Dor neuropática na prática clínica: ênfase nos instrumentos diagnósticos / Neuropathic pain in clinical practice: emphasis on diagnostic tools

A dor neuropática é causada por uma lesão ou doença do sistema nervoso somatossensitivo. Trata-se de uma manifestação sindrômica que envolve mecanismos inflamatórios e imunes com fisiopatologia ainda pouco esclarecida. O espectro de apresentação da dor neuropática é amplo e, assim, constitui um desafio na prática clínica. Este problema de saúde pública necessita de ampla capacidade técnica dos clínicos generalistas. Torna-se relevante identificar o potencial de cronificação do sintoma e adotar abordagens mitigantes do processo lesivo, estrutural e emocional. Nesse sentido, o diagnóstico adequado da dor neuropática é o primeiro passo na abordagem ao paciente. Diante disso, essa revisão objetiva facilitar a melhor escolha dos métodos diagnósticos no manejo clínico do paciente. Dentre estes, é possível citar a imagem por ressonância magnética funcional, eletroneuromiografia, tomografia por emissão de pósitrons, microneurografia, teste quantitativo sensorial, biópsias de pele, estudos de condução nervosa e de potencial somatossensorial evocado. A dor, por ser um processo sensorial subjetivo, apresenta amplo espectro de manifestações clínicas. Por essa razão, é possível fazer uso de técnicas como métodos de triagem e exames complementares para um diagnóstico mais específico.

Neuropathic pain is caused by an injury or illness of the somatosensory nervous system. It is a syndromic manifestation that involves inflammatory and immune mechanisms, whose pathophysiology is still poorly understood. The spectrum of presentation of neuropathic pain is wide and, therefore, it is a challenge in clinical practice. This public health problem requires the broad technical capacity of general practitioners. It is relevant to identify the potential for chronicity of the symptom and adopt mitigating approaches to the harmful, structural, and emotional process. In this sense, the proper diagnosis of neuropathic pain is the first step in approaching the patient. Therefore, this review aims to facilitate the best choice of diagnostic methods in the clinical management of the patient. Among these, functional magnetic resonance imaging, electroneuromyography, positron emission tomography, microneurography, quantitative sensory testing, skin biopsies, nerve conduction and evoked somatosensory potential studies are possible. Pain, being a subjective sensory process, has a wide spectrum of clinical manifestations. For this reason, it is possible to make use of techniques such as screening methods and complementary exams for a more specific diagnosis.

A-waves associated are with neuropathic pain in leprosy

Introduction/Aims:The A-wave is a late response related either to demyelination or early axonal regeneration. It may be helpful in the evaluation of some peripheral neuropathies. In leprosy, previous studies suggested that A-waves could be a neurophysiological marker of pain in patients during reactions. Herein we have attempted to further assess the profile and clinical correlates of A-waves by exploring a large leprosy cohort. Methods: Between 2015 and 2018, 63 patients with leprosy (47 men and 16 women) had A-waves in nerve conduction studies and were included in this study. We included patients regardless of whether they were experiencing leprosy reactions ornot. We then compared clinical features in nerves with and without A-waves. Results:The mean age of study participants was 46.5 ± 12.3 years and most had borderline leprosy. From this cohort, we assessed separately 83 motor nerves that demonstrated A-waves (group A+) and 29 motor nerves that did not demonstrate A-waves (group A-). Neuropathic pain (NP) was found in 66 of 83 nerves in group A+,but only 5 of 29 in group A-(79.5 vs 17.2%,P< .001). In contrast, no significant between-group difference emerged regarding presence of reactions, sensory function (based on Semmes-Weinstein evaluations), or muscle strength. A-waves were found in nerves with neuropathic pain experiencing (39 of 66=59%) or not experiencing (27 of 66=41%) leprosy reactions. Discussion: These results show that A-waves are associated with neuropathic pain in leprosy patients, regardless of the nerves affected and the immune status (in reaction or not).