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Papers of the Week


Papers: 13 Aug 2022 - 19 Aug 2022

RESEARCH TYPE:
Psychology


2022 Aug 15


Pain

Mirror peripheral neuropathy and unilateral chronic neuropathic pain: insights from asymmetric neurological patterns in leprosy.

Authors

Raicher I, Zandonai AP, Anghinah IW, Frassetto M, Stump P R, Trindade MAB, Harnik S, Oliveira RA, Macarenco RSS, Doppler K, Üçeyler N, Mello ES, Sommer C, Teixeira MJ, Galhardoni R, de Andrade DC
Pain. 2022 Aug 15.
PMID: 35972460.

Abstract

Leprosy-related multiple mononeuropathy offers a pattern of impairment where neuropathy with and without neuropathic pain (NeP) are present in the same individual, thus allowing to investigate peripheral sensory and innervation in both conditions. This cross-sectional study collected data on clinical and neurological examination, pain-assessment questionnaires, quantitative sensory test, and intraepidermal nerve fiber density (IENFD) of patients with leprosy and divided the cohort into two groups: with (P+) and without NeP (P-). Further, we assessed mirror body areas in the same NeP individuals with bilateral neuropathy also presenting unilateral NeP. Pain-free patients having unilateral neuropathy were controls. A total of 37 P+ patients and 22 P- patients were evaluated. Limb areas with NeP had signs of C-fiber dysfunction and hyperesthesia on QST compared with limb areas having neuropathy without NeP. Skin denervation was found in all leprosy patients. Comparisons of limbs with and without neuropathy, and with and without NeP revealed that higher heat pain thresholds (HPT) were associated with neuropathic pain areas, whereas less altered HPT was correlated with higher fiber density. Furthermore, a relationship was found between time of leprosy treatment termination and more intense neuropathy, expressed by HPT increasing 0.03 °C each month. As expected, interindividual comparisons failed to show differences in IENFD and subepidermal plexus areas between patients P+ and P- (p=0.2980, p = 0.9044; respectively). Higher HPT and lower mechanical detection threshold were related to NeP. The present study pointed out the relevance of intra-individual comparisons including mirror areas when assessing local changes in peripheral NeP.