{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T16:57:11Z","timestamp":1785430631621,"version":"3.56.0"},"reference-count":12,"publisher":"Department of Medicine, Warren Alpert Medical School at Brown University","issue":"3","license":[{"start":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T00:00:00Z","timestamp":1782864000000},"content-version":"unspecified","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by-nc\/4.0"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":[],"abstract":"<jats:p>Powassan virus (POWV) is a rare tick-borne flavivirus that can cause severe neuroinvasive disease with high morbidity and mortality. Early clinical and radiographic features are often nonspecific and may mimic acute ischemic stroke, leading to diagnostic delay. We report the case of a 77-year-old woman with recent tick exposure who presented with acute-onset focal neurologic deficits and fever. Initial neuroimaging demonstrated focal diffusion restriction, raising concern for acute ischemic stroke, and dual antiplatelet therapy was initiated. Over subsequent days, the patient developed progressive encephalopathy, persistent high-grade fevers, and worsening weakness. Repeat magnetic resonance imaging revealed rapidly evolving T2\/FLAIR hyperintensities involving the basal ganglia, cortical gray matter, subcortical white matter, and cerebellum, consistent with viral encephalitis. Cerebrospinal fluid analysis demonstrated pleocytosis and elevated protein, and cerebrospinal fluid testing confirmed Powassan virus infection. Despite guideline-concordant empiric antimicrobial and antiviral therapy and aggressive supportive care, the patient experienced rapid neurologic decline requiring mechanical ventilation and ultimately progressed to quadriparesis and locked-in syndrome. Care was transitioned to comfort measures only, and the patient died shortly thereafter. This case highlights the aggressive clinical course of Powassan virus encephalitis and underscores its potential to mimic acute ischemic stroke in the early stages. In patients from endemic regions presenting with fever and rapidly progressive neurologic deficits, early consideration of Powassan virus and other arboviral encephalitides is essential to guide diagnostic evaluation and prognostication.<\/jats:p>","DOI":"10.56305\/001c.162035","type":"journal-article","created":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T12:42:25Z","timestamp":1782909745000},"source":"Crossref","is-referenced-by-count":0,"title":["Fulminant Powassan Virus Encephalitis Presenting as Acute Ischemic Stroke: A Case Report"],"prefix":"10.56305","volume":"5","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-6938-6672","authenticated-orcid":true,"given":"Sushrut","family":"Ingawale","sequence":"first","affiliation":[{"name":"Quinnipiac University - Frank H. Netter, MD School of Medicine - St. Vincent\u2019s Medical Center, Bridgeport, Connecticut, United States","department":["Department of Internal Medicine"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yasheen","family":"Gao","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00mpz5a50","id-type":"ROR","asserted-by":"publisher"}],"name":"Quinnipiac University","department":["Department of Internal Medicine"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ishita","family":"Lanjewar","sequence":"additional","affiliation":[{"name":"Seth Gordhandas Sunderdas Medical College and King Edward Memorial Hospital, Mumbai, Maharashtra, India","department":["Department of Internal Medicine"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Latif","family":"Bashirov","sequence":"additional","affiliation":[{"name":"Quinnipiac University - Frank H. Netter, MD School of Medicine - St. Vincent\u2019s Medical Center, Bridgeport, Connecticut, United States","department":["Department of Radiology"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ian","family":"Guillen-Alvarez","sequence":"additional","affiliation":[{"name":"Department of Medicine, Quinnipiac University - Frank H. Netter, MD School of Medicine - St. Vincent\u2019s Medical Center, Bridgeport, Connecticut, United States.","department":["Department of Internal Medicine"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"David J.","family":"Regelmann","sequence":"additional","affiliation":[{"name":"Department of Medicine, Quinnipiac University - Frank H. Netter, MD School of Medicine - St. Vincent\u2019s Medical Center, Bridgeport, Connecticut, United States.","department":["Department of Internal Medicine"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"35509","published-online":{"date-parts":[[2026,7,1]]},"reference":[{"issue":"1","key":"ref1","doi-asserted-by":"publisher","DOI":"10.1128\/CMR.00106-17","article-title":"Tick-Borne Flaviviruses, with a Focus on Powassan Virus","volume":"32","author":"G. Kemenesi","year":"2019","journal-title":"Clin Microbiol Rev"},{"issue":"6","key":"ref2","doi-asserted-by":"publisher","first-page":"707","DOI":"10.1093\/cid\/civ1005","article-title":"Emerging Cases of Powassan Virus Encephalitis in New England: Clinical Presentation, Imaging, and Review of the Literature","volume":"62","author":"A. Piantadosi","year":"2016","journal-title":"Clin Infect Dis"},{"issue":"9","key":"ref3","doi-asserted-by":"publisher","first-page":"795","DOI":"10.47102\/annals-acadmedsg.V38N9p795","article-title":"Magnetic resonance imaging findings in bilateral basal ganglia lesions","volume":"38","author":"C. C. Lim","year":"2009","journal-title":"Ann Acad Med Singap"},{"key":"ref4","article-title":"Powassan Virus: Historic Data (2004-2024)"},{"issue":"1","key":"ref5","doi-asserted-by":"publisher","first-page":"2523887","DOI":"10.1080\/21505594.2025.2523887","article-title":"Pathogenicity and virulence of Powassan virus","volume":"16","author":"M. Kaur","year":"2025","journal-title":"Virulence"},{"key":"ref6","series-title":"StatPearls","article-title":"Powassan Virus","author":"A.K. Kapoor","year":"2025"},{"issue":"12","key":"ref7","doi-asserted-by":"publisher","DOI":"10.3390\/tropicalmed8120508","article-title":"Powassan Virus Infections: A Systematic Review of Published Cases","volume":"8","author":"L. Kakoullis","year":"2023","journal-title":"Trop Med Infect Dis"},{"issue":"6","key":"ref8","doi-asserted-by":"publisher","first-page":"746","DOI":"10.1001\/jamaneurol.2018.0132","article-title":"Fatal Powassan Encephalitis (Deer Tick Virus, Lineage II) in a Patient With Fever and Orchitis Receiving Rituximab","volume":"75","author":"I. H. Solomon","year":"2018","journal-title":"JAMA Neurol"},{"issue":"1","key":"ref9","doi-asserted-by":"publisher","first-page":"80","DOI":"10.1093\/cid\/ciad454","article-title":"Powassan Virus Encephalitis: A Tertiary Center Experience","volume":"78","author":"M. A. Mendoza","year":"2024","journal-title":"Clin Infect Dis"},{"issue":"6","key":"ref10","doi-asserted-by":"publisher","first-page":"1043","DOI":"10.1093\/cid\/cix435","article-title":"Fatal Deer Tick Virus Infection in Maine","volume":"65","author":"C. E. Cavanaugh","year":"2017","journal-title":"Clin Infect Dis"},{"issue":"10","key":"ref11","doi-asserted-by":"publisher","first-page":"143","DOI":"10.1038\/s41408-022-00737-y","article-title":"Fatal Powassan virus encephalitis in patients with chronic lymphocytic leukemia","volume":"12","author":"I. M. Johnson","year":"2022","journal-title":"Blood Cancer J"},{"issue":"6","key":"ref12","doi-asserted-by":"publisher","first-page":"707","DOI":"10.1093\/cid\/civ1005","article-title":"Emerging Cases of Powassan Virus Encephalitis in New England: Clinical Presentation, Imaging, and Review of the Literature","volume":"62","author":"A. Piantadosi","year":"2016","journal-title":"Clin Infect Dis"}],"container-title":["Journal of Brown Hospital Medicine"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/bhm.scholasticahq.com\/article\/162035-fulminant-powassan-virus-encephalitis-presenting-as-acute-ischemic-stroke-a-case-report","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,7,1]],"date-time":"2026-07-01T12:42:25Z","timestamp":1782909745000},"score":1,"resource":{"primary":{"URL":"https:\/\/bhm.scholasticahq.com\/article\/162035-fulminant-powassan-virus-encephalitis-presenting-as-acute-ischemic-stroke-a-case-report"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2026,7,1]]},"references-count":12,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2026]]}},"URL":"https:\/\/doi.org\/10.56305\/001c.162035","relation":{},"ISSN":["2994-5593"],"issn-type":[{"value":"2994-5593","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,7,1]]}}}