned pregnancies can occur in women of childbearing age with MS. MS- and comorbidities-related multimedication in these patients represents a potential risk. We aimed to raise awareness regarding the frequency of polypharmacy and drug-drug interactions (DDIs) in female MS patients of childbearing age.

Methods

Sociodemographic, clinical and pharmaceutical data were collected through patient records, clinical investigations and structured patient interviews of 131 women with MS. The clinical decision support software MediQ was used to identify potential DDIs. A medication and DDI profile of the study population was created by statistical analysis of the recorded data.

Results

Of the 131 female MS patients, 41.2% were affected by polypharmacy (concurrent use of ⩾5 drugs). Polypharmacy was associated with higher age, higher degree of disability, chronic progressive MS disease course and comorbidities. With an average intake of 4.2 drugs per patient, a total of 1033 potential DDIs were identified. Clinically relevant DDIs were significantly more frequent in patients with polypharmacy than in patients without polypharmacy (31.5% versus 5.2%; Fisher's exact test: p < 0.001).

Conclusion

For the first time, a comprehensive range of potential DDIs in women of childbearing age with MS is presented. Polypharmacy is associated with the occurrence of clinically relevant DDIs. This shows the need for effective and regular screening for such interactions in order to prevent avoidable adverse effects.

Fatigue, depression, and pain in multiple sclerosis: How neuroinflammation translates into dysfunctional reward processing and anhedonic symptoms

Fatigue, depression, and pain affect the majority of multiple sclerosis (MS) patients, which causes a substantial burden to patients and society. The pathophysiology of these symptoms is not entirely clear, and current treatments are only partially effective. Clinically, these symptoms share signs of anhedonia, such as reduced motivation and a lack of positive affect. In the brain, they are associated with overlapping structural and functional alterations in areas involved in reward processing. Moreover, neuroinflammation has been shown to directly impede monoaminergic neurotransmission that plays a key role in reward processing. Here, we review recent neuroimaging and neuroimmunological findings, which indicate that dysfunctional reward processing might represent a shared functional mechanism fostering the symptom cluster of fatigue, depression, and pain in MS. We propose a framework that integrates these findings with a focus on monoaminergic neurotransmission and discuss its therapeutic implications, limitations, and perspectives.

Sensory and pain modulation profiles of ongoing central neuropathic extremity pain in multiple sclerosis

BACKGROUND

Central neuropathic extremity pain (CNEP) is the most frequent type of pain in multiple sclerosis (MS). The aim of the present study was to evaluate sensory and pain modulation profiles in MS patients with CNEP.

METHODS

In a single-centre observational study, a group of 56 CNEP MS patients was compared with 63 pain-free MS patients and with a sex- and age-adjusted control group. Standardized quantitative sensory testing (QST) and dynamic QST (dQST) protocols comprising temporal summation and conditioned pain modulation tests were used to compare sensory profiles.

RESULTS

Loss-type QST abnormalities in both thermal and mechanical QST modalities prevailed in both MS subgroups and correlated significantly with higher degree of disability expressed as Expanded Disability Status Scale (EDSS). Comparison of sensory phenotypes disclosed a higher frequency of the 'sensory loss' prototypic sensory phenotype in the CNEP subgroup (30%) compared with pain-free MS patients (6%; p = .003).

CONCLUSION

The role of aging process and higher lesion load in the spinothalamocortical pathway might be possible explanation for pain development in this particular 'deafferentation' subtype of central neuropathic pain in MS. We were unable to support the role of central sensitization or endogenous facilitatory and inhibitory mechanisms in the development of CNEP in MS.

SIGNIFICANCE

This article presents higher prevalence of the 'sensory loss' prototypic sensory phenotype in multiple sclerosis patients with central extremity neuropathic pain compared to pain-free patients. Higher degree of disability underlines the possible role of higher lesion load in the somatosensory pathways in this particular 'deafferentation' type of central neuropathic pain.

Clinical perspective on pain in multiple sclerosis

Pain is an important and frequent symptom in multiple sclerosis (MS), which leads to a low quality of life, increased disability level, and lack of employment and mental health. Recently, studies have shown increased interest in pain in MS and there is a growing evidence of its prevalence. However, the literature suffers from lack of experimental studies focusing on pain reduction. This topical review summarizes the current knowledge about pain in MS with its definitions, assessments, treatments and rehabilitation within a holistic perspective.