Association Between Neuropathic Pain and A-Waves in Leprosy Patients With Type 1 and 2 Reactions

Abstract

Neuropathic pain (NP) is a well-recognized feature of leprosy neuropathy. However, the diagnosis of NP is difficult using only clinical criteria. In the study reported here, by means of conventional nerve conduction studies, the authors sought for an association between long-latency responses and NP complaints in leprosy patients with type 1 and 2 reactions. Of the 27 ulnar nerves of leprosy patients, 18 with type 1 reaction (T1R) and 9 with type 2 reaction (T2R) were followed-up for 6 months before and after steroid treatment. Clinical characteristics of pain complaints and clinical function were assessed, as well as the presence of F- and A-waves of the ulnar nerve using nerve conduction studies. The clinical and the neurophysiologic findings were compared to note positive concordances (presence of NP and A-waves together) and negative concordances (absence of NP and A-waves together) before and after treatment. Both reactions presented a high frequency of A-waves (61.1% in T1R and 66.7% in T2R, P < 0.05) and prolonged F-waves (69.4% in T1R and 65.8% in T2R, P = 0.4). No concordances were seen between pain complaints and F-waves. However, significant concordances between NP and A-waves were observed, although restricted to the T2R group (χ(2) = 5.65, P = 0.04). After treatment, there was a significant reduction in pain complaints, as well as the presence of F- and A-waves in both groups (P < 0.05 for all comparisons). In conclusion, the presence of A-waves correlates well with pain complaints of neuropathic characteristics in leprosy patients, especially in those with type 2 reaction. Probably, such response shares similar mechanisms with the small-fiber dysfunction seen in these patients with NP, such as demyelination, intraneural edema, and axonal sprouting. Further studies using specific tools for small-fiber assessment are warranted to confirm our findings.

Leprosy neuropathy: clinical presentations

“…Probably, such response shares similar mechanisms with the small-fiber dysfunction seen in these patients with NP, such as demyelination, intraneural edema, and axonal sprouting. Further studies using specific tools for small-fiber assessment are warranted to confirm these findings 27 . Complex regional pain syndrome (CRPS/Sudeck' s dystrophy) is a painful and disabling condition -a triad of autono mic, sensory, and motor symptoms disproportionate to the inciting event (inflammatory, infectious, or traumatic).…”

“…Painful symptoms were also referred by 42.1% of 19 PNL patients 6 . The presence of A-waves in conduction studies correlates well with pain complaints of neuropathic characteristics in leprosy patients, especially in those with type 2 reaction 27 . Probably, such response shares similar mechanisms with the small-fiber dysfunction seen in these patients with NP, such as demyelination, intraneural edema, and axonal sprouting.…”

Clinical and Neurophysiological Features of Leprosy Patients with Neuropathic Pain

“…[2][3][4] It is common for neuritis to be associated with certain features of NP, making it difficult to reach correct differential diagnostic and to decide the best treatment. 5 During neuritis, deterioration of the nerve function associated with pain usually recovers after administration of oral steroids. 6 On the other hand, NP relief most often occurs as a result of tricyclic antidepressives, dual reuptake inhibitors of serotonin and norepinephrine, anticonvulsivant drugs, and topical anesthetics.…”

Mensuração do ângulo articular do cotovelo no teste de tensão neural em indivíduos com hanseníase

“…Verificou-se, após a avaliação, que não houve diferença estatisticamente significativa entre esses grupos, demonstrando que a alteração de sensibilidade não influenciou na amplitude de movimento. Garbino et al 6 alegam que a dor neuropática hansênica está relacionada à desmielinização e edema intraneural que afetam tanto fibras grandes como pequenas concomitantemente. Durante a realização da manobra, os pacientes relataram dor, queimação e parestesia e/ou resistência ao movimento, corroborando com os achados nesta pesquisa 20 .…”

“…Com relação ao comprometimento de trajeto nervoso, o nervo ulnar é o mais acometido nos membros superiores. É importante ressaltar que no Brasil aproximadamente 23% dos pacientes com hanseníase apresentam algum tipo de incapacidade após a alta [4][5][6] . Na hanseníase ocorre uma grande incidência de neurites e síndromes compressivas.…”