PURPOSE OF REVIEW: This article provides a review of the clinical phenotypes and evaluation of peripheral nerve hyperexcitability syndromes. These rare diagnoses include cramp-fasciculation syndrome, Isaacs syndrome, and Morvan syndrome. Recent investigations have led to an understanding of the autoimmune underpinnings of these conditions and their specific associated antibodies. As the presentation of peripheral nerve hyperexcitability syndromes includes muscle stiffness, twitches, and spasms, which are also shared with certain central nervous system and myopathic conditions, the differential diagnosis of peripheral nerve hyperexcitability syndromes is reviewed. RECENT FINDINGS: Peripheral nerve hyperexcitability syndromes share clinical and electrodiagnostic evidence of motor nerve instability; however, their clinical presentations are varied. Case reviews have helped us understand the spectrum of symptoms associated with the three peripheral nerve hyperexcitability syndromes reviewed here: cramp-fasciculation syndrome, Isaacs syndrome, and Morvan syndrome. More recently, research has focused on understanding the voltage-gated potassium channel complex antibodies as well as neoplasms associated with these conditions. SUMMARY: The diagnosis of peripheral nerve hyperexcitability syndromes requires a high index of suspicion, support from the physical examination, familiarity with the spectrum of symptoms associated with peripheral nerve hyperexcitability syndromes, and recognition of diagnostic EMG features. Voltage-gated potassium channel complex antibodies are associated with these conditions. Optimum treatment and autoimmune pathogenesis remain areas of active research.
PURPOSE OF REVIEW: This article provides a review of the clinical phenotypes and evaluation of peripheral nerve hyperexcitability syndromes. These rare diagnoses include cramp-fasciculation syndrome, Isaacs syndrome, and Morvan syndrome. Recent investigations have led to an understanding of the autoimmune underpinnings of these conditions and their specific associated antibodies. As the presentation of peripheral nerve hyperexcitability syndromes includes muscle stiffness, twitches, and spasms, which are also shared with certain central nervous system and myopathic conditions, the differential diagnosis of peripheral nerve hyperexcitability syndromes is reviewed. RECENT FINDINGS:Peripheral nerve hyperexcitability syndromes share clinical and electrodiagnostic evidence of motor nerve instability; however, their clinical presentations are varied. Case reviews have helped us understand the spectrum of symptoms associated with the three peripheral nerve hyperexcitability syndromes reviewed here: cramp-fasciculation syndrome, Isaacs syndrome, and Morvan syndrome. More recently, research has focused on understanding the voltage-gated potassium channel complex antibodies as well as neoplasms associated with these conditions. SUMMARY: The diagnosis of peripheral nerve hyperexcitability syndromes requires a high index of suspicion, support from the physical examination, familiarity with the spectrum of symptoms associated with peripheral nerve hyperexcitability syndromes, and recognition of diagnostic EMG features. Voltage-gated potassium channel complex antibodies are associated with these conditions. Optimum treatment and autoimmune pathogenesis remain areas of active research.
Authors: Bas C Stunnenberg; Samantha LoRusso; W David Arnold; Richard J Barohn; Stephen C Cannon; Bertrand Fontaine; Robert C Griggs; Michael G Hanna; Emma Matthews; Giovanni Meola; Valeria A Sansone; Jaya R Trivedi; Baziel G M van Engelen; Savine Vicart; Jeffrey M Statland Journal: Muscle Nerve Date: 2020-05-27 Impact factor: 3.217
Authors: Dana Marafi; Nina Kozar; Ruizhi Duan; Stephen Bradley; Kenji Yokochi; Fuad Al Mutairi; Nebal Waill Saadi; Sandra Whalen; Theresa Brunet; Urania Kotzaeridou; Daniela Choukair; Boris Keren; Caroline Nava; Mitsuhiro Kato; Hiroshi Arai; Tawfiq Froukh; Eissa Ali Faqeih; Ali M AlAsmari; Mohammed M Saleh; Filippo Pinto E Vairo; Pavel N Pichurin; Eric W Klee; Christopher T Schmitz; Christopher M Grochowski; Tadahiro Mitani; Isabella Herman; Daniel G Calame; Jawid M Fatih; Haowei Du; Zeynep Coban-Akdemir; Davut Pehlivan; Shalini N Jhangiani; Richard A Gibbs; Satoko Miyatake; Naomichi Matsumoto; Laura J Wagstaff; Jennifer E Posey; James R Lupski; Dies Meijer; Matias Wagner Journal: Am J Hum Genet Date: 2022-08-09 Impact factor: 11.043