Migraine headaches and pain with neuropathic characteristics: Comorbid conditions in patients with multiple sclerosis

Migraine and Tension-Type Headache Are Associated with Multiple Sclerosis: A Case-Control Study

Background/Objectives: Over the past few decades, there has been increased scientific interest in the prevalence of headache disorders among people with MS (pwMS). Although the latest data suggest an association between migraine and multiple sclerosis, studies have been providing inconsistent results largely due to methodological differences, including small sample sizes, lack of control groups, absence of structured headache diaries, and variability in diagnostic criteria. This study aims to address the question of whether pwMS have a higher prevalence of primary headache disorders than healthy controls (HCs) and whether MS is associated with an increased risk of headaches. Methods: In this cross-sectional, case-control study, consecutive pwMS from Eginition University Hospital, Athens, Greece, along with matched HCs, were recruited. Both groups were assessed for headache disorders, over the past 3 months from the day of recruitment, using a semi-structured questionnaire and diagnosed according to the International Classification for Headache Disorders 3 (ICHD-3) criteria. A multivariable logistic regression model adjusted for age and sex evaluated the association between MS and headache disorders. Results: Ninety-six pwMS and ninety-six matched HCs met the inclusion criteria and were enrolled in the study. A higher prevalence of primary headache disorders in pwMS (71.9%) compared to HCs (43.8%) was observed. Specifically, 28.1% of pwMS had migraine, and 38.5% had tension-type headache (TTH). PwMS were significantly more likely to be diagnosed with any primary headache disorder (OR = 4.54; 95% CI: 2.28 to 9.04; p = 1.7), migraine (OR = 2.21 95% CI: 1.05 to 4.62; p < 0.05), and TTH (OR = 2.16 95% CI: 1.16 to 4; p < 0.05) compared to HCs. Conclusions: Our study suggests that primary headache disorders are more prevalent in pwMS in a cohort recruited from the MS outpatient clinic at Eginition University Hospital in Athens, Greece, compared to the general population and highlights the need for targeted headache management within this group. Prospective longitudinal studies are needed to draw more robust conclusions on a potential association and its underlying mechanisms.

Effects of multiple transcranial magnetic stimulation sessions on pain relief in patients with chronic neuropathic pain: A French cohort study in real-world clinical practice

BACKGROUND

Current clinical trials indicate that repetitive transcranial magnetic stimulation (rTMS) is effective in reducing drug-resistant neuropathic pain (NP). However, there is a lack of studies evaluating the long-term feasibility and clinical efficacy of rTMS in large patient cohorts in real-world conditions.

METHODS

In this retrospective cohort study, we analysed 12 years of clinical data to assess the long-term analgesic effects of 20 Hz rTMS over the primary motor cortex in patients with NP. Subgroup analyses were conducted to identify predictive factors and assess the potential role of epidural motor cortex stimulation (eMCS) as a sustained solution.

RESULTS

In total, 193 patients completed test period of 4 rTMS sessions and 42% of them reported a pain relief (PR) greater than 30%, with concurrent improvement in their most disabling symptom. Iterative rTMS sessions maintained analgesic effects over 10 years in certain patients identified as responders (≥10% PR) without adverse effects. Success probability was higher in patients with central NP compared to peripheral NP (OR = 2.03[1.04;4.00]), and among those with central post-stroke pain, this probability was higher in ischemic versus hemorrhagic strokes (OR = 3.36[1.17;10.05]). PR obtained with iterative rTMS sessions was an excellent predictor of eMCS efficacy.

CONCLUSIONS

While rTMS shows promise as a therapeutic option for some patients with drug-resistant NP, it does not benefit all patients. Efficacy varies by NP aetiology, aiding patient selection. For responders, eMCS may offer a permanent solution. These findings support a tailored approach to rTMS in NP management, while recognizing both its potential and limitations across diverse patient profiles.

SIGNIFICANCE STATEMENT

Multiple rTMS sessions demonstrate long-term efficacy and safety in treating drug-resistant neuropathic pain. Extending session numbers for the test period can enhance responder identification, especially in patients with initial low pain relief. This identification refines patient selection for neurosurgery, reducing non-responders. Central neuropathic pain shows higher success rates than peripheral. For post-stroke central pain, patients with ischemic stroke are more likely to respond than those with hemorrhagic stroke. These results support integrating rTMS into clinical practice for managing neuropathic pain.

Headache disorders in multiple sclerosis: Is there an association? A systematic review and meta-analysis

OBJECTIVE

To look for any potential association of headache disorders with multiple sclerosis (MS).

BACKGROUND

The prevalence of headache disorders has been found to be increased in people with MS (pwMS), however, an association has not been established. Existing studies have provided conflicting results mostly because of methodological differences.

METHODS

PubMed, Embase and Scopus were searched to identify eligible studies. Studies were included if they were cross-sectional, case-control or cohort. Newcastle-Ottawa Scale (NOS) was used to assess the risk of bias of the included studies. Case-control, cross sectional or cohort studies that used the International Classification of Headache Disorders (ICHD)-2 or-3 criteria for headache diagnosis and Mc Donald or Poser criteria for MS diagnosis were included. Data were extracted using standardized data collection form. Meta-analysis was conducted by calculating the overall prevalence of headache disorders in pwMS as well as the association of headache disorders with MS. The Newcastle-Ottawa Scale (NOS), a tool for assessing the quality of non-randomized studies, was used to assess the quality of the included studies.

RESULTS

Twenty-three studies were included yielding a total of 5,440 MS patients and 28,0958 controls. The majority of them scored a NOS score between 5 and 6 (max 9), which indicates that they did not rank high in terms of quality, because most studies were cross-sectional and uncontrolled, and only one was prospective, controlled, and longitudinal, but with small population size. Pooled prevalence for all headache disorders, migraine and tension-type headache (TTH) in pwMS was 58 % (95 % CI 0.54-0.61), 30 % (95 % CI 0.25-0.34) and 19 % (95 % CI 0.15-0.23) respectively. A significant association between migraine and MS was found (OR = 2.02, 95 % CI = 1.14-3.57).

CONCLUSION

PwMS are twice as likely to experience migraine as controls, but the results need to be translated with caution since most of the studies included in the meta-analysis were of low or moderate quality. Larger prospective cohort, controlled, longitudinal studies are needed to confirm whether there is indeed an association between MS and migraine.

Increased Prevalence of Headaches and Migraine in Patients with Psoriatic Arthritis and Axial Spondyloarthritis: Insights from an Italian Cohort Study

BACKGROUND

Psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA) are inflammatory diseases with shared genetic backgrounds and clinical comorbidities. Headache, a common global health issue, affects over 50% of adults and encompasses various types, including migraine, tension-type, and cluster headaches. Migraine, the most prevalent, recurrent, and disabling type, is often associated with other medical conditions such as depression, epilepsy, and psoriasis, but little is known about the relationship between autoimmune disease and the risk of migraine.

METHODS

A cross-sectional study was conducted from July to November 2022, enrolling 286 participants, including 216 with PsA, 70 with axSpA, and 87 healthy controls.

RESULTS

Headache prevalence was significantly higher in the PsA (39.81%) and axSpA (45.71%) patients compared to the healthy controls. The prevalence of migraine without aura was also significantly higher in both the PsA (18.52%) and axSpA (28.57%) groups compared to the healthy controls.

CONCLUSIONS

These findings underscore the high burden of headache and migraine in PsA and axSpA participants, highlighting the need for improved management and treatment strategies for these patients.

Risk factors of neuropathic pain in multiple sclerosis: a retrospective case-cohort study

Background

Pain is a common symptom in multiple sclerosis (MS), especially neuropathic pain, which has a significant impact on patients' mental and physical health and quality of life. However, risk factors that related to neuropathic pain, still remain unclear.

Objective

The study aimed to explore the risk factors of neuropathic pain among MS patients.

Materials and methods

This retrospective study examined the consecutive patients diagnosed with MS in the Department of Neurology of Guangdong Provincial Hospital of Chinese Medicine between August 2011 and October 2022. Neuropathic pain was defined as "pain arising as a direct consequence of a lesion or disease affecting the somatosensory system". Demographic and clinical features were obtained from the electronic system of the hospital.

Results

Our cohort revealed that the prevalence of patients with neuropathic pain in MS was 34.1%. The results indicated that the longer the spinal lesions, the greater the neuropathic pain risks (2-4: OR, 13.3(2.1-82), >5: OR, 15.2(2.7-86.8), p for tread: 0.037). Meanwhile, multivariate regression analysis showed that cervical and thoracic lesions (OR 4.276, 95% CI 1.366-13.382, P = 0.013), upper thoracic lesions (T1-T6) (OR 3.047, 95% CI 1.018-9.124, P = 0.046) were positively correlated with neuropathic pain, while basal ganglia lesions (OR 0.188, 95% CI 0.044-0.809, P = 0.025) were negatively correlated with neuropathic pain among MS patients.

Conclusion

Extended spinal lesions (≥3 spinal lesions), cervical and thoracic lesions, upper thoracic lesions were independent risk factors of neuropathic pain among MS patients. Furthermore, our study found that the longer the spinal lesions, the greater the neuropathic pain risks.

Headache and Other Pain Syndromes in Multiple Sclerosis: A Narrative Review

Multiple sclerosis is a chronic and progressive neurological disease, with an important socio-economic burden. Over time, an increased incidence of headaches like migraines and tension headaches has been observed among these patients. Headaches have not been considered as multiple sclerosis-related symptoms, even representing a red flag for multiple sclerosis diagnosis. It is uncertain whether the headache-multiple sclerosis association could be explained by the presence of common triggers or a common physiopathological mechanism (involvement of tertiary B-cell follicles). An important differential diagnosis is between multiple sclerosis attacks and migraines with aura, which can also be associated with neurological deficits. Another important aspect is the occurrence or exacerbation of the cephalalgic syndrome after the initiation of therapy for multiple sclerosis (DMTs), or the improvement of headache after the initiation of certain DMT drugs. In addition to headaches, individuals diagnosed with multiple sclerosis often report experiencing diverse pain syndromes, contributing to an additional decline in their overall quality of life. These syndromes are frequently neglected, the focus being on slowing down the progression of neurological deficits. This review aims to evaluate the characteristics of multiple-sclerosis-related headaches (frequency, possible correlation with attacks, and disease-modifying therapies) and the key distinctions in imaging characteristics between demyelinating lesions in multiple sclerosis and those observed in cases of primary headaches.

Comorbid conditions in Egyptian patients with migraine

BACKGROUND

Identifying migraine comorbidities may guide prognosis and treatment options. This study aimed to assess the frequency of comorbid conditions among adults with migraine living in Greater Cairo.

METHODS

In this cross-sectional study, Egyptian migraine sufferers aged ≥ 18 years living in Greater Cairo were consecutively recruited (April 2019 - April 2021). Following The International Classification of Headache Disorders-third edition, diagnosis of migraine was confirmed, and the type of migraine was defined as whether episodic or chronic, with or without aura, with childhood/adolescence or adulthood onset. Specialist physicians from the research team assessed comorbid conditions among the respondents.

RESULTS

The mean age of respondents (n = 1064) was 35 ± 7. Irritable bowel syndrome represented the most common comorbidity in our patients (45.5%), followed by vitamin D deficiency (41.8%). The frequency of epilepsy, stroke, multiple sclerosis, and systemic lupus erythematosus was significantly higher in patients with chronic than episodic type (χ2 = 4.514, P = 0.034), (χ2 = 12.302, P = 0.001), (χ2 = 12.302, P = 0.001), (χ2 = 4.806, P 0.028), respectively. Females with menstrual migraines had a significantly higher frequency of generalized anxiety disorder, panic attacks, and restless leg syndrome than those with non-menstrual migraines (χ2 = 7.636, P 0.006), (χ2 = 9.245, P = 0.002), and (χ2 = 11.997, P = 0.001), respectively. The frequency of diabetes was significantly higher in patients with migraine with aura than in those without aura (χ2 = 4.248, P value 0.039).

CONCLUSION

This study provides a better understanding of the comorbidities in Egyptian patients with migraine and will provide new avenues for developing individualized therapy for migraine patients.

The association between multiple sclerosis and migraine: A meta-analysis

BACKGROUND

Multiple sclerosis (MS) is a chronic progressive condition marked by the deterioration of myelin and impairment of neurological function. The global prevalence of MS is approximately 2.2 million. Migraines are common in MS patients, with inconclusive data on their relationship. Our systematic review aimed to assess the prevalence and odds of migraine in pwMS and investigate the potential factors that may influence these associations.

METHOD

Through an extensive search and meticulous study selection, we identified pertinent literature investigating the occurrence and odds of migraines among pwMS. Additionally, we explored the comparative risk of migraines in MS patients compared to healthy controls. Data were extracted, including publication details, diagnostic criteria, and migraine prevalence in MS patients.

RESULTS

A total of 35 studies were included, involving 279,620 pwMS and 279,603 healthy controls. The overall prevalence of migraine in pwMS was 0.24 (95% CI: 0.21-0.28). Subgroup analyses and meta-regression were conducted to investigate the potential impact of various factors on the relationship between migraine and MS. These factors included age, duration of MS, study design, and the Expanded Disability Status Scale (EDSS), migraine diagnosis method, study design, publication year of the study, country and continent of the study population. The results of these analyses revealed no significant influence of these factors on the relationship between migraine and MS. The meta-analysis indicated that pwMS had significantly increased odds of having migraine compared to healthy controls (OR = 1.96, 95% CI: 1.20-3.20). Sensitivity analyses supported the robustness of the findings.

CONCLUSIONS

Our study highlights that approximately 24% of pwMS experience migraine. The method of diagnosis significantly affects the reported prevalence, with questionnaires yielding higher rates. Furthermore, pwMS have a 1.96-fold increased odds of having migraine compared to healthy individuals. These findings emphasize the importance of further research and interventions to address the significant burden of migraine in the MS population.

Pain in Parkinson disease: mechanistic substrates, main classification systems, and how to make sense out of them

ABSTRACT

Parkinson disease (PD) affects up to 2% of the general population older than 65 years and is a major cause of functional loss. Chronic pain is a common nonmotor symptom that affects up to 80% of patients with (Pw) PD both in prodromal phases and during the subsequent stages of the disease, negatively affecting patient's quality of life and function. Pain in PwPD is rather heterogeneous and may occur because of different mechanisms. Targeting motor symptoms by dopamine replacement or with neuromodulatory approaches may only partially control PD-related pain. Pain in general has been classified in PwPD according to the motor signs, pain dimensions, or pain subtypes. Recently, a new classification framework focusing on chronic pain was introduced to group different types of PD pains according to mechanistic descriptors: nociceptive, neuropathic, or neither nociceptive nor neuropathic. This is also in line with the International Classification of Disease-11 , which acknowledges the possibility of chronic secondary musculoskeletal or nociceptive pain due to disease of the CNS. In this narrative review and opinion article, a group of basic and clinical scientists revise the mechanism of pain in PD and the challenges faced when classifying it as a stepping stone to discuss an integrative view of the current classification approaches and how clinical practice can be influenced by them. Knowledge gaps to be tackled by coming classification and therapeutic efforts are presented, as well as a potential framework to address them in a patient-oriented manner.

Profiling the Spectrum of Headache Disorders on 440 Breast Cancer Patients: Highlights on Clinical and Pathological Mechanisms

Although widely studied, the association between migraines (M) and breast cancer (BC) risk remains evasive. In this prospective single-center study, 440 early or locally advanced BC patients were enrolled at IRCCS Humanitas Research Hospital. Clinical and demographical data were collected. Those who suffered from headaches were evaluated with the International Classification of Headache Disorders. M was found to be significantly more prevalent in BC patients: 56.1% versus an expected prevalence of 17% in the global population. M patients showed a higher risk of having stage II or III BC than stage I, which was more frequently found in the non-headache population. Interestingly, the frequency of headache attacks was positively correlated with estrogen (r = 0.11, p = 0.05) and progesterone (r = 0.15, p = 0.007) expression, especially in patients with migraine without aura. The higher the expression of hormone receptors in BC, the higher the headache frequency. Moreover, patients suffering from headaches showed an overall earlier onset of BC. Our findings challenge the idea of a net preventive role of M on BC, suggesting a rather complex interaction in which M mostly influences some BC subtypes and vice versa. Further multi-center studies with extended follow-up are needed.

Multiple sclerosis and migraine: Links, management and implications

Multiple sclerosis (MS) is a chronic inflammatory disease leading to multifocal neuronal demyelination and axonal damage in the central nervous system (CNS). MS symptoms vary widely but typically do not include headaches. A large spectrum of headaches manifestations was reported as comorbidities in MS and results in additional disability. Migraine, tension-type headache and cluster headache are the most frequently reported primary headache syndromes in patients with MS (pwMS). Secondary causes of headache should be excluded (cerebral vein thrombosis, CNS or systemic infection, cervical and/or cranial trauma, headaches associated with psychiatric disorders, medication overuse headache, etc.) in this particular population. A careful medical history and general and neurological examinations and sometimes further investigations may be needed to rule out secondary headache syndromes. In pwMS, the headache could be an adverse effect of the disease-modifying therapies or a complication of pain medication overuse prescribed to relieve other causes of pain related to MS (neuropathic pain, mechanical pain, pain associated with spasticity, etc.). Migraine-type headache occurs in pwMS more frequently than in the general population. It can precede the disease onset, be associated with relapses, or appear during the MS course. A predominance of brainstem inflammatory lesions is described on magnetic resonance imaging (MRI) in MS patients with migraine. The relationship between both conditions remains unclear. Migraine and MS occur in the same demographic groups with similar background factors, including gender, hormonal status, and psychological features (anxiety, depression, stress). An early diagnosis and adequate treatment of migraine in MS patients are important to improve their quality of life. In this review, we focus on the relationship between MS and Migraine, discuss the differential diagnoses of migraine in pwMS, and describe its management in this particular context.

Immunologic aspects of migraine: A review of literature

Migraine headaches are highly prevalent, affecting 15% of the population. However, despite many studies to determine this disease's mechanism and efficient management, its pathophysiology has not been fully elucidated. There are suggested hypotheses about the possible mediating role of mast cells, immunoglobulin E, histamine, and cytokines in this disease. A higher incidence of this disease in allergic and asthma patients, reported by several studies, indicates the possible role of brain mast cells located around the brain vessels in this disease. The mast cells are more specifically within the dura and can affect the trigeminal nerve and cervical or sphenopalatine ganglion, triggering the secretion of substances that cause migraine. Neuropeptides such as calcitonin gene-related peptide (CGRP), neurokinin-A, neurotensin (NT), pituitary adenylate-cyclase-activating peptide (PACAP), and substance P (SP) trigger mast cells, and in response, they secrete pro-inflammatory and vasodilatory molecules such as interleukin-6 (IL-6) and vascular endothelial growth factor (VEGF) as a selective result of corticotropin-releasing hormone (CRH) secretion. This stress hormone contributes to migraine or intensifies it. Blocking these pathways using immunologic agents such as CGRP antibody, anti-CGRP receptor antibody, and interleukin-1 beta (IL-1β)/interleukin 1 receptor type 1 (IL-1R1) axis-related agents may be promising as potential prophylactic migraine treatments. This review is going to summarize the immunological aspects of migraine.

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.

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.

Headache in multiple sclerosis - pharmacological aspects

For decades, headache was not considered a typical symptom of multiple sclerosis (MS) and was construed as a "red flag" for important differential diagnoses such as cerebral vasculitis. Meanwhile, several studies have demonstrated an increased prevalence of headache in MS compared to the general population. This is due to the heterogeneity of headache genesis with frequent occurrence of both primary and secondary headaches in MS. On the one hand, MS and migraine are often comorbid. On the other hand, secondary headaches occur frequently, especially in the course of MS relapses. These are often migraine-like headaches caused by inflammation, which can improve as a result of MS-specific therapy. Headaches are particularly common in the early stages of chronic inflammatory CNS disease, where inflammatory activity is greatest. In addition, headache can also occur as a side effect of disease-modifying drugs (DMDs). Headache can occur with most DMDs and is most frequently described with interferon-beta therapy. The aim of this work is to present the prevalence of headache and describe the heterogeneity of possible causes of headache in MS. In addition, important therapeutic aspects in the treatment of MS patients in general will be presented as well as different approaches to the treatment of headache in MS depending on the etiological classification.

Migraine in Multiple Sclerosis Patients Affects Functional Connectivity of the Brain Circuitry Involved in Pain Processing

Migraine is particularly common in patients with multiple sclerosis (MS) and has been linked to the dysfunction of the brain circuitry modulating the peripheral nociceptive stimuli. Using MRI, we explored whether changes in the resting state-functional connectivity (RS-FC) may characterize the occurrence of migraine in patients with MS. The RS-FC characteristics in concerned brain regions were explored in 20 MS patients with migraine (MS+M) during the interictal phase, and compared with 19 MS patients without migraine (MS-M), which served as a control group. Functional differences were correlated to the frequency and severity of previous migraine attacks, and with the resulting impact on daily activities. In MS+M, the loss of periaqueductal gray matter (PAG) positive connectivity with the default mode network and the left posterior cranial pons was associated with an increase of migraine attacks frequency. In contrast, the loss of PAG negative connectivity with sensorimotor and visual network was linked to migraine symptom severity and related daily activities impact. Finally, a PAG negative connection was established with the prefrontal executive control network. Migraine in MS+M patients and its impact on daily activities, underlies RS-FC rearrangements between brain regions involved in pain perception and modulation.

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.

[Neuropathic pain syndromes in patients with multiple sclerosis]

Among the numerous pain syndromes (PS) of various localizations and types, observed in patients with multiple sclerosis (MS), the greatest attention of researchers is attracted by neuropathic PS. Neuropathic PS are often present already in the early stage of MS, significantly reduce the quality of life, hinder the social adaptation of patients, poorly respond to therapy. Central neuropathic PS, which pathogenesis is closely related with plaques in the central nervous system, are most common in patients with MS. Diagnostics of neuropathic PS in MS is based mainly on typical clinical symptoms; MRI and neurophysiological methods data are of secondary importance. This review focuses on modern concepts of three main neuropathic PS in MS: ongoing extremity pain, trigeminal neuralgia and Lhermitte's sign. Clinical symptoms of neuropathic PS, current ideas about their pathogenetic mechanisms, MRI and neurophysiological techniques data and the existing approaches to conservative therapy and surgical treatment based on randomized trials data are presented.

Intracranial nociception

Understanding intracranial nociceptive innervation is essential to understand the pathophysiology of headaches. Our knowledge about human intracranial nociception comes from sparse observations during neurosurgical procedures performed in awake patients, from human anatomical studies and from experimental studies in animals. In this article we review the anatomical and functional organization underlying nociceptive innervation. Intracranial nociception is mainly mediated by the trigeminal system, except in the posterior cranial fossa that is innervated by the first cervical roots. For decades, the dura mater, its vessels and major cerebral blood vessels were considered as the only intracranial pain-sensitive structures. Recent animal and human studies have suggested that smaller brain arteries and potentially pia mater might also be pain sensitive. Nociceptive neurons innervating intracranial blood vessels project via the ophthalmic division (V1) to the trigeminal ganglion and store several neurotransmitters including glutamate, substance P and calcitonin gene-related peptide (CGRP). The trigeminal ganglion, root and brainstem nuclei have a specific topographic and functional somatotopy. Progressive transition between the trigeminal spinal nucleus and the dorsal horn of the cervical spinal cord, and convergence of nociceptive inputs from the face, intracranial structures and the occipital area on the so-called "trigemino-cervical complex" may explain some headache features, relations between facial and occipital pain, and efficacy of occipital nerve stimulation in headache. The specific anatomic organization of the trigeminal system, from the primary-order neuron in the trigeminal ganglion, to the second-order neuron is the trigeminal nuclei, may explain a part of the various characteristics of headaches.

TRPM8 Channels: Advances in Structural Studies and Pharmacological Modulation

The transient receptor potential melastatin subtype 8 (TRPM8) is a cold sensor in humans, activated by low temperatures (>10, <28 °C), but also a polymodal ion channel, stimulated by voltage, pressure, cooling compounds (menthol, icilin), and hyperosmolarity. An increased number of experimental results indicate the implication of TRPM8 channels in cold thermal transduction and pain detection, transmission, and maintenance in different tissues and organs. These channels also have a repercussion on different kinds of life-threatening tumors and other pathologies, which include urinary and respiratory tract dysfunctions, dry eye disease, and obesity. This compendium firstly covers newly described papers on the expression of TRPM8 channels and their correlation with pathological states. An overview on the structural knowledge, after cryo-electron microscopy success in solving different TRPM8 structures, as well as some insights obtained from mutagenesis studies, will follow. Most recently described families of TRPM8 modulators are also covered, along with a section of molecules that have reached clinical trials. To finalize, authors provide an outline of the potential prospects in the TRPM8 field.

Migraine in multiple sclerosis and other chronic inflammatory diseases

Migraine is a very prevalent disease worldwide and is a major cause of disability. As known for a long time, migraine is associated with neurogenic inflammation. Epidemiological studies have shown that migraine is comorbid with several chronic inflammatory diseases, including multiple sclerosis (MS), chronic inflammatory rheumatic diseases (CIRDs) and inflammatory bowel diseases (IBDs). This brief narrative review highlights some recent data supporting a link between migraine and these three chronic inflammatory diseases. Studies found that migraine prevalence is approximately two-fold higher in these diseases compared to the general population. The causal link between migraine and these chronic inflammatory diseases has not been identified yet. Here, we suggest that systemic mediators (such as cytokines) and gut microbiome make migraine worse or add significant risks. Systemic inflammation biomarkers and gut microbiome modification are certainly avenues worth exploring.

Characteristics of pain in patients with pituitary adenomas: A cross-sectional study

BACKGROUND

This study determines the prevalence and particularities of headache and pain with neuropathic characteristics (NC) in a large French group of patients with pituitary adenoma (PA).

METHODS

Analysis of validated self-administered questionnaires, radiological characteristics and treatment strategies of PA was performed.

RESULTS

Of the 221 sent questionnaires, 146 could be used for statistical analysis, 50% of which were completed by women. Among responders, 58.9% had pain: 30.1% migraine, 15.7% pain with NC and 13.1% other types of pain. Migraine was more common in patients with PA than in the general population (30.1% vs. 21.3%, p = .010) and attacks received appropriate treatment for less than 20% of these patients. Furthermore, the prevalence of chronic migraine was much higher than in the general population (6.8% vs. 2.2%, p = .003). Neuropathic pain was also more frequent in PA patients than in the general population (15.8% vs. 6.9%, p < .001). Neuropathic pain was most often located in the extremities and was frequently described as an 'electric shock', 'numbness', or 'pins-and-needles'. Multivariate analyses linked migraine to younger age, anxiety, pain with NC, and a visible tumour on MRI, regardless of its invasiveness or secretory nature.

CONCLUSIONS

Migraine headaches and neuropathic pain are more frequent and disabling in PA patients than in the general population. Both types of pain are comorbid in PA patients and are poorly treated. Migraine is associated with the presence of a tumour. Thus, biological mechanisms of this relationship need to be characterized to design optimal treatments for these individuals.

SIGNIFICANCE

Migraine headaches and neuropathic pain are more common in PA patients than in the general population and are generally poorly treated. A systematic screening for migraine should be done by physicians in daily practice to provide adequate therapeutics.

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.

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.

[Headache in multiple sclerosis]

The relationship between headache and multiple sclerosis (MS) has been a matter of controversy for over 60 years. Headaches are still rated as a "red flag", indicating alternative diagnoses to MS, although in the last few years numerous studies have shown a frequent association between headache and MS. In recent studies on MS patients, a link was found between lower age/shorter disease duration of MS and frequent headaches. A study of 50 patients manifesting MS for the first time showed the highest headache prevalence in MS of 78% reported so far.Headaches can also be a possible side effect of most disease-modifying MS drugs. In many cases, however, the headache appears to be a symptom of MS in terms of secondary headache. This is also supported by pathophysiological implications, for example, by detecting B cell follicles in the meninges of MS patients.Migraine is the most common type of headache in MS. In some cases, this is a comorbidity of two diseases with many similarities, but headaches caused by inflammatory MS lesions also appear to be phenomenologically very similar to classic migraines; thus, distinguishing between them is often only successful with the help of thorough differential diagnostics (cerebrospinal fluid, MRI etc.).The task of future studies must be to specify the phenomenology of headache in MS even more precisely, in order to, to gain knowledge in, among others, patients with radiologically isolated syndrome, who often suffer from headache, because in these patients a considerable differential diagnostic and therapeutic uncertainty exists.

Pharmacological treatment of central neuropathic pain: consensus of the Brazilian Academy of Neurology

ABSTRACT Background: Central neuropathic pain (CNP) is often refractory to available therapeutic strategies and there are few evidence-based treatment options. Many patients with neuropathic pain are not diagnosed or treated properly. Thus, consensus-based recommendations, adapted to the available drugs in the country, are necessary to guide clinical decisions. Objective: To develop recommendations for the treatment of CNP in Brazil. Methods: Systematic review, meta-analysis, and specialists opinions considering efficacy, adverse events profile, cost, and drug availability in public health. Results: Forty-four studies on CNP treatment were found, 20 were included in the qualitative analysis, and 15 in the quantitative analysis. Medications were classified as first-, second-, and third-line treatment based on systematic review, meta-analysis, and expert opinion. As first-line treatment, gabapentin, duloxetine, and tricyclic antidepressants were included. As second-line, venlafaxine, pregabalin for CND secondary to spinal cord injury, lamotrigine for CNP after stroke, and, in association with first-line drugs, weak opioids, in particular tramadol. For refractory patients, strong opioids (methadone and oxycodone), cannabidiol/delta-9-tetrahydrocannabinol, were classified as third-line of treatment, in combination with first or second-line drugs and, for central nervous system (CNS) in multiple sclerosis, dronabinol. Conclusions: Studies that address the treatment of CNS are scarce and heterogeneous, and a significant part of the recommendations is based on experts opinions. The CNP approach must be individualized, taking into account the availability of medication, the profile of adverse effects, including addiction risk, and patients' comorbidities.

Prevalence of Migraine and Neuropathic Pain in Rheumatic Diseases

To investigate the physiopathology of pain in chronic inflammatory rheumatic diseases (CIRDs), we assessed the prevalence of migraine and neuropathic pain in 499 patients with CIRDs. We studied 238 patients with rheumatoid arthritis, 188 with spondyloarthritis (SpA), 72 with psoriatic arthritis (PsA), and 1 unclassified. Migraine was diagnosed according to IHS migraine diagnostic criteria. Neuropathic pain was diagnosed when patients scored at least 3 on the DN4 questionnaire. Participants completed a validated self-assessment questionnaire. Migraine prevalence was 34% (165/484), and it was highest in PsA. Risk factors for migraine were a high level of anxiety, female sex, young age, and TNF-alpha inhibitor treatment (OR = 1.90 (1.13–3.25)). Besides, high disease activity was a risk factor in SpA. Blood CRP level was not significantly associated with migraine. Of 493 patients with CIRDs, 21.5% had chronic pain with neuropathic characteristics. Compared to the French general population, these patients had significantly higher prevalences of migraine (two-fold) and neuropathic pain (three-fold). This study showed that migraine and neuropathic pain frequently occurred in patients with rheumatic diseases. Therefore, upon reporting residual pain, these patients should be checked for the presence of migraine or neuropathic pain, despite adequate clinical control of rheumatic disease.

Characterization of pain syndromes in patients with neuromyelitis optica

BACKGROUND

Pain is common and refractory in spinal cord injury (SCI). Currently, most studies evaluated pain in male-predominant traumatic-SCI. Also, concomitant secondary pain syndromes and its temporal evolution were seldom reported.

METHODS

We aimed to prospectively describe the main and secondary pain and its associated factors in inflammatory-SCI evaluating neuromyelitis optica (NMO) patients. In-remission NMO patients underwent neurological, imaging and autoantibody evaluations. Questionnaires detailing main and secondary pains, functional state, mood, catastrophizing, quality of life (QoL) and "non-motor symptoms" were used at two time points.

RESULTS

Pain was present in 53 (73.6%) of the 72 patients included. At-level neuropathic pain was the most common main pain syndrome, affecting 32 subjects (60.4% of those with pain). Over 70% (n = 38) of this cohort reported two pain syndromes. Those without pain were significantly younger (26.1 ± 12.7 y.o. in those without pain and 40.1 ± 12.5, 37.2 ± 11.4 y.o. in those whose main pain was neuropathic and non-neuropathic, respectively, p = .001), and no differences in the inflammatory status were observed between groups. On follow-up, one-fifth (n = 11) had a different main pain syndrome from the first visit. Pain impacted QoL as much as disability and motor strength.

CONCLUSION

Pain is a prevalent and disabling non-motor symptom in NMO-SCI. Most patients experience more than one pain syndrome which can change in time even in the absence of clinical relapse. Age of the inflammatory-SCI was a major determinant of pain. Acknowledging temporal changes and multiplicity of pain syndromes in NMO-SCI may give insights into more precise designs of clinical trials and general management of pain in SCI.

SIGNIFICANCE

In this longitudinal study with NMO-related SCI, pain affected almost three-quarters of patients with NMO. Over 70% have more than one pain syndrome and at-level neuropathic pain is the most common type of pain syndrome. Patients without pain were significantly younger but had the same burden of inflammatory lesions than those with pain. During follow-up, up to one fifth of patients presented with changes in the main pain syndromes, which can occur even in the absence of clinical activity of the inflammatory disease. In this cohort, Pain affected quality of life as much as disability or motor strength.

Non-invasively triggered spreading depolarizations induce a rapid pro-inflammatory response in cerebral cortex

Cortical spreading depolarization (CSD) induces pro-inflammatory gene expression in brain tissue. However, previous studies assessing the relationship between CSD and inflammation have used invasive methods that directly trigger inflammation. To eliminate the injury confounder, we induced CSDs non-invasively through intact skull using optogenetics in Thy1-channelrhodopsin-2 transgenic mice. We corroborated our findings by minimally invasive KCl-induced CSDs through thinned skull. Six CSDs induced over 1 h dramatically increased cortical interleukin-1β (IL-1β), chemokine (C-C motif) ligand 2 (CCL2), and tumor necrosis factor-α (TNF-α) mRNA expression peaking around 1, 2 and 4 h, respectively. Interleukin-6 (IL-6) and intercellular adhesion molecule-1 (ICAM-1) were only modestly elevated. A single CSD also increased IL-1β, CCL2, and TNF-α, and revealed an ultra-early IL-1β response within 10 min. The response was blunted in IL-1 receptor-1 knockout mice, implicating IL-1β as an upstream mediator, and suppressed by dexamethasone, but not ibuprofen. CSD did not alter systemic inflammatory indices. In summary, this is the first report of pro-inflammatory gene expression after non-invasively induced CSDs. Altogether, our data provide novel insights into the role of CSD-induced neuroinflammation in migraine headache pathogenesis and have implications for the inflammatory processes in acute brain injury where numerous CSDs occur for days.

Central Neuropathic Pain and Profiles of Quantitative Electroencephalography in Multiple Sclerosis Patients

Pain has a significant impact on the quality of life of patients with multiple sclerosis (MS). However, the neurophysiological mechanisms of central neuropathic pain in a MS course are not known. We hypothesized that changes in power spectral density (PSD) that take place in the electroencephalography (EEG) of MS patients with and without the central neuropathic pain (CNP) would differ. The study aimed to assess the features of quantitative EEG using the PSD indicator along with peak frequencies in the standard frequency bands in MS patients with and without CNP. We have analyzed the quantitative spectral content of the EEG at a resting state in 12 MS patients with CNP, 12 MS patients without CNP, and 12 gender- and age-matched healthy controls using fast Fourier transformation. Based on the ANOVA, at the group level, the theta band absolute and relative PSD showed an increase, whereas alpha band relative PSD showed a decrease in MS patients both with and without CNP. However, only in MS with CNP group, the absolute and relative PSD in the beta1 and beta2 bands increased and exceeded that in patients without pain. Only MS patients with CNP demonstrated the significantly increased absolute PSD for the theta, beta1, and beta2 frequency bands in most regions of interest. In the theta band, MS patients with CNP displayed the increase in absolute spectral power for the mid-temporal derivation of the right hemisphere and the increase in relative spectral power for the prefrontal derivation of this hemisphere. In the beta1 band, the increase in absolute spectral power was observed for the three temporal derivations of the right hemisphere, whereas in the beta2 band, for the occipital, parietal, and temporal lobes of both hemispheres. In the alpha band, only a relative spectral power decrease was revealed for the occipital lobes of both hemispheres and parietal lobe of the right hemisphere. In MS patients with CNP, the frequencies of the dominant spectral power (peak frequencies) in the high-frequency beta band were higher than in the healthy control in posterior areas of the left hemisphere. Data could represent central nervous system alterations related to central neuropathic pain in MS patients that lead to the disturbances in cortical communication.

Whole-body reversible neuropathic pain associated with right parieto-temporal operculum single inflammatory lesion in a patient with multiple sclerosis: A case report

BACKGROUND

The posterior insula and the medial parietal operculum (PIMO) are part of the pain network. Pain can be induced by direct stimulation of the PIMO, but the clinical consequence of lesions in this brain area is not well known.

CASE REPORT

We report the case of a patient with multiple sclerosis who presented a relapse characterized by isolated widespread neuropathic pain. The MRI displayed a single new inflammatory lesion in the juxta cortical white matter of the opercular region. This lesion was extended to the parietal operculum and was associated with the pain syndrome. The patient was treated with high-dose intravenous methylprednisolone, and the pain disappeared progressively. Diffusion-tensor MRI showed that some of the fibres passing through the lesion ended in the PIMO.

CONCLUSION

Based on diffusion-tensor MRI we hypothesize that the partial disconnection from afference to the PIMO can lead to widespread neuropathic pain.

SIGNIFICANCE

Most of the data concerning the functional role of the PIMO come from stereoelectroencephalography in presurgical evaluation of epilepsy, or from functional imaging (PET or fMRI). There is, however, very few data on the consequences of the lesion of the PIMO. Here, we report the first case of a transient widespread pain syndrome associated to a single, small and reversible inflammatory lesion of the PIMO. Thus, this case highlights the key role of the PIMO in spatial perception of pain.

Headache in the course of multiple sclerosis: a prospective study

Multiple sclerosis (MS) is the most common immune-mediated inflammatory disease of the central nervous system (CNS). Early diagnosis and treatment is important to prevent progression of disability in the course of the chronic disease. Therefore, correct and fast identification of early symptoms is vital. Headache is generally not recognized as an early symptom of MS, although numerous studies could show a high prevalence of headache in MS patients. The most common misdiagnosis is migraine. The aim of this study is to investigate the prevalence as well as the phenomenology of headache in MS especially with regard to the progression of the disease. In a prospective, multicenter study, we unbiasedly recruited 150 patients with manifest MS based on the criteria of McDonald. 50 patients at the timepoint of initial diagnosis and 100 of them with a long-term course of the disease were included. Based on a semi-structured interview, we evaluated the occurrence of headache over the last 4 weeks as well as case history, clinical-neurological investigation and questionnaires about depression, fatigue, and quality of life. Prevalence of headache in all patients was 67%. Patients at the timepoint of symptom manifestation of MS showed the highest prevalence of headache that was ever been recorded of 78%. In general, patients with headache were younger, had a shorter duration of the disease, and were less physically affected. We noticed frequent occurrence of migraine and migraine-like headache. In the course of the disease, patients without disease-modifying drug (DMD) complained more frequently headaches than patients with any kind of therapy. Headache is an important early symptom of MS. This could be shown especially among 78% of patients with clinically isolated syndrome (CIS). Therefore, young people with frequent headache should undergo MRI of the head and in the case of abnormal findings a consecutive detailed differential diagnosis. This could reduce the latency until final diagnosis of MS, which is in general much too long. That way these patients could get the earliest possible treatment, which is important to stop the progression of the disease.

Identifying neuropathic pain in patients with multiple sclerosis: a cross-sectional multicenter study using highly specific criteria

BACKGROUND

Pain is a common and heterogeneous complication of multiple sclerosis (MS). In this multicenter, cross sectional study, we aimed at investigating the prevalence of pain in MS using highly specific criteria for distinguishing the different types of pain.

MATERIALS AND METHODS

After a structured interview, in patients with pain, clinical examination and DN4 questionnaire were used for distinguishing neuropathic and nociceptive pain. In subjects with neuropathic pain, the Neuropathic Pain Symptom Inventory was used for differentiating neuropathic pain symptoms.

RESULTS

We enrolled 1249 participants (832 F, 417 M, mean age 33.9 years, mean disease duration 8 years, mean EDSS 3.2); based on clinical evaluation and DN4 score 429 patients (34.34%) were classified with pain (470 pain syndromes): 286 nociceptive pain syndromes and 184 neuropathic pain syndromes. Multivariate analysis showed that pain was associated with age, gender and disease severity and that neuropathic pain was distinctly associated with EDSS.

CONCLUSIONS

Our study, providing definite information on the prevalence, characteristics and variables associated with neuropathic pain due to MS, shows that a more severe disease course is associated with a higher risk of neuropathic pain. Our findings might, therefore, provide a basis for improving the clinical management of this common MS complication.

What role does multiple sclerosis play in the development of untreatable painful conditions?

Clinical data outline the high incidence of pain syndromes in patients with multiple sclerosis, with a significant prevalence of craniofacial manifestations, including trigeminal neuralgia and migraine, which are very difficult to be managed pharmacologically. The common explanation of a localization of demyelinating plaques in areas devoted to pain modulation and integration as a trigger for pain development seems now partially unsatisfactory, since pain is often manifested well before the clinical signs of the pathology and its severity does not correlate with disease progression. This review focuses on additional mechanisms which could be at the basis of pain development in multiple sclerosis, whose identification will help identifying new targets to design more effective analgesic strategies.

Botulinum Toxin Treatment in Multiple Sclerosis-a Review

Purpose of review The purpose of this review is to provide updated information on the role of botulinum neurotoxin (BoNT) therapy in multiple sclerosis (MS). This review aims to answer which symptoms of multiple sclerosis may be amenable to BoNT therapy. Recent findings We searched the literature on the efficacy of BoNTs for treatment of MS symptoms up to April 1st 2017 via the Yale University Library's search engine including but not limited to Pub Med and Ovis SP. The level of efficacy was defined according to the assessment's criteria set forth by the Subcommittee on Guideline Development of the American Academy of Neurology. Significant efficacy was found for two indications based on the available blinded studies (class I and II) and has been suggested for several others through open-label clinical trials. Summary There is level A evidence (effective- two or more class I) that injection of BoNT-A into the bladder's detrusor muscle improves MS-related neurogenic detrusor overactivity (NDO) and MS-related overactive (OA) bladder. There is level B evidence (probably effective- two class II studies) for utility of intramuscular BoNT-A injections for spasticity of multiple sclerosis. Emerging data based on retrospective class IV studies demonstrates that intramuscular injection of BoNTs may help other symptoms of MS such as focal tonic spasms, focal myokymia, spastic dysphagia, and double vision in internuclear ophthalmoplegia. There is no data on MS-related trigeminal neuralgia and sialorrhea, two conditions which have been shown to respond to BoNT therapy in non-MS population.

Multiple Sclerosis-Related Pain Syndromes: An Imaging Update

Pain in multiple sclerosis (MS) is a common manifestation, made up of complex phenomenon involving intricate neurophysiological processing at central levels of the pain pathway. Our understanding of the clinical and neurophysiological mechanisms of central/neuropathic pain related to MS continues to improve with improved imaging techniques but remains a challenging area of research. The advancements in imaging techniques for lesion evaluation of the various neuroanatomic structures have improved our detection, diagnosis, and understanding of MS pain and help validate subjective symptoms. This article will discuss the updated criteria of MS neuropathic pain and critically review some of the latest research into imaging correlations of MS pain syndromes. And discuss how advanced MRI imaging techniques (such as functional magnetic resonance imaging [fMRI], 3D imaging, fluid attenuated inversion recovery [FLAIR*], and diffusion tensor imaging [DTI]) have detailed neuropathic pain with a focus on migraines and trigeminal neuralgias and will highlight some of the ongoing limitations, variabilities, and deficiencies.

Increased contrast enhancing lesion activity in relapsing-remitting multiple sclerosis migraine patients

Background and objectives

While the literature supports the idea that multiple sclerosis (MS) and migraine are related, the exact mechanism(s) of this association is not well understood. Observations of increased contrast enhancing (CE) lesion activity in individual MS patients suffering from migraine prompted us to determine a relationship between migraine and MRI outcomes in a large cohort of MS patients.

Methods

We included 509 MS and 64 clinically isolated syndrome (CIS) patients and 251 age- and sex-matched healthy individuals (HIs) who obtained 3 T MRI and were assessed for history of migraine. Number and volume of T2, T1 and CE lesions and brain volume measures were determined. The MRI findings were analyzed adjusting for key covariates and correcting for multiple comparisons.

Results

More MS (22.2%) and CIS (17.2%) patients had migraine, compared to HIs (14.6%, p = 0.067). More MS patients with migraine presented with CE lesions compared to those without (35.4% vs. 23.7%, p = 0.013). MS migraine patients had significantly increased number (p = 0.019) and volume (p = 0.022) of CE lesions compared to those without. In the regression analysis, MS migraine patients had an increased number of CE lesions (B = 1.242, p = 0.001), specifically those with relapsing–remitting disease course (B = 1.377, p = 0.001). No significant association of other MRI measures and migraine was found in MS and CIS patients or in HIs.

Conclusions

Our findings suggest an increased inflammatory pathobiology in MS patients with migraine headaches requiring possibly more frequent MRIs and also more efficient anti-inflammatory treatment.

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We examined 509 MS and 64 CIS patients and 251 healthy individuals.

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Subjects were assessed with 3 T MRI and for history of migraine.

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More MS and CIS patients had migraine, compared to healthy controls.

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More MS migraine patients presented with enhancing brain lesions compared to those without.

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MS migraine patients had an increased number and volume of enhancing lesions.

The Prevalence of Pain in Adults with Multiple Sclerosis: A Multicenter Cross-Sectional Survey

OBJECTIVE

Examination of prevalence, intensity and associations of pain in persons with multiple sclerosis (MS).

DESIGN

Multicenter, international cross-sectional survey.

SETTING

Patients were recruited from seven MS centers: in Serbia (Clinic of Neurology, Clinical Center of Serbia, Belgrade; Clinic of Neurology, Military Medical Academy, Belgrade; Clinic of Neurology, Clinical Center Kragujevac; Clinic of Neurology, Clinical Center Nis; Department of Neurology, General Hospital-Uzice), in Republic of Srpska-Bosnia and Herzegovina (Clinic of Neurology, Clinical Center Banja Luka) and in Croatia (University Department of Neurology, Sestre Milosrdnice University Hospital Center, Zagreb).

SUBJECTS

Six hundred and fifty consecutive MS patients diagnosed according to the Revised McDonald criteria (2005), from the aforementioned centers, over the period of 6 months.

METHODS

A semistructured questionnaire was administered during a face-to-face interview with neurologists who also performed Expanded Disability Status Scale (EDSS), the Hamilton Rating Scale for Depression (HDRS) and Hamilton Rating Scale for Anxiety (HARS). To recognize predictive factors for the presence of pain, the linear regression analysis was used.

RESULTS

Lifetime prevalence of pain was 66.5% (point prevalence = 44.3%). The prevalence of the comorbidity of pain and depression was 29.1%. Older age (P < 0.001), primary-progressive MS (P = 0.034), higher EDSS score (P = 0.008), higher scores of HDRS (P < 0.001), and HARS (P < 0.001) were significantly associated with pain. Finally, in our multivariate linear regression analysis, anxiety (P < 0.001) was the independent predictor of pain.

CONCLUSIONS

We confirmed high prevalence of pain, affecting approximately more than half of patients during the course of MS. Pain in MS is associated with disability, depression and, especially with anxiety, which has significant implications for treatment.

Towards a better understanding of MS pain: a systematic review of potentially modifiable psychosocial factors

OBJECTIVE

Pain is a common symptom of Multiple Sclerosis (MS). Biomedical treatments achieve only modest reductions in pain severity suggesting that this approach may be too narrow. The aim of this systematic review was to assess evidence for associations between modifiable psychosocial factors and MS pain severity and pain interference and use this evidence to develop a preliminary biopsychosocial model of MS pain.

METHODS

Empirical studies of pain in MS utilising standardised pain severity and pain interference measures were included. Online databases (Cochrane, PsychInfo, EMBASE, CINAHL, Medline, Web of Science and World Cat) and reference sections of included articles were searched, and corresponding authors contacted to identify unpublished studies. Information about design, sample size, MS type, time since diagnosis, psychosocial and pain measures and key findings were extracted. Thirty-one studies were assessed for quality and a narrative synthesis was conducted.

RESULTS

Similar to primary chronic pain, most studies reported small to medium associations between several psychosocial factors and pain severity and interference. Pain catastrophizing showed consistently strong associations with pain interference. Preliminary findings revealed a strong correlation between pain acceptance and pain interference. However, fear-avoidance appeared less important in MS, and other forms of behavioural avoidance were not explored.

CONCLUSIONS

A preliminary model of MS pain outlining specific psychosocial factors is presented with a conceptual formulation from both traditional, and contextual, cognitive-behavioural perspectives. Pain catastrophizing, acceptance, and endurance, as opposed to fear avoidance, responses are highlighted as potentially important treatment targets in MS, and directions for future research are outlined.