[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-0-en-105":3,"doc-seo-455537-105":59,"doc-detail-455537-en":131},{"code":4,"msg":5,"data":6},0,"success",[7,13,18,23,28,33,38,43,48,51,55],{"id":8,"doc_module":4,"doc_module_name":9,"category_name":10,"show_sort_weight":11,"slug":12},1,"Document","Story & Novel",90,"story-novel",{"id":14,"doc_module":4,"doc_module_name":9,"category_name":15,"show_sort_weight":16,"slug":17},2,"Literature",80,"literature",{"id":19,"doc_module":4,"doc_module_name":9,"category_name":20,"show_sort_weight":21,"slug":22},4,"Exam",70,"exam",{"id":24,"doc_module":4,"doc_module_name":9,"category_name":25,"show_sort_weight":26,"slug":27},5,"Comic",60,"comic",{"id":29,"doc_module":4,"doc_module_name":9,"category_name":30,"show_sort_weight":31,"slug":32},6,"Technology",50,"technology",{"id":34,"doc_module":4,"doc_module_name":9,"category_name":35,"show_sort_weight":36,"slug":37},7,"Healthcare",40,"healthcare",{"id":39,"doc_module":4,"doc_module_name":9,"category_name":40,"show_sort_weight":41,"slug":42},8,"Research & Report",30,"research-report",{"id":44,"doc_module":4,"doc_module_name":9,"category_name":45,"show_sort_weight":46,"slug":47},9,"Religion & Spirituality",20,"religion-spirituality",{"id":46,"doc_module":4,"doc_module_name":9,"category_name":49,"show_sort_weight":46,"slug":50},"World Cup","world-cup",{"id":52,"doc_module":4,"doc_module_name":9,"category_name":53,"show_sort_weight":52,"slug":54},10,"Lifestyle","lifestyle",{"id":56,"doc_module":4,"doc_module_name":9,"category_name":57,"show_sort_weight":24,"slug":58},19,"General","general",{"code":4,"msg":60,"data":61},"ok",{"site_id":62,"language":63,"slug":64,"title":65,"keywords":66,"description":67,"schema_data":68,"social_meta":124,"head_meta":126,"extra_data":128,"updated_unix":130},105,"en","rare-acute-exacerbation-of-lewis-sumner-syndrome-mimicking-stroke-a-case-report","Rare acute exacerbation of lewis-sumner syndrome mimicking stroke: a case report","","LETTER TO THE EDITOR focusing on a rare acute worsening of Lewis-Sumner syndrome (LSS/MADSAM) that clinically mimicked an acute cerebrovascular event during an Influenza A infection. A 63-year-old man with multifocal demyelinating neuropathy remained stable on initial corticosteroids, then responded to IVIg. In January 2025 he developed sudden hemiparesis and rapidly progressive respiratory and cranial-nerve dysfunction; CT/CTA were unrevealing. Influenza A (H1N1) was found on bronchoalveolar lavage, and repeat EMG supported demyelination with conduction blocks. A five-day IVIg course (2 g/kg) produced rapid neurological and respiratory improvement.",{"@graph":69,"@context":123},[70,84,106],{"@type":71,"itemListElement":72},"BreadcrumbList",[73,77,79,82],{"item":74,"name":75,"@type":76,"position":8},"https://docshare.wps.com","Home","ListItem",{"item":78,"name":9,"@type":76,"position":14},"https://docshare.wps.com/document/",{"item":80,"name":35,"@type":76,"position":81},"https://docshare.wps.com/document/healthcare/",3,{"item":83,"name":65,"@type":76,"position":19},"https://docshare.wps.com/document/rare-acute-exacerbation-of-lewis-sumner-syndrome-mimicking-stroke-a-case-report/455537/",{"url":83,"name":65,"@type":85,"image":86,"author":91,"headline":65,"publisher":94,"fileFormat":97,"inLanguage":63,"description":67,"dateModified":98,"datePublished":99,"encodingFormat":97,"isAccessibleForFree":100,"interactionStatistic":101},"DigitalDocument",{"url":87,"@type":88,"width":89,"height":90},"https://docshare.wps.com/thumbnails/rare-acute-exacerbation-of-lewis-sumner-syndrome-mimicking-stroke-a-case-report/455537.png","ImageObject",300,407,{"name":92,"@type":93},"Hazel","Person",{"url":74,"name":95,"@type":96},"DocShare","Organization","application/pdf","2026-10-31","2026-09-30",true,{"@type":102,"interactionType":103,"userInteractionCount":105},"InteractionCounter",{"@type":104},"ViewAction",13,{"@type":107,"mainEntity":108},"FAQPage",[109,115,119],{"name":110,"@type":111,"acceptedAnswer":112},"What condition was described and why did it mimic stroke?","Question",{"text":113,"@type":114},"The report describes a rare acute exacerbation of Lewis-Sumner syndrome (LSS/MADSAM) that presented with sudden severe hemiparesis, prompting evaluation for an acute cerebrovascular event. Imaging (CT/CTA) was unremarkable, and the clinical course was ultimately consistent with an acute immune-mediated neuropathy relapse.","Answer",{"name":116,"@type":111,"acceptedAnswer":117},"How was the original diagnosis of multifocal CIDP/LSS supported?",{"text":118,"@type":114},"The patient’s history and investigations showed multifocal demyelinating polyneuropathy with motor and sensory conduction blocks. Antiganglioside antibodies were negative, and European guidelines supported a diagnosis of multifocal CIDP (LSS variant).",{"name":120,"@type":111,"acceptedAnswer":121},"What treatment led to rapid improvement during the acute deterioration?",{"text":122,"@type":114},"A five-day course of intravenous immunoglobulins (IVIg, 2 g/kg) was initiated for suspected acute exacerbation of chronic demyelinating disease. The patient improved rapidly in neurological status and respiratory function immediately after the infusions.","https://schema.org",{"og:url":83,"og:type":125,"og:title":65,"og:site_name":95,"og:description":67},"article",{"robots":127,"canonical":83},"index,follow",{"doc_id":129,"site_id":62},455537,1790792143,{"code":4,"msg":5,"data":132},{"doc_id":129,"user_id":133,"nickname":92,"user_avatar":134,"doc_module":4,"category_id":34,"category_name":35,"doc_title":65,"doc_description":67,"doc_content":135,"file_id":136,"file_url":137,"file_type":138,"file_size":139,"view_count":105,"is_deleted":4,"is_public":8,"is_downloadable":8,"audit_status":8,"page_count":81,"language":140,"language_code":63,"site_id":62,"html_lang":63,"table_of_contents":141,"faqs":142,"seo_title":143,"seo_description":67,"update_tm":144,"read_time":39,"preview_page_count":4},137441390410,"https://ap-avatar.wpscdn.com/avatar/2000252f4ab5702993?_k=1776741390130283984","Neurological Sciences (2026) 47:105  \n[https://doi.org/10.1007/s10072-025-08609-6](https://doi.org/10.1007/s10072-025-08609-6)  \nLETTER TO THE EDITOR  \nRare acute exacerbation of lewis-sumner syndrome mimicking stroke: a case report  \nS. Mambriani1,2 · R. Brusa2 · L. Politini2 · A. C. Prelle1,2  \nReceived: 28 July 2025 / Accepted: 27 November 2025 / Published online: 6 January 2026 © Fondazione Società Italiana di Neurologia 2026  \nLewis-Sumner syndrome (LSS), or multifocal acquired demyelinating sensory and motor neuropathy (MADSAM), is a rare variant of chronic inflammatory demyelinating polyneuropathy (CIDP) characterized by persistent conduction blocks in motor and sensory nerves. LSS accounts for 5–10% of CIDP cases, with a prevalence of 1–9/1,000,000 [1] . While the exact cause of this condition is not fully understood, there are several factors believed to contribute to its development, in particular autoimmune disorders and viral infections. We describe an acute exacerbation of LSS during an infection of Influenza A virus, supporting hypothesis of an immune-mediated etiology.  \nWe present the case of a 63-year-old man affected by LSS. In 2017, he has developed a deficit in dorsiflexion of the left foot and paresthesia in the hands, with a prevalence of the left one; in 2019, following a clinical worsening, he was hospitalized and the lumbar puncture revealed albumino-cytological dissociation (white cells: 2/uL, protein: 80 mg/dL) in the Cerebrospinal fluid (CSF) . Nerve conduction studies and electromyography showed a multifocal demyelinating polyneuropathy with motor and sensitive conduction blocks affecting both upper and lower limb with an asymmetric pattern. Antiganglioside IgG and IgM antibodies, like anti-GQ1b, antiGM1, anti-GD1a, anti-GD1band anti-GM2 were negative. According to the European guidelines [2], the diagnosis of multifocal CIDP was made.  \nThe clinical picture remained almost unchanged with the initial corticosteroids therapy. He responded to intravenous immunoglobulins (IVIg), albeit with an early end-of-dose  \n􀀍 S. Mambriani [silvia.mambriani@unimi.it](silvia.mambriani@unimi.it)  \nA. C. Prelle [alessandro.prelle@unimi.it](alessandro.prelle@unimi.it)  \n1 Università Degli Studi Di Milano, Milano, Italy  \n2 Neurologia-Stroke Unit, Dipartimento Di Neuroscienze, ASST Ovest MI, Sede Di Legnano, Italy  \neffect after three weeks. In the following months, he had good control of the symptoms with the weekly administration of intravenous immunoglobulins (30–35 g per week), with an inflammatory neuropathy cause and treatment (INCAT) disability score of 2 point (mild weakness of the interosseous and finger extensors, deficit of dorsiflexion of the left foot) .  \nIn January 2025, during a routine IVIg infusion, he developed sudden severe left brachio-crural hemiparesis, prompting urgent neurological evaluation and imaging studies for suspected acute cerebrovascular event. Brain CT and intracranial CT angiography were unremarkable. Blood tests were normal except for a modest increase in creatine kinase (a known finding). Given his history of hypertension and clinical presentation, the patient underwent intravenous thrombolysis with Alteplase without neurological benefit. Within 24 h, he developed fever, significant desaturation requiring continuous positive airway pressure (CPAP) ventilation, tetraparesis, areflexia, dysphagia, dysarthria, and subsequently diplopia. Due to progressive respiratory deterioration, the patient was intubated and admitted to the Intensive Care Unit with the INCAT disability score of 10. He presented significant involvement of the cranial nerves, with diplopia in all directions of gaze, moderate deficit of both the superior and inferior component of the VII right cranial nerve, dysphagia with difficulty in managing secretions. Suspecting an acute exacerbation of his known chronic demyelinating disease, a five-day course of IVIg (2 g/kg) was initiated, leading to rapid improvement in neu","cbCainxa8nNxCqRJ","https://ap.wps.com/l/cbCainxa8nNxCqRJ","pdf",536981,"English","# Letter to the editor\n## Background and rationale\n## Case presentation\n## Diagnostics and monitoring\n## Treatment and outcome","[{\"question\":\"What condition was described and why did it mimic stroke?\",\"answer\":\"The report describes a rare acute exacerbation of Lewis-Sumner syndrome (LSS/MADSAM) that presented with sudden severe hemiparesis, prompting evaluation for an acute cerebrovascular event. Imaging (CT/CTA) was unremarkable, and the clinical course was ultimately consistent with an acute immune-mediated neuropathy relapse.\"},{\"question\":\"How was the original diagnosis of multifocal CIDP/LSS supported?\",\"answer\":\"The patient’s history and investigations showed multifocal demyelinating polyneuropathy with motor and sensory conduction blocks. Antiganglioside antibodies were negative, and European guidelines supported a diagnosis of multifocal CIDP (LSS variant).\"},{\"question\":\"What treatment led to rapid improvement during the acute deterioration?\",\"answer\":\"A five-day course of intravenous immunoglobulins (IVIg, 2 g/kg) was initiated for suspected acute exacerbation of chronic demyelinating disease. The patient improved rapidly in neurological status and respiratory function immediately after the infusions.\"}]","Rare acute exacerbation of lewis-sumner syndrome mimicking stroke: a case report | PDF",1790743359]