Research paper Comparison between nerve conduction study and high-resolution ultrasonography with color doppler in type 1 and type 2 leprosy reactions J. Akita ⇑ , L.H.G. Miller, F.M.C. Mello, J.A. Barreto, A.L. Moreira, M.H. Salgado, D.R. Kirchner, J.A. Garbino Neurophysiology Division, Lauro de Souza Lima Institute, Brazil article info Article history: Received 9 July 2020 Received in revised form 12 February 2021 Accepted 24 February 2021 Available online 17 March 2021 Keywords: Leprosy neuropathy Nerve conduction studies High-resolution ultrasonography and Color Doppler Leprosy reactions abstract Objective: To analyze the role of high-resolution ultrasonography with color Doppler (HRUS with CD) to diagnose inflammatory activity (IA) in nerves of leprosy patients under type 1 (RT1) and 2 (RT2) reactions compared to Nerve Conduction Studies (NCS). Methods: Leprosy patients with signs or symptoms suggestive of neuritis (RT1 and RT2) without corticos- teroids use were selected. They were evaluated by NCS and subsequently by HRUS with CD. Subacute seg- mental demyelination and the presence of blood flow, respectively, were considered signs of IA. The two methods were compared for their ability to diagnose patients with leprosy reactions. Results: A total of 257 nerves from 35 patients were evaluated. NCS and HRUS with CD diagnosed IA in 68% and 74% of patients, respectively. When both methods were used concomitantly, the diagnosis rate was 91.4%. HRUS with CD was particular helpful when there was minimal neurophysiological compro- mise in NCS or when motor potentials were not detected. Conclusion: HRUS with CD was able to detect leprosy reactions, especially when combined with NCS. It was especially useful in two opposite situations: nerves with only minor changes and those without motor response in NCS. Significance: Our data shows the usefulness of HRUS and CD, similar to NCS, as a tool to diagnose leprosy reactions. Ó 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). 1. Introduction Leprosy is among the main treatable causes of peripheral neu- ropathy in developing countries. The treatment challenge and prognosis lie in the adequate management of leprosy reactions (Graham et al., 2020; Schreuder, 1998). The reactions are acute epi- sodes of inflammatory response to a bacillary antigen in the nerve, classified as RT1 or RT2. RT1 is characterized by a predominant cel- lular immune response, which begins in the Schwann cell, where the bacillus has immunological specificity to bind inside. The RT2 occurs in the clinical forms with more humoral immune response. The RT2 develops a predominant humoral phenomenon due to the inefficient cellular immune response, leading to a greater bacillary quantity in the Schwann cells and in the nerve structures, conjunc- tive tissue and vessels. The response can provoke acute neu- trophilic inflammation with vasculitis and severe intraneural edema. Both reactions can evolve into hypervascularization, an increase in the volume of the nerve trunk and its entrapment in physiological tunnels, with worsening of demyelination and sec- ondary axonal loss (Alves et al., 2014; Tankisi et al., 2005). During the reactions, nerve conduction studies (NCS) reveal signs of demyelination that are related to inflammatory activity (IA). A pre- vious study showed that patients experiencing leprosy nerve reac- tions presented with characteristic demyelinated features, such as temporal dispersion, conduction block and pronounced reduction in conduction velocities at NCS, which improve after steroid treat- ment (Garbino et al., 2010). These NCS features of IA were shown in the classical model of inflammatory polyneuropathies, including chronic inflammatory demyelinating polyradiculopathy (CIDP) (Van den Bergh et al., 2010). Such signs of segmental demyelina- tion are also observed in acute or subacute nerve inflammatory injuries and can be used as signs of subacute IA (Garbino et al., 2010; Lau et al., 2020; Tankisi et al., 2005). Recently, studies utiliz- ing high-frequency ultrasound with color Doppler (HFUS with CD) in leprosy neuropathy have described characteristic changes in https://doi.org/10.1016/j.cnp.2021.02.003 2467-981X/Ó 2021 International Federation of Clinical Neurophysiology. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). ⇑ Corresponding author at: Department of Neurology, Psychology and Psychiatry, Botucatu School of Medicine – UNESP, Avenue Armando Alves, s/n, Botucatu, SP CEP 18618-686, Brazil. E-mail address: juliana.akita@unesp.br (J. Akita). Clinical Neurophysiology Practice 6 (2021) 97–102 Contents lists available at ScienceDirect Clinical Neurophysiology Practice journal homepage: www.elsevier.com/locate/cnp