Site matters: Central neuropathic pain characteristics and somatosensory findings after brain and spinal cord lesions.

BACKGROUND: It is unknown if different etiologies or lesion topographies influence central neuropathic pain (CNP) clinical manifestation. METHODS: We explored the symptom-somatosensory profile relationships in CNP patients with different types of lesions to the central nervous system to gain insight into CNP mechanisms. We compared the CNP profile through pain descriptors, standardized bedside examination, and quantitative sensory test in two different etiologies with segregated lesion locations: the brain, central poststroke pain (CPSP, n = 39), and the spinal cord central pain due to spinal cord injury (CPSCI, n = 40) in neuromyelitis optica. RESULTS: Results are expressed as median (25th to 75th percentiles). CPSP presented higher evoked and paroxysmal pain scores compared to CPSCI (p < 0.001), and lower cold thermal limen (5.6°C [0.0-12.9]) compared to CPSCI (20.0°C [4.2-22.9]; p = 0.004). CPSCI also had higher mechanical pain thresholds (784.5 mN [255.0-1078.0]) compared to CPSP (235.2 mN [81.4-1078.0], p = 0.006) and higher mechanical detection threshold compared to control areas (2.7 [1.5-6.2] vs. 1.0 [1.0-3.3], p = 0.007). Evoked pain scores negatively correlated with mechanical pain thresholds (r = -0.38, p < 0.001) and wind-up ratio (r = -0.57, p < 0.001). CONCLUSIONS: CNP of different etiologies may present different pain descriptors and somatosensory profiles, which is likely due to injury site differences within the neuroaxis. This information may help better design phenotype mechanism correlations and impact trial designs for the main etiologies of CNP, namely stroke and spinal cord lesions. This study provides evidence that topography may influence pain symptoms and sensory profile. The findings suggest that CNP mechanisms might vary according to pain etiology or lesion topography, impacting future mechanism-based treatment choices.

Corticomotor excitability is altered in central neuropathic pain compared with non-neuropathic pain or pain-free patients.

OBJECTIVES: Central neuropathic pain (CNP) is associated with altered corticomotor excitability (CE), which can potentially provide insights into its mechanisms. The objective of this study is to describe the CE changes that are specifically related to CNP. METHODS: We evaluated CNP associated with brain injury after stroke or spinal cord injury (SCI) due to neuromyelitis optica through a battery of CE measurements and comprehensive pain, neurological, functional, and quality of life assessments. CNP was compared to two groups of patients with the same disease: i. with non-neuropathic pain and ii. without chronic pain, matched by sex and lesion location. RESULTS: We included 163 patients (stroke=93; SCI=70: 74 had CNP, 43 had non-neuropathic pain, and 46 were pain-free). Stroke patients with CNP had lower motor evoked potential (MEP) in both affected and unaffected hemispheres compared to non- neuropathic pain and no-pain patients. Patients with CNP had lower amplitudes of MEPs (366 µV ±464 µV) than non-neuropathic (478 ±489) and no-pain (765 µV ± 880 µV) patients, p < 0.001. Short-interval intracortical inhibition (SICI) was defective (less inhibited) in patients with CNP (2.6±11.6) compared to no-pain (0.8±0.7), p = 0.021. MEPs negatively correlated with mechanical and cold-induced allodynia. Furthermore, classifying patients' results according to normative data revealed that at least 75% of patients had abnormalities in some CE parameters and confirmed MEP findings based on group analyses. DISCUSSION: CNP is associated with decreased MEPs and SICI compared to non-neuropathic pain and no-pain patients. Corticomotor excitability changes may be helpful as neurophysiological markers of the development and persistence of pain after CNS injury, as they are likely to provide insights into global CE plasticity changes occurring after CNS lesions associated with CNP.

Parkinson's Disease-related Pains are Not Equal: Clinical, Somatosensory and Cortical Excitability Findings in Individuals With Nociceptive Pain.

Chronic pain is a frequent and burdensome nonmotor symptom of Parkinson's disease (PD). PD-related chronic pain can be classified as nociceptive, neuropathic, or nociplastic, the former being the most frequent subtype. However, differences in neurophysiologic profiles between these pain subtypes, and their potential prognostic and therapeutic implications have not been explored yet. This is a cross-sectional study on patients with PD (PwP)-related chronic pain (ie, started with or was aggravated by PD). Subjects were assessed for clinical and pain characteristics through questionnaires and underwent quantitative sensory tests and motor corticospinal excitability (CE) evaluations. Data were then compared between individuals with nociceptive and non-nociceptive (ie, neuropathic or nociplastic) pains. Thirty-five patients were included (51.4% male, 55.7 ± 11.0 years old), 20 of which had nociceptive pain. Patients with nociceptive PD-related pain had lower warm detection threshold (WDT, 33.34 ± 1.39 vs 34.34 ± 1.72, P = .019) and mechanical detection threshold (MDT, 2.55 ± 1.54 vs 3.86 ± .97, P = .007) compared to those with non-nociceptive pains. They also presented a higher proportion of low rest motor threshold values than the non-nociceptive pain ones (64.7% vs 26.6%, P = .048). In non-nociceptive pain patients, there was a negative correlation between WDT and non-motor symptoms scores (r = -.612, P = .045) and a positive correlation between MDT and average pain intensity (r = .629, P = .038), along with neuropathic pain symptom scores (r = .604, P = .049). It is possible to conclude that PD-related chronic pain subtypes have distinctive somatosensory and CE profiles. These preliminary data may help better frame previous contradictory findings in PwP and may have implications for future trial designs aiming at developing individually-tailored therapies. PERSPECTIVE: This work showed that PwP-related nociceptive chronic pain may have distinctive somatosensory and CE profiles than those with non-nociceptive pain subtypes. These data may help shed light on previous contradictory findings in PwP and guide future trials aiming at developing individually-tailored management strategies.

Dissecting central post-stroke pain: a controlled symptom-psychophysical characterization.

Central post-stroke pain affects up to 12% of stroke survivors and is notoriously refractory to treatment. However, stroke patients often suffer from other types of pain of non-neuropathic nature (musculoskeletal, inflammatory, complex regional) and no head-to-head comparison of their respective clinical and somatosensory profiles has been performed so far. We compared 39 patients with definite central neuropathic post-stroke pain with two matched control groups: 32 patients with exclusively non-neuropathic pain developed after stroke and 31 stroke patients not complaining of pain. Patients underwent deep phenotyping via a comprehensive assessment including clinical exam, questionnaires and quantitative sensory testing to dissect central post-stroke pain from chronic pain in general and stroke. While central post-stroke pain was mostly located in the face and limbs, non-neuropathic pain was predominantly axial and located in neck, shoulders and knees (P < 0.05). Neuropathic Pain Symptom Inventory clusters burning (82.1%, n = 32, P < 0.001), tingling (66.7%, n = 26, P < 0.001) and evoked by cold (64.1%, n = 25, P < 0.001) occurred more frequently in central post-stroke pain. Hyperpathia, thermal and mechanical allodynia also occurred more commonly in this group (P < 0.001), which also presented higher levels of deafferentation (P < 0.012) with more asymmetric cold and warm detection thresholds compared with controls. In particular, cold hypoesthesia (considered when the threshold of the affected side was <41% of the contralateral threshold) odds ratio (OR) was 12 (95% CI: 3.8-41.6) for neuropathic pain. Additionally, cold detection threshold/warm detection threshold ratio correlated with the presence of neuropathic pain (ρ = -0.4, P < 0.001). Correlations were found between specific neuropathic pain symptom clusters and quantitative sensory testing: paroxysmal pain with cold (ρ = -0.4; P = 0.008) and heat pain thresholds (ρ = 0.5; P = 0.003), burning pain with mechanical detection (ρ = -0.4; P = 0.015) and mechanical pain thresholds (ρ = -0.4, P < 0.013), evoked pain with mechanical pain threshold (ρ = -0.3; P = 0.047). Logistic regression showed that the combination of cold hypoesthesia on quantitative sensory testing, the Neuropathic Pain Symptom Inventory, and the allodynia intensity on bedside examination explained 77% of the occurrence of neuropathic pain. These findings provide insights into the clinical-psychophysics relationships in central post-stroke pain and may assist more precise distinction of neuropathic from non-neuropathic post-stroke pain in clinical practice and in future trials.

Cannabinoids in Neurology - Position paper from Scientific Departments from Brazilian Academy of Neurology.

Cannabinoids comprehend endocannabinoids, phytocannabinoids, and synthetic cannabinoids, with actions both in the central and peripherical nervous systems. A considerable amount of publications have been made in recent years, although cannabis has been known for over a thousand years. Scientific Departments from the Brazilian Academy of Neurology described evidence for medical use in their areas. Literature is constantly changing, and possible new evidence can emerge in the next days or months. Prescription of these substances must be discussed with patients and their families, with knowledge about adverse events and their efficacy.

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

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.

Insular and anterior cingulate cortex deep stimulation for central neuropathic pain: Disassembling the percept of pain.

OBJECTIVE: To compare the analgesic effects of stimulation of the anterior cingulate cortex (ACC) or the posterior superior insula (PSI) against sham deep (d) repetitive (r) transcranial magnetic stimulation (TMS) in patients with central neuropathic pain (CNP) after stroke or spinal cord injury in a randomized, double-blinded, sham-controlled, 3-arm parallel study. METHODS: Participants were randomly allocated into the active PSI-rTMS, ACC-rTMS, sham-PSI-rTMS, or sham-ACC-rTMS arms. Stimulations were performed for 12 weeks, and a comprehensive clinical and pain assessment, psychophysics, and cortical excitability measurements were performed at baseline and during treatment. The main outcome of the study was pain intensity (numeric rating scale [NRS]) after the last stimulation session. RESULTS: Ninety-eight patients (age 55.02 ± 12.13 years) completed the study. NRS score was not significantly different between groups at the end of the study. Active rTMS treatments had no significant effects on pain interference with daily activities, pain dimensions, neuropathic pain symptoms, mood, medication use, cortical excitability measurements, or quality of life. Heat pain threshold was significantly increased after treatment in the PSI-dTMS group from baseline (1.58, 95% confidence interval [CI] 0.09-3.06]) compared to sham-dTMS (-1.02, 95% CI -2.10 to 0.04, p = 0.014), and ACC-dTMS caused a significant decrease in anxiety scores (-2.96, 95% CI -4.1 to -1.7]) compared to sham-dTMS (-0.78, 95% CI -1.9 to 0.3; p = 0.018). CONCLUSIONS: ACC- and PSI-dTMS were not different from sham-dTMS for pain relief in CNP despite a significant antinociceptive effect after insular stimulation and anxiolytic effects of ACC-dTMS. These results showed that the different dimensions of pain can be modulated in humans noninvasively by directly stimulating deeper SNC cortical structures without necessarily affecting clinical pain per se. CLINICALTRIALSGOV IDENTIFIER: NCT01932905.

Cannabinoids in Neurology - Position paper from Scientific Departments from Brazilian Academy of Neurology / Canabinoides em Neurologia - Artigo de posicionamento dos Departamentos Científicos da Academia Brasileira de Neurologia

ABSTRACT Cannabinoids comprehend endocannabinoids, phytocannabinoids, and synthetic cannabinoids, with actions both in the central and peripherical nervous systems. A considerable amount of publications have been made in recent years, although cannabis has been known for over a thousand years. Scientific Departments from the Brazilian Academy of Neurology described evidence for medical use in their areas. Literature is constantly changing, and possible new evidence can emerge in the next days or months. Prescription of these substances must be discussed with patients and their families, with knowledge about adverse events and their efficacy.

RESUMO Os canabinoides compreendem os endocanabinoides, fitocanabinoides e os canabinoides sintéticos e desempenham ações no sistema nervoso central e periférico. Uma quantidade enorme de publicações tem sido lançada nos últimos anos, embora a cannabis seja conhecida por milênios. Os Departamentos Científicos da Academia Brasileira de Neurologia descreveram as evidências do uso médico em suas áreas. A literatura está em constantes mudanças e possíveis novas evidências podem surgir nos próximos dias ou meses. A prescrição dessas substâncias deve ser discutida com os pacientes e suas famílias, com conhecimento sobre eventos adversos e sua eficácia.

Pharmacological treatment of central neuropathic pain: consensus of the Brazilian Academy of Neurology / Tratamento farmacológico da dor neuropática central: consenso da Academia Brasileira de Neurologia

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.

RESUMO Introdução: A dor neuropática central (DNC) é frequentemente refratária às estratégias terapêuticas disponíveis e há poucas opções de tratamento baseado em evidência. Muitos pacientes com dor neuropática não são diagnosticados ou tratados adequadamente. Desse modo, recomendações baseadas em consenso, adaptadas à disponibilidade de medicamentos no país, são necessárias para guiar decisões clínicas. Objetivo: Desenvolver recomendações para o tratamento da DNC no Brasil. Métodos: Revisão sistemática, metanálise e discussão dos resultados entre especialistas e pesquisadores da área, considerando eficácia, perfil de eventos adversos, custo e disponibilidade do fármaco na saúde pública. Resultados: Foram encontrados 44 estudos sobre tratamento da DNC, dos quais 20 foram incluídos na análise qualitativa e 15, na quantitativa. Classificaram-se as medicações em primeira, segunda e terceira linhas de tratamento, baseando-se em revisão sistemática, meta-análise e opinião de especialistas. Como primeira linha, foram incluídos gabapentina, duloxetina e antidepressivos tricíclicos. Como segunda, venlafaxina, pregabalina para DNC secundária à lesão medular, lamotrigina para DNC pós-acidente vascular cerebral e, em associação aos fármacos de primeira linha, opioides fracos, em particular tramadol. Para os pacientes refratários, opioides fortes (metadona e oxicodona) e canabidiol/delta-9-tetrahidrocanabinol foram classificados como terceira linha de tratamento, em associação com drogas de primeira ou segunda linha, e, para DNC na esclerose múltipla, dronabinol. Conclusões: Os estudos que abordam o tratamento da DNC são escassos e heterogêneos, e parte significativa das recomendações é baseada em opiniões de especialistas. A abordagem da DNC deve ser individualizada, levando em conta a disponibilidade de medicação, o perfil de efeitos adversos, incluindo risco de dependência e as comorbidades do paciente.

Family income and survival in Brazilian Peritoneal Dialysis Multicenter Study Patients (BRAZPD): time to revisit a myth?

BACKGROUND AND OBJECTIVES: Although low socioeconomic status has been considered a contraindication to peritoneal dialysis (PD), no published data clearly link it to poor outcomes. The goal of this study was assessing the effect of income on survival in the Brazilian Peritoneal Dialysis Multicenter STUDY. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Incident PD patients enrolled in this prospective cohort from December 2004 to October 2007 were divided according to monthly family income. The median age was 59 years, 54% were women, 60% Caucasians, 41% diabetics, and 24% had cardiovascular disease. Most of them were in continuous ambulatory PD, had not received predialysis care, had <4 school years, and had a family income of <5 minimum wage (80%). Survival analysis was performed using the Kaplan-Meier method and the Cox proportional hazards model adjusting the results for age, gender, educational status, predialysis care, first therapy, PD modality, calendar year, and comorbidities. RESULTS: There were no differences in technique (log rank test χ² = 4.36) and patient (log rank test χ² = 2.92) survival between the groups. In the multivariate analysis, low family income remained not associated either to worse technique survival (hazard ratio [HR] = 1.29; 95% confidence interval [CI] = 0.91 to 1.84) or to patient survival (HR = 1.40; 95% CI = 0.99 to 1.99). CONCLUSIONS: According to these results, economic status is not independently associated with outcomes in this large cohort and should not be considered a barrier for PD indication.

Aspartate aminotransferase-to-platelet ratio index for fibrosis and cirrhosis prediction in chronic hepatitis C patients.

In chronic hepatitis C (CHC), liver biopsy is the gold standard method for assessing liver histology, however it is invasive and can have complications. Non-invasive markers have been proposed and aspartate aminotransferase (AST)-to-platelet ratio index (APRI) has been shown as an easy and inexpensive marker of liver fibrosis. This study evaluated the diagnostic performance of APRI for significant fibrosis and cirrhosis prediction in CHC patients. This study included treatment-naive CHC patients who had undergone liver biopsy from January 2000 to August 2006. All histological slides were reviewed according to the METAVIR system. APRI was calculated based on laboratory results performed within four months from the biopsy. Twenty-eight (56%) patients had significant fibrosis (F2-F4) and 13 (26%) had cirrhosis (F4). The area under ROC curves of APRI for predicting significant fibrosis and cirrhosis were 0.92 (0.83-1.00) and 0.92 (0.85-1.00), respectively. Using cut-off values recommended by prior studies, significant fibrosis could be identified, in accordance with liver biopsy, in 44% and cirrhosis in 66% of patients. APRI could identify significant fibrosis and cirrhosis at a high degree of accuracy in studied patients.

Aspartate aminotransferase-to-platelet ratio index for fibrosis and cirrhosis prediction in chronic hepatitis C patients

In chronic hepatitis C (CHC), liver biopsy is the gold standard method for assessing liver histology, however it is invasive and can have complications. Non-invasive markers have been proposed and aspartate aminotransferase (AST)-to-platelet ratio index (APRI) has been shown as an easy and inexpensive marker of liver fibrosis. This study evaluated the diagnostic performance of APRI for significant fibrosis and cirrhosis prediction in CHC patients. This study included treatment-naive CHC patients who had undergone liver biopsy from January 2000 to August 2006. All histological slides were reviewed according to the METAVIR system. APRI was calculated based on laboratory results performed within four months from the biopsy. Twenty-eight (56 percent) patients had significant fibrosis (F2-F4) and 13 (26 percent) had cirrhosis (F4). The area under ROC curves of APRI for predicting significant fibrosis and cirrhosis were 0.92 (0.83-1.00) and 0.92 (0.85-1.00), respectively. Using cut-off values recommended by prior studies, significant fibrosis could be identified, in accordance with liver biopsy, in 44 percent and cirrhosis in 66 percent of patients. APRI could identify significant fibrosis and cirrhosis at a high degree of accuracy in studied patients.

Preditores de qualidade de vida em pacientes com doença renalcrônica em hemodiálise / Predictors of quality of life in chronic hemodialysis patients

Introdução: As terapias de caráter crônico apresentam três objetivos básicos: aumentar a longevidade, reduzir a morbidade e melhorar a qualidade devida (QV) dos pacientes. Possíveis associações entre dados demográficos e clínicos objetivos e a QV podem assegurar estratégias para melhoria do bemestarem portadores de doença renal crônica. Objetivo: Identificar fatores associados à QV de pacientes em hemodiálise regular. Metodologia: Foramentrevistados 114 renais crônicos em hemodiálise, utilizando-se o Medical Outcomes Study Questionaire 36-Item Short Form Health Survey (SF-36) paramedida da QV, e o Beck Depression Inventory para identificar a presença de depressão na amostra. A relação entre o nível de QV, depressão e outrasvariáveis clínicas, laboratoriais e sócio-demográficas foi analisada através da aplicação de modelo de regressão, com ajuste para as diversas co-variáveis.O método de Backward foi utilizado para seleção dos preditores de QV mais significativos (p<0,05). Resultados: Os pacientes tinham em média 46,3 ±13,9 anos, sendo 59,7% homens. Depressão esteve significativa e independentemente associada a pior QV em todas 8 as dimensões do SF-36. Outrasco-morbidades (diabetes e doença vascular periférica), acesso vascular por cateter, gênero masculino, idade mais avançada, ausência de ocupação regulare baixo nível de escolaridade também estiveram significativamente associados a menores pontuações em pelo menos uma das dimensões do SF-36 apósmúltiplos ajustes. Conclusão: Depressão foi o maior preditor de QV da amostra. Esta associação de pior QV com variáveis modificáveis ou preveníveisressalta a importância de intervenções psicossociais e médicas para melhoria do bem-estar de pacientes em hemodiálise.

Background: Chronic therapies have three basic objectives: to increase longevity, reduce mortality and increase patients´ quality of life (QoL). Possibleassociations between objective measurements and QoL can ensure strategies to improve the well-being in chronic kidney disease patients on hemodialysis.Objective: To identify variables associated with QoL among chronic hemodialysis patients. Methods: One hundred and fourteen end-stage renal diseasepatients on hemodialysis were interviewed. The Medical Outcomes Study Questionnaire 36-Item Short Form Health Survey (SF-36) was used to measurethe QoL level and the Beck Depression Inventory to identify depression. The association between QoL, depression and other clinical, laboratorial and sociodemographicvariables were assessed by means of multivariate regression analysis with adjustments for all baseline characteristics. The Backwardprocedure was used to correct P-values for multiple comparisons. Results: The patients were on average 46.3 ± 13.9 years old, and 59.7% were men.Depression was significantly and independently associated with worse QoL in all eight dimensions of the SF-36. Other comorbidities (diabetes andperipheral vascular disease), vascular access by catheter, male gender, advanced age, lack of a regular occupation, and low level of education were alsosignificantly associated with lower scores on at least one of the dimensions of the SF-36 after multiple adjustments. Conclusion: Depression was thestrongest predictor of QoL for the sample. Associations of poorer QoL with preventable or controllable factors emphasize the need for a greater focus onpsychosocial and medical interventions in order to improve the well-being of hemodialysis patients.