Neuropathic pain after brachial plexus avulsion - central and peripheral mechanisms

Abstract\ud \ud Review\ud The pain that commonly occurs after brachial plexus avulsion poses an additional burden on the quality of life of patients already impaired by motor, sensory and autonomic deficits. Evidence-based treatments for the pain associated with brachial plexus avulsion are scarce, thus frequently leaving the condition refractory to treatment with the standard methods used to manage neuropathic pain. Unfortunately, little is known about the pathophysiology of brachial plexus avulsion. Available evidence indicates that besides primary nerve root injury, central lesions related to the abrupt disconnection of nerve roots from the spinal cord may play an important role in the genesis of neuropathic pain in these patients and may explain in part its refractoriness to treatment.\ud \ud \ud Conclusions\ud The understanding of both central and peripheral mechanisms that contribute to the development of pain is of major importance in order to propose more effective treatments for brachial plexus avulsion-related pain. This review focuses on the current understanding about the occurrence of neuropathic pain in these patients and the role played by peripheral and central mechanisms that provides insights into its treatment.\ud \ud \ud Summary\ud Pain after brachial plexus avulsion involves both peripheral and central components; thereby it is characterized as a mixed (central and peripheral) neuropathic pain syndrome.Department of Neurology and by the Transcranial Magnetic Stimulation Laboratory of the Psychiatry Institute, University of São Paul

Characterization of pain, discriminative sensitivity and neuropathological findings in cutaneous biopsy of leprosy patients after finishing polychemotherapy treatment

A dor neuropática decorre do acometimento das vias somatossensitivas por lesão ou doença e afeta 7% da população geral. No entanto, apenas uma proporção dos doentes com neuropatia desenvolve este tipo de dor. Diversos estudos tentaram comparar doentes acometidos por lesões aparentemente semelhantes do sistema somatossensitivo em busca dos fatores determinantes para a ocorrência e características da dor neuropática, com resultados conflitantes. Parte deste insucesso deriva do fato de que indivíduos diferentes podem ter lesões de nervo semelhantes, mas diferem quanto ao perfil psicológico, epigenético, de polimorfismos de receptores de neurotransmissores, e de catastrofismo. Estas características e uma série de outros fatores interindividuais podem enviesar a interpretação dos achados locais sobre a área de neuropatia e dor. Assim, o estudo de um mesmo indivíduo que possua áreas diferentes de neuropatia com e sem dor neuropática concomitantes serviria para reduzir os vieses interindividuais nas suas avaliações, e poderia revelar alterações locais que se relacionem com a ocorrência de dor neuropática. A hanseníase é uma doença que afeta o sistema nervoso periférico com o padrão de mononeuropatia múltipla frequente. Uma grande proporção de doentes apresenta dor neuropática crônica que ocorre, na maior parte das vezes, após o fim do tratamento farmacológico antibioticoterápico, e que representa intenso impacto negativo na qualidade de vida. Assim, a hanseníase é um modelo de estudo em que um mesmo doente apresenta neuropatia periférica com dor neuropática (D+) em uma área do corpo (n+d+) e em outra parte do corpo (contralateral homóloga) pode apresentar neuropatia sem dor neuropática (n+d-). Ainda, há indivíduos que podem compor um grupo controle de doentes acometidos pela hanseníase, mas que não tem dor neuropática (D-), apresentando áreas de neuropatia sem dor neuropática (n+d-) e áreas corpóreas sem neuropatia (n-d-). O objetivo do presente estudo foi investigar fatores periféricos que poderiam implicar na ocorrência de dor neuropática avaliando doentes com antecedente de hanseníase e mononeuropatia múltipla como modelo. Foram avaliados 37 doentes com hanseníase e dor crônica (D+) e 22 doentes com hanseníase sem dor crônica (D-), grupo-controle. Realizou-se a caracterização sociodemográfica e clínica, exame neurológico padronizado e utilizou-se escalas de avaliação da dor padronizadas e validadas (Inventário Breve de Dor - IBD, Questionário de dor neuropática 4 (DN4), Questionário Breve de Dor McGill e Inventário de Sintomas de Dor Neuropática - ISDN). Sobre cada uma das quatro áreas presentes possíveis (n+d+; n+d-; n+d-; n-d-), realizou-se aferição da sensibilidade exteroceptiva e proprioceptiva por meio de limiares de sensibilidade dolorosa e não dolorosa pelo teste quantitativo de sensibilidade (TQS) e análise morfológico-quantitativa da densidade de fibras nervosas intraepidérmicas (DFNIE), associados à aferição da presença de fatores inflamatórios na neuropatologia cutânea. As formas paucibacilar e dimorfa da hanseníase apresentaram menor limiar de dor ao quente (LDoQ) em comparação com a forma multibacilar (-2,66?C e -4,25?C, p = 0,002, respectivamente). As áreas com dor neuropática apresentaram sinais de disfunção de fibras nervosas do tipo C e hiperestesia em comparação com áreas com neuropatia sem dor neuropática. O LDoQ foi maior em áreas com neuropatia e dor neuropática (47,5 ± 3,4) em comparação com áreas com neuropatia sem dor neuropática (45,9 ± 3,6), p = 0,010, enquanto o limiar de detecção mecânica (LDM) foi menor (1,5 ± 3,6) em áreas com neuropatia e dor neuropática em comparação com áreas com neuropatia sem dor neuropática (5,8 ± 29,6), p = 0,047. Os doentes hansênicos apresentaram diagnóstico de neuropatia de fibras finas grave em todas as áreas de pele amostradas, a média das densidades variaram entre 2,1 a 3,2 fibras por milímetro (abaixo do percentil 5%). Não houve diferença estatisticamente significativa entre as quatro diferentes áreas quanto à DFNIE e quanto a fatores inflamatórios como contagens de macrófagos, linfócitos, células de Langerhans e medida da citocina fator de necrose tumoral alfa. Na modelagem matemática das variáveis significativas, as áreas com neuropatia sem dor tiveram LDoQ 2,30?C mais altos do que as áreas sem neuropatia e sem dor (n-d-). As áreas com neuropatia com dor (n+d+) tiveram LDoQ 3,45 C mais altos do que as áreas sem neuropatia e sem dor (n-d-). Nas análises de modelagem da relação dos dados entre LDoQ e DFNIE, verificou-se que áreas totalmente desnervadas (DFNIE = 0/mm apresentaram aumento do LDoQ estimada de 4,03 C, enquanto as amostras parcialmente inervadas (DFNIE = 1-5fibras/mm) apresentaram um aumento estimado de LDoQ de 1,54 C em comparação às áreas de referência (DFNIE >- 5fibras/mm). Encontrou-se uma relação entre o tempo e o agravamento da neuropatia. A cada mês, decorrido entre o término do tratamento com antibióticos da hanseníase e a avaliação atual, o LDoQ aumentou em 0,03?C, reforçando teorias de que a presença de debris bacterianos podem estar relacionados à ocorrência de neuropatia ativa e vigente, assim como, um potencial papel das reações hansênicas na ocorrência de neuropatia e dor neuropática a longo prazo. As alterações do LDoQ e do LDM foram relacionadas à ocorrência da dor neuropática no presente estudo e podem ter valor prognóstico e de rastreio se esses achados forem replicados em coortes maiores no futuroNeuropathic pain arises from a lesion or disease of the somatosensory system and affects 7% of the general population. However, only a proportion of patients with neuropathy develop this type of pain. Several studies have attempted to compare patients with apparently similar lesions to the somatosensory system in search of the factors determining the occurrence and characteristics of neuropathic pain, yielding conflicting results. Part of the challenge in such assessment stems from the fact that different individuals may have similar nerve lesions, but may differ in their psychological, epigenetic, neurotransmitter receptor polymorphisms and catastrophism profiles. These features and several other interindividual factors may bias the interpretation of local findings in the area of neuropathy and pain. Thus, the study of the same individual who presents with different areas of neuropathy with and without neuropathic pain concomitantly would reduce the interindividual bias of these assessments, and could reveal local changes related to the occurrence of neuropathic pain. Leprosy is a disease that affects the peripheral nervous system with the frequent pattern of multiple mononeuropathy distribution. A large proportion of patients present chronic neuropathic pain, which occurs most often after the end of the antibiotic therapy drug treatment, and which poses an intense negative impact on the quality of life. Thus, leprosy is a \"model\" in which the same patient presents peripheral neuropathy with neuropathic pain (P+) in one area of the body (n+p+) and in another part of the body (contralateral homologous) presents neuropathy without neuropathic pain (n+p-). In addition, there are individuals who may constitute a control group, who are affected by leprosy but who do not have neuropathic pain (P-), and have body areas with neuropathy without neuropathic pain (n+p-) and body areas without neuropathy (n-p-). The aim of the present study was to investigate peripheral factors that could be related to the occurrence of neuropathic pain by assessing patients with leprosy and multiple mononeuropathy. We evaluated 37 patients with leprosy and chronic pain (P+) and 22 patients with leprosy without chronic pain (P-) (control group). Sociodemographic and clinical characterization were performed, as well as, standardized neurological examination and assessment of pain and related symptoms with validated pain assessment scales (Brief Pain Inventory - BPI, Neuropathic Pain Questionnaire 4 - DN4, McGill Brief Pain Questionnaire and Neuropathic Pain Symptom Inventory - NPSI). On each of the four possible body areas (n+p+; n+p-; n+p-; n-p-), exteroceptive and proprioceptive sensitivity were assessed by means of thresholds of painful and non-painful sensory stimuli by quantitative sensitivity test (QST), as well as, morphological-quantitative analysis of intraepidermal nerve fiber density (IENFD), and assessment of inflammatory factors in cutaneous neuropathology. Paucibacillary and dimorphic forms of leprosy presented lower heat pain threshold (HPT) compared to the multibacillary form (-2.66?C and -4.25 C, p=0.002; respectively). Areas with neuropathic pain had signs of defective C nerve fiber dysfunction and hyperesthesia compared to areas with neuropathy without neuropathic pain. HPT was higher in areas with neuropathy and neuropathic pain (47.5 ± 3.4) compared to areas with neuropathy without neuropathic pain (45.9 ± 3.6), p=0.010), while mechanical detection threshold (MDT) was lower (1.5 ± 3.6) in areas with neuropathy and neuropathic pain compared to areas with neuropathy without neuropathic pain (5.8 ± 29.6), p=0.047. Leprosy patients had a diagnosis of severe small-fiber neuropathy in all areas of skin sampled, the mean densities ranged from 2.1 to 3.2 fibers per millimeter (below 5% percentile). There was no statistically significant difference between the four different areas concerning IEFND and for inflammatory factors such as presence of number of macrophages, lymphocytes, Langerhans cells and cytokine tumor necrosis factor alpha. In the mathematical modeling of significant variables, areas with painless neuropathy (n+p-) had a HPT 2.30?C higher than areas without neuropathy and without pain (n-p-). Areas with neuropathy with pain (n+p+) had a HPT 3.45 C higher than areas without neuropathy and without pain (n-p-). In the modeling analyses between the relationship of HPT and IEFND data, it was found that totally denervated areas (IEFND=0/mm) presented an increase in estimated HPT of 4.03 C, while scarcely innervated samples (IEFND=1-5fibers/mm) presented an estimated increase of HPT of 1.54?C compared to reference areas (IEFND >- 5fibers/mm). We found a relationship between time and worsening of neuropathy. Each month between the termination of the leprosy antibiotic treatment and the present assessment, HPT increased by 0.03°C, supporting theories relating the presence of bacterial debris and the occurrence of active and ongoing neuronal damage, as well as, a potential role of leprosy reactions in the occurrence of neuropathy and neuropathic pain in the long-term. HPT and MDT changes were related to the occurrence of neuropathic pain in the present study and may have prognostic and screening value should these findings be replicated in larger cohorts in the futur

Diagnostic disclosure in Alzheimer's disease: A review

Abstract Although growing, the literature on research into attitudes of general and specialized physicians towards disclosing the diagnosis of dementia and Alzheimer's disease (AD), or the current practice on AD disclosure, remains limited. Moreover, information is also scarce on what caregivers, or indeed patients themselves, wish to know with regard to their diagnosis. The goal of the present article was to present a review of the current available literature on the topic of truth telling in dementia, especially in AD. The studies discussed in this review were mainly conducted in Europe, particularly in the United Kingdom, as well as the United States. Disclosure of AD diagnosis is not a common practice among physicians. In the clinical context, the discussion on diagnosis disclosure can be valuable for improving the care of AD patients and their families

Caramelli P. Diagnostic disclosure in Alzheimer’s disease. Dement Neuropsychol

Abstract -Although growing, the literature on research into attitudes of general and specialized physicians towards disclosing the diagnosis of dementia and Alzheimer's disease (AD), or the current practice on AD disclosure, remains limited. Moreover, information is also scarce on what caregivers, or indeed patients themselves, wish to know with regard to their diagnosis. The goal of the present article was to present a review of the current available literature on the topic of truth telling in dementia, especially in AD. The studies discussed in this review were mainly conducted in Europe, particularly in the United Kingdom, as well as the United States. Disclosure of AD diagnosis is not a common practice among physicians. In the clinical context, the discussion on diagnosis disclosure can be valuable for improving the care of AD patients and their families. Key words: dementia, Alzheimer's disease, truth disclosure, diagnosis disclosure, bioethics. Revelação diagnóstica na doença de Alzheimer: uma revisão Resumo -O conhecimento científico ainda é limitado, embora crescente, a respeito das atitudes de médicos generalistas e especialistas sobre a revelação do diagnóstico de demência e da doença de Alzheimer (DA), ou ainda em relação à prática atual na revelação diagnóstica da DA. As informações também são escassas sobre o que cuidadores e os próprios pacientes querem saber sobre o seu diagnóstico. O objetivo deste artigo é apresentar uma revisão da literatura disponível atualmente sobre revelação diagnóstica em demência, especialmente na DA. Os estudos discutidos nesta revisão foram feitos principalmente na Europa, a maioria no Reino Unido, e nos Estados Unidos. A revelação diagnóstica da DA não é uma prática comum entre os médicos. No contexto clinico, esta discussão pode ser útil para melhorar o tratamento dos pacientes com DA e a atenção a seus familiares. Palavras-chave: demência, doença de Alzheimer, revelação da verdade, revelação diagnóstica, bioética

Alzheimer`s disease diagnosis disclosure in Brazil: a survey of specialized physicians` current practice and attitudes

Background: There is little, though growing, interest in the research area of attitudes held among physicians towards disclosing the diagnosis of dementia and Alzheimer`s disease (AD), or the current practice on AD disclosure. This study aimed to investigate the practice and attitudes of specialized physicians towards AD diagnosis disclosure in Brazil. Methods: A questionnaire was devised to survey the current practice and attitudes regarding diagnosis disclosure of AD in Brazil and sent to specialized physicians (170 geriatricians, 300 neurologists and 500 psychiatrists) by electronic mail. Results: From 970 potential respondents, 181 physicians who usually attend AD patients returned the questionnaire. There were no significant differences between the three specialties regarding the frequency with which they informed patients of their AD diagnosis (p = 0.17). The results revealed that only 44.8% of the physicians would regularly inform the patient of the diagnosis, although 85.6% of these use clear terminology. Despite their usual practice, 76.8% would want to know their diagnosis if they themselves were affected by AD. Conclusions: Disclosure of AD diagnosis is not common among specialized physicians in Brazil and different factors are involved. In the clinical context, discussion on advantages of diagnosis disclosure can be useful for improving the care of AD patients and their families

qEEG spectral peak in Alzheimer's disease: A possible tool for treatment follow-up

Abstract qEEG spectral analysis has been considered highly sensitive to cortical functional changes and agrees strongly with the clinical diagnosis of AD. The sensitivity of spectral analysis has ranged from 71% to 81% in several studies.1-3. Objective: The aim of this study was to retrospectively evaluate whether alpha qEEG spectral peak can supplement clinical examination by constituting an independent tool to monitor treatment and follow-up of dementia progression in Alzheimer's disease (AD). In addition, we examined the demographic data and alpha power spectra distribution of patients and elderly normal controls. Methods: qEEGs were selected from 2 groups of patients: normal controls (n=30), and patients who fulfilled criteria for mild probable AD diagnosis (n=41). The alpha qEEG spectral analysis and MMSE were performed once or twice a year. Results: In our groups, MMSE scores and qEEG alpha spectral peak were unchanged (no statistical differences) after anticholinesterase use where qEEG spectral peak was never lower than 8 Hz in the control group. Conclusion: This study supports two important concepts. First, 8 Hz alpha appears to be the lowest awake spectral peak compatible with normality. And finally, in a clinical context, qEEG is a valuable diagnostic tool that could prove useful for Dementia follow-up