Paroxysmal bilateral involuntary movements without striatal imaging abnormalities in hyperglycemia-related metabolic encephalopathy after pancreatic resection: a case report

Paroxysmal bilateral involuntary movements without striatal imaging abnormalities in hyperglycemia-related metabolic encephalopathy after pancreatic resection: a case report | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Case Report Paroxysmal bilateral involuntary movements without striatal imaging abnormalities in hyperglycemia-related metabolic encephalopathy after pancreatic resection: a case report Rui Ban, Feng Liang, Di Wang, Jing Li, Xiaojing Fang, Li Wang This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9367463/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Background Hyperglycemia-related metabolic encephalopathy is an uncommon but clinically important neurological complication of diabetes. It most frequently presents as hemichorea–hemiballism associated with characteristic striatal abnormalities on neuroimaging. However, atypical presentations without imaging correlates remain underrecognized. Case presentation We report a 72-year-old woman with long-standing type 2 diabetes who developed paroxysmal involuntary movements involving the head, neck, and bilateral upper limbs following pancreatic tumor resection. The episodes were irregular, non-stereotyped, and occurred with preserved consciousness. Brain MRI revealed no acute lesions or characteristic striatal signal changes. Long-term video electroencephalography showed diffuse slow-wave activity without epileptiform discharges, effectively excluding an epileptic origin. Comprehensive cerebrospinal fluid and serological testing ruled out autoimmune and paraneoplastic etiologies. Notably, the patient exhibited marked glucose fluctuations during hospitalization rather than persistent severe hyperglycemia. The involuntary movements gradually resolved following stabilization of blood glucose levels. Conclusions This case expands the clinical spectrum of hyperglycemia-related movement disorders by demonstrating that they may present as paroxysmal, bilateral, and complex involuntary movements without typical imaging abnormalities. Postoperative metabolic instability following pancreatic resection may represent an important precipitating factor. Early recognition of this atypical phenotype is essential to avoid misdiagnosis and unnecessary interventions. Hyperglycemia metabolic encephalopathy involuntary movements diabetic striatopathy pancreatic resection glycemic variability Figures Figure 1 Figure 2 Figure 3 Background Hyperglycemia-related metabolic encephalopathy represents a reversible but often underrecognized neurological complication of diabetes mellitus. The most widely recognized manifestation is non-ketotic hyperglycemia-associated hemichorea–hemiballism, typically accompanied by hyperintensity in the contralateral striatum on T1-weighted magnetic resonance imaging (MRI) [ 1 – 4 ]. Recent evidence suggests that hyperglycemia-related movement disorders may encompass a broader clinical spectrum, including tremor, dystonia, and myoclonus, and may occur in the absence of characteristic imaging abnormalities [ 5 , 6 ]. These findings support the concept that diabetic striatopathy reflects a spectrum of metabolic dysfunction rather than a single clinicoradiological entity [ 6 ]. Furthermore, pancreatic resection can profoundly disrupt glucose homeostasis due to impaired insulin and glucagon regulation. Such postoperative metabolic instability may lead to significant glycemic variability, which may have important neurological consequences that remain poorly understood. Here, we describe an atypical case of hyperglycemia-related metabolic encephalopathy characterized by paroxysmal bilateral involuntary movements without striatal imaging abnormalities following pancreatic tumor resection. Although hyperglycemia-related movement disorders are well recognized, most reported cases present as unilateral hemichorea–hemiballism with characteristic striatal abnormalities on neuroimaging. In contrast, our patient exhibited paroxysmal bilateral involuntary movements involving the head, neck, and upper limbs, without typical imaging correlates, in the setting of postoperative pancreatic resection. This combination of features appears uncommon and further expands the recognized phenotype of hyperglycemia-related metabolic encephalopathy. Case Presentation A 72-year-old woman presented with a 3-day history of paroxysmal neck pain accompanied by involuntary movements involving the head, neck, and bilateral upper limbs. She had a 30-year history of type 2 diabetes mellitus with suboptimal glycemic control and had been receiving long-term insulin therapy. Her medical history was also significant for hypertension. In April 2023, she underwent partial pancreatectomy and splenectomy for pancreatic malignancy, without subsequent chemotherapy or radiotherapy. Additionally, she had essential thrombocythemia but had been irregularly treated with hydroxyurea. Three days prior to admission, she began experiencing episodic spasmodic neck pain lasting 1–2 minutes, initially occurring 4–5 times per hour. These episodes were subsequently followed by involuntary movements of the head and neck, which gradually progressed to involve both upper limbs. The frequency increased from approximately 10 episodes per day to several dozen per day, with each episode lasting from several seconds to 2 minutes. Importantly, the patient remained fully conscious and responsive throughout the episodes. There was no loss of consciousness, urinary incontinence, tongue biting, diplopia, dysarthria, or focal sensory loss during the attacks. Representative episodes of involuntary movements are shown in Additional file 1: Video 1 and Additional file 2: Video 2. Neurological examination revealed mild cognitive impairment, cerebellar ataxia (dysmetria on finger-to-nose and heel-to-shin testing), and mild proximal weakness of the lower limbs (Medical Research Council grade 4). No pathological reflexes or meningeal signs were observed. Laboratory investigations demonstrated fluctuating blood glucose levels, with fasting glucose ranging from 8.5 to 17.5 mmol/L and postprandial glucose ranging from 7.0 to 16.7 mmol/L. Glycated hemoglobin (HbA1c) was 7.9%. Cerebrospinal fluid analysis revealed elevated glucose levels without pleocytosis or evidence of infection or autoimmune pathology. Brain MRI showed chronic lacunar infarctions and white matter hyperintensities but no acute lesions or characteristic striatal T1 hyperintensity. Contrast-enhanced MRI demonstrated no abnormal enhancement. Brain MRI findings are shown in Fig. 1 . Cervical spine MRI demonstrated degenerative changes with multilevel intervertebral disc protrusions. Carotid ultrasonography revealed bilateral carotid intima–media thickening with atherosclerotic plaque formation. Chest CT showed interval improvement of a previous inflammatory lesion in the left lower lobe, with multiple stable pulmonary nodules and residual lesions. Abdominal CT demonstrated postoperative changes consistent with prior pancreatic resection, along with incidental findings including cholelithiasis and a probable right adrenal myelolipoma (Supplemental Fig. 1). Long-term video electroencephalography (15 hours) revealed diffuse slow-wave activity (1–3 Hz delta activity) without epileptiform discharges, including during recorded episodes, thereby excluding an epileptic origin. EEG findings are presented in Fig. 2 . Extensive investigations, including autoimmune encephalitis and paraneoplastic antibody panels, were negative. Based on the clinical features, exclusion of alternative etiologies, and the temporal relationship between symptom resolution and glycemic stabilization, a diagnosis of hyperglycemia-related metabolic encephalopathy with atypical involuntary movements was established. Following intensive glycemic control and supportive treatment, the frequency of involuntary movements progressively decreased and ultimately resolved. At 1-month follow-up, the patient remained symptom-free and functionally independent. Discussion This case illustrates an atypical presentation of hyperglycemia-related movement disorder, extending the clinical spectrum beyond classical diabetic striatopathy. To our knowledge, reports of hyperglycemia-related metabolic encephalopathy presenting with paroxysmal bilateral head-and-upper-limb involuntary movements without characteristic striatal imaging abnormalities, particularly in the setting of postoperative pancreatic resection, remain limited. Although the classical phenotype of hyperglycemia-related movement disorders is unilateral hemichorea–hemiballism associated with contralateral striatal abnormalities on CT or T1-weighted MRI [ 2 – 4 ], accumulating evidence suggests a broader and more heterogeneous clinical spectrum [ 5 , 6 ]. Imaging-negative cases have been reported, indicating that involuntary movements may occur even in the absence of detectable striatal abnormalities [ 6 ]. In addition, bilateral involvement, although distinctly uncommon, has also been described [ 5 ]. Facial and neck involvement may occur in some patients; however, these manifestations are typically considered extensions of a predominantly lateralized choreiform syndrome rather than the leading clinical presentation [ 3 , 4 ]. Against this background, our patient exhibited a distinctive combination of atypical features, including paroxysmal rather than continuous episodes, bilateral involvement of the head and upper limbs, preserved consciousness, absence of characteristic striatal imaging abnormalities, and occurrence in the setting of prior pancreatic resection. While atypical presentations have been reported, such cases remain limited and heterogeneous, and most previously described patients still demonstrate unilateral hemichorea–hemiballism with corresponding basal ganglia abnormalities on neuroimaging [ 2 – 4 , 6 ]. First, unlike typical cases, our patient did not exhibit characteristic striatal T1 hyperintensity. Previous studies have shown that T1 hyperintensity in the basal ganglia is a hallmark imaging feature but is not universally present, particularly in early or atypical cases [ 2 , 7 , 8 ]. This finding suggests that structural imaging abnormalities are not mandatory for diagnosis and that functional metabolic disturbances may precede detectable radiological changes. Second, the involuntary movements in this case were paroxysmal, bilateral, and predominantly involved the head and upper limbs, in contrast to the classical unilateral hemichorea–hemiballism described in most reports [ 3 , 4 ]. These features suggest that hyperglycemia-related neuronal dysfunction may not be confined to the basal ganglia, but could involve broader motor networks, including cerebellar and brainstem circuits. Furthermore, the preservation of consciousness during episodes, the non-stereotyped phenomenology, and the absence of ictal epileptiform discharges on prolonged video EEG monitoring strongly argue against an epileptic origin. Third, our findings suggest that glycemic variability, rather than sustained hyperglycemia alone, may play a critical role in pathogenesis. Although hyperosmolarity has been proposed as a contributing factor, our patient’s plasma osmolarity remained within the upper normal range. Instead, significant glucose fluctuations were observed, consistent with emerging evidence that metabolic instability may contribute to neuronal dysfunction [ 5 , 9 ]. Importantly, the history of pancreatic resection may have contributed significantly to the observed metabolic instability. Reduced β-cell reserve and impaired hormonal regulation following surgery may predispose patients to marked glycemic variability, thereby increasing vulnerability to metabolic neuronal dysfunction. The pathophysiological mechanisms underlying hyperglycemia-related movement disorders remain incompletely understood. Proposed mechanisms include depletion of gamma-aminobutyric acid (GABA), microvascular dysfunction, and regional metabolic suppression [ 7 , 10 – 12 ]. These processes may result in disinhibition of motor pathways and subsequent development of hyperkinetic movements. A schematic illustration of the hypothesized mechanism is shown in Fig. 3 . This case highlights the importance of considering metabolic etiologies in patients presenting with atypical involuntary movements, particularly when neuroimaging findings are unremarkable. The constellation of findings observed in this case—particularly paroxysmal bilateral head-and-upper-limb involvement without imaging correlates—broadens the recognized phenotype of hyperglycemia-related metabolic encephalopathy and suggests that postoperative glycemic instability may serve as a clinically relevant and underrecognized trigger. Early recognition of such atypical, imaging-negative presentations may help avoid misdiagnosis as epilepsy or functional movement disorders and prevent unnecessary treatments. Conclusion Hyperglycemia-related metabolic encephalopathy may present with atypical paroxysmal and bilateral involuntary movements in the absence of characteristic imaging findings. Postoperative metabolic instability following pancreatic resection may serve as an important precipitating factor. Early recognition and appropriate glycemic management are essential for favorable outcomes. Abbreviations CT Computed tomography CSF Cerebrospinal fluid EEG Electroencephalography FLAIR Fluid-attenuated inversion recovery GABA Gamma-aminobutyric acid HbA1c Glycated hemoglobin MRI Magnetic resonance imaging NKH-HC/HB Non-ketotic hyperglycemia-associated hemichorea–hemiballism Declarations Ethics approval and consent to participate This study was conducted in accordance with institutional ethical standards and the Declaration of Helsinki. Ethical approval for publication of this case report was waived by the local ethics committee because this is a single retrospective case report with no experimental intervention. Consent for publication Written informed consent for publication of this case report and the accompanying images/videos was obtained from the patient or the patient’s legal representative. Competing interests The authors declare that they have no competing interests. Funding No specific funding was received for this work. Author Contribution Rui Ban and Di Wang collected the clinical data and drafted the manuscript. Jing Li, Feng Liang and Xiaojing Fang interpreted the neuroimaging and VEEG findings. Li Wang revised the manuscript critically for important intellectual content. All authors read and approved the final manuscript. Acknowledgements Not applicable. Availability of data and materials All data generated or analyzed during this study are included in this published article and its supplementary information files. Further details are available from the corresponding author on reasonable request. References Bedwell SF. Some observations on hemiballismus. Neurology. 1960;10:619–22. Oh SH, Lee KY, Im JH, et al. Chorea associated with non-ketotic hyperglycemia and hyperintensity basal ganglia lesion on T1-weighted brain MRI study: a meta-analysis of 53 cases including four present cases. J Neurol Sci. 2002;200(1–2):57–62. Cosentino C, Torres L, Nuñez Y et al. Hemichorea/hemiballism associated with hyperglycemia: report of 20 cases. Tremor Other Hyperkinet Mov (N Y). 2016;6:402. Postuma RB, Lang AE. Hemiballism: revisiting a classic disorder. Lancet Neurol. 2003;2(11):661–8. Chang CV, Felicio AC, Godeiro Cde O Jr, et al. Chorea-ballism as a manifestation of decompensated type 2 diabetes mellitus. Am J Med Sci. 2007;333(3):175–7. Chua CB, Sun CK, Hsu CW, et al. Diabetic striatopathy: clinical presentations, controversy, pathogenesis, treatments, and outcomes. Sci Rep. 2020;10(1):1594. Shan DE, Ho DM, Chang C, et al. Hemichorea-hemiballism: an explanation for MR signal changes. AJNR Am J Neuroradiol. 1998;19(5):863–70. Lee EJ, Choi JY, Lee SH, et al. Hemichorea-hemiballism in primary diabetic patients: MR correlation. J Comput Assist Tomogr. 2002;26(6):905–11. Ranjan A, Mudassir S, Sinha N, et al. Diabetic striatopathy: a case series of rare and treatable movement disorder. Ann Mov Disord. 2023;6:26–9. Robottom BJ, Factor SA, Weiner WJ. Movement disorders emergencies part 2: hyperkinetic disorders. Arch Neurol. 2011;68(6):719–24. Abe Y, Yamamoto T, Soeda T, et al. Diabetic striatal disease: clinical presentation, neuroimaging, and pathology. Intern Med. 2009;48(13):1135–41. Hsu JL, Wang HC, Hsu WC. Hyperglycemia-induced unilateral basal ganglion lesions with and without hemichorea: a PET study. J Neurol. 2004;251(12):1486–90. Additional Declarations No competing interests reported. Supplementary Files supplPicture1.jpg Supplemental Figure 1. Abdominal CT findings following pancreatic tumor resection. Contrast-enhanced abdominal CT images (A–B) demonstrate postoperative changes consistent with partial pancreatic resection, with altered pancreatic morphology and residual pancreatic tissue (arrows). No evidence of tumor recurrence is observed. video1.mp4 Supplemental Video 1. Paroxysmal involuntary movements of the right upper limb. During an episode, the patient, while seated on the bed, developed prominent involuntary movements of the right upper limb. These were characterized by rapid, irregular shaking and large-amplitude flinging movements, with non-rhythmic finger flexion–extension and rotational movements of the forearm resembling ballistic activity. Consciousness was fully preserved, and the left upper limb remained relatively stable. video2.mp4 Supplemental Video 2. Combined head and bilateral upper limb involuntary movements. During episodes occurring prior to meals or medication intake, the patient developed abrupt, non-rhythmic head tremor and involuntary oscillatory movements, accompanied by frequent, irregular shaking and grasping-like movements of both upper limbs, more prominent on the right side. These complex paroxysmal movements were temporally associated with the patient’s reported spasmodic neck pain. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9367463","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Case Report","associatedPublications":[],"authors":[{"id":634413478,"identity":"28c280a0-ce60-497f-9474-8f9c6bcca72c","order_by":0,"name":"Rui Ban","email":"","orcid":"","institution":"The First Hospital of Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Rui","middleName":"","lastName":"Ban","suffix":""},{"id":634413479,"identity":"e4c4cbf2-89d0-43bf-b6e3-4686bfa02126","order_by":1,"name":"Feng Liang","email":"","orcid":"","institution":"The First Hospital of Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Feng","middleName":"","lastName":"Liang","suffix":""},{"id":634413480,"identity":"1e8e4f00-adc4-4be3-8c6f-6ded03315ba2","order_by":2,"name":"Di Wang","email":"","orcid":"","institution":"The First Hospital of Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Di","middleName":"","lastName":"Wang","suffix":""},{"id":634413481,"identity":"0577653f-666f-491c-af01-2b5bb367595f","order_by":3,"name":"Jing Li","email":"","orcid":"","institution":"The First Hospital of Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Jing","middleName":"","lastName":"Li","suffix":""},{"id":634413482,"identity":"983d0e91-717d-403a-a3aa-d4b1c07a8797","order_by":4,"name":"Xiaojing Fang","email":"","orcid":"","institution":"The First Hospital of Tsinghua University","correspondingAuthor":false,"prefix":"","firstName":"Xiaojing","middleName":"","lastName":"Fang","suffix":""},{"id":634413483,"identity":"be12b7f4-ae61-4b50-8593-eafa66e52457","order_by":5,"name":"Li Wang","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAzklEQVRIiWNgGAWjYBACgxuMDYd/GNjI2bc3MBwgUgvzwccMFWnGBjwHiNbClmzMcOZQ4gaJBKIdxmMmXdh2wNhc8vnDwwU1DPL8YgQsMwNpmdl2R85ydo7B4RnHGAxnziZgHUiLBG/bM2OG2zkMh3nYGBIMbhOn5XBiw83jDw7z/CNCiz3I+zxnDiduuMFgcJi3jQgtlsBAfjgDGMiSPUC/8PZJEPaLwf2DDQc+AKOSn/34488832zk+aUJaEEHEqQpHwWjYBSMglGAHQAAUQxMUXXZpoYAAAAASUVORK5CYII=","orcid":"","institution":"The First Hospital of Tsinghua University","correspondingAuthor":true,"prefix":"","firstName":"Li","middleName":"","lastName":"Wang","suffix":""}],"badges":[],"createdAt":"2026-04-09 10:53:56","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9367463/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9367463/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":108836868,"identity":"cf635dff-ad01-492d-8370-61f1a217a096","added_by":"auto","created_at":"2026-05-09 00:01:44","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":342482,"visible":true,"origin":"","legend":"\u003cp\u003eBrain MRI findings. Axial T1-weighted images show symmetrical signal intensity in the bilateral basal ganglia without abnormal hyperintensity (A). T2-weighted and FLAIR images demonstrate no abnormal signal changes in the basal ganglia (B–C). Diffusion-weighted imaging reveals no restricted diffusion, excluding acute ischemic lesions (D). Contrast-enhanced T1-weighted images in both coronal and axial planes show no abnormal enhancement in the basal ganglia, thalamus, or brainstem (E–F). Notably, no characteristic striatal T1 hyperintensity is observed, which is typically reported in non-ketotic hyperglycemia-related hemichorea–hemiballism.\u003c/p\u003e","description":"","filename":"Picture1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9367463/v1/7c61935d3333c6d25b03a287.jpg"},{"id":108977782,"identity":"9f148e76-9d9d-4a5b-8e19-b25c52792f1d","added_by":"auto","created_at":"2026-05-11 11:32:52","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":399096,"visible":true,"origin":"","legend":"\u003cp\u003eVideo electroencephalography findings. Long-term video EEG monitoring demonstrates diffuse slow-wave activity (1–3 Hz delta waves) without epileptiform discharges during the recorded episodes, supporting a non-epileptic origin of the involuntary movements.\u003c/p\u003e","description":"","filename":"Picture2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9367463/v1/4a5e145341a1203b696e8c56.jpg"},{"id":109067546,"identity":"7c17c9b9-8039-45b9-aea5-80a42c6199c5","added_by":"auto","created_at":"2026-05-12 09:55:41","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":636164,"visible":true,"origin":"","legend":"\u003cp\u003eHypothesized pathophysiological mechanism. Schematic illustration of a possible mechanism linking pancreatic resection to glycemic instability. Reduced β-cell reserve and impaired insulin/glucagon regulation may increase glycemic variability, which in turn may contribute to metabolic dysfunction of motor control networks, including basal ganglia and cerebellar circuits, ultimately leading to involuntary movements.\u003c/p\u003e","description":"","filename":"Picture3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9367463/v1/160343d306a25fa2b9d7ec83.jpg"},{"id":109252431,"identity":"7e396932-7dd5-4385-83ca-0fef99c2d830","added_by":"auto","created_at":"2026-05-14 09:26:17","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":1505164,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9367463/v1/98421421-e621-43ed-b5ad-c6943c10828d.pdf"},{"id":108836870,"identity":"3dbe8c5c-9bfa-4c79-a69a-8e2829f01406","added_by":"auto","created_at":"2026-05-09 00:01:44","extension":"jpg","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":134842,"visible":true,"origin":"","legend":"\u003cp\u003eSupplemental Figure 1. Abdominal CT findings following pancreatic tumor resection.\u003c/p\u003e\n\u003cp\u003eContrast-enhanced abdominal CT images (A–B) demonstrate postoperative changes consistent with partial pancreatic resection, with altered pancreatic morphology and residual pancreatic tissue (arrows). No evidence of tumor recurrence is observed.\u003c/p\u003e","description":"","filename":"supplPicture1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-9367463/v1/5e8d783bcc239cf8c7172ed4.jpg"},{"id":109203558,"identity":"feac87c4-3450-4d32-bf1d-041619e29c40","added_by":"auto","created_at":"2026-05-13 14:38:50","extension":"mp4","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":11621608,"visible":true,"origin":"","legend":"\u003cp\u003eSupplemental Video 1. Paroxysmal involuntary movements of the right upper limb.\u003c/p\u003e\n\u003cp\u003eDuring an episode, the patient, while seated on the bed, developed prominent involuntary movements of the right upper limb. These were characterized by rapid, irregular shaking and large-amplitude flinging movements, with non-rhythmic finger flexion–extension and rotational movements of the forearm resembling ballistic activity. Consciousness was fully preserved, and the left upper limb remained relatively stable.\u003c/p\u003e","description":"","filename":"video1.mp4","url":"https://assets-eu.researchsquare.com/files/rs-9367463/v1/cd81f357e7c06f1f977381ea.mp4"},{"id":108977119,"identity":"0892c75e-a1e0-4529-944d-7d0f3ccd6ee0","added_by":"auto","created_at":"2026-05-11 11:30:27","extension":"mp4","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":4690293,"visible":true,"origin":"","legend":"\u003cp\u003eSupplemental \u0026nbsp;Video 2. Combined head and bilateral upper limb involuntary movements.\u003c/p\u003e\n\u003cp\u003eDuring episodes occurring prior to meals or medication intake, the patient developed abrupt, non-rhythmic head tremor and involuntary oscillatory movements, accompanied by frequent, irregular shaking and grasping-like movements of both upper limbs, more prominent on the right side. These complex paroxysmal movements were temporally associated with the patient’s reported spasmodic neck pain.\u003c/p\u003e","description":"","filename":"video2.mp4","url":"https://assets-eu.researchsquare.com/files/rs-9367463/v1/4cd2f0425ebd8058a8b034e0.mp4"}],"financialInterests":"No competing interests reported.","formattedTitle":"Paroxysmal bilateral involuntary movements without striatal imaging abnormalities in hyperglycemia-related metabolic encephalopathy after pancreatic resection: a case report","fulltext":[{"header":"Background","content":"\u003cp\u003eHyperglycemia-related metabolic encephalopathy represents a reversible but often underrecognized neurological complication of diabetes mellitus. The most widely recognized manifestation is non-ketotic hyperglycemia-associated hemichorea\u0026ndash;hemiballism, typically accompanied by hyperintensity in the contralateral striatum on T1-weighted magnetic resonance imaging (MRI) [\u003cspan additionalcitationids=\"CR2 CR3\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eRecent evidence suggests that hyperglycemia-related movement disorders may encompass a broader clinical spectrum, including tremor, dystonia, and myoclonus, and may occur in the absence of characteristic imaging abnormalities [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. These findings support the concept that diabetic striatopathy reflects a spectrum of metabolic dysfunction rather than a single clinicoradiological entity [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFurthermore, pancreatic resection can profoundly disrupt glucose homeostasis due to impaired insulin and glucagon regulation. Such postoperative metabolic instability may lead to significant glycemic variability, which may have important neurological consequences that remain poorly understood.\u003c/p\u003e \u003cp\u003eHere, we describe an atypical case of hyperglycemia-related metabolic encephalopathy characterized by paroxysmal bilateral involuntary movements without striatal imaging abnormalities following pancreatic tumor resection. Although hyperglycemia-related movement disorders are well recognized, most reported cases present as unilateral hemichorea\u0026ndash;hemiballism with characteristic striatal abnormalities on neuroimaging. In contrast, our patient exhibited paroxysmal bilateral involuntary movements involving the head, neck, and upper limbs, without typical imaging correlates, in the setting of postoperative pancreatic resection. This combination of features appears uncommon and further expands the recognized phenotype of hyperglycemia-related metabolic encephalopathy.\u003c/p\u003e"},{"header":"Case Presentation","content":"\u003cp\u003eA 72-year-old woman presented with a 3-day history of paroxysmal neck pain accompanied by involuntary movements involving the head, neck, and bilateral upper limbs. She had a 30-year history of type 2 diabetes mellitus with suboptimal glycemic control and had been receiving long-term insulin therapy. Her medical history was also significant for hypertension. In April 2023, she underwent partial pancreatectomy and splenectomy for pancreatic malignancy, without subsequent chemotherapy or radiotherapy. Additionally, she had essential thrombocythemia but had been irregularly treated with hydroxyurea.\u003c/p\u003e \u003cp\u003eThree days prior to admission, she began experiencing episodic spasmodic neck pain lasting 1\u0026ndash;2 minutes, initially occurring 4\u0026ndash;5 times per hour. These episodes were subsequently followed by involuntary movements of the head and neck, which gradually progressed to involve both upper limbs. The frequency increased from approximately 10 episodes per day to several dozen per day, with each episode lasting from several seconds to 2 minutes. Importantly, the patient remained fully conscious and responsive throughout the episodes. There was no loss of consciousness, urinary incontinence, tongue biting, diplopia, dysarthria, or focal sensory loss during the attacks. Representative episodes of involuntary movements are shown in Additional file 1: Video 1 and Additional file 2: Video 2.\u003c/p\u003e \u003cp\u003eNeurological examination revealed mild cognitive impairment, cerebellar ataxia (dysmetria on finger-to-nose and heel-to-shin testing), and mild proximal weakness of the lower limbs (Medical Research Council grade 4). No pathological reflexes or meningeal signs were observed. Laboratory investigations demonstrated fluctuating blood glucose levels, with fasting glucose ranging from 8.5 to 17.5 mmol/L and postprandial glucose ranging from 7.0 to 16.7 mmol/L. Glycated hemoglobin (HbA1c) was 7.9%. Cerebrospinal fluid analysis revealed elevated glucose levels without pleocytosis or evidence of infection or autoimmune pathology. Brain MRI showed chronic lacunar infarctions and white matter hyperintensities but no acute lesions or characteristic striatal T1 hyperintensity. Contrast-enhanced MRI demonstrated no abnormal enhancement. Brain MRI findings are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Cervical spine MRI demonstrated degenerative changes with multilevel intervertebral disc protrusions. Carotid ultrasonography revealed bilateral carotid intima\u0026ndash;media thickening with atherosclerotic plaque formation. Chest CT showed interval improvement of a previous inflammatory lesion in the left lower lobe, with multiple stable pulmonary nodules and residual lesions. Abdominal CT demonstrated postoperative changes consistent with prior pancreatic resection, along with incidental findings including cholelithiasis and a probable right adrenal myelolipoma (Supplemental Fig.\u0026nbsp;1). Long-term video electroencephalography (15 hours) revealed diffuse slow-wave activity (1\u0026ndash;3 Hz delta activity) without epileptiform discharges, including during recorded episodes, thereby excluding an epileptic origin. EEG findings are presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e. Extensive investigations, including autoimmune encephalitis and paraneoplastic antibody panels, were negative.\u003c/p\u003e \u003cp\u003eBased on the clinical features, exclusion of alternative etiologies, and the temporal relationship between symptom resolution and glycemic stabilization, a diagnosis of hyperglycemia-related metabolic encephalopathy with atypical involuntary movements was established.\u003c/p\u003e \u003cp\u003eFollowing intensive glycemic control and supportive treatment, the frequency of involuntary movements progressively decreased and ultimately resolved. At 1-month follow-up, the patient remained symptom-free and functionally independent.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eThis case illustrates an atypical presentation of hyperglycemia-related movement disorder, extending the clinical spectrum beyond classical diabetic striatopathy. To our knowledge, reports of hyperglycemia-related metabolic encephalopathy presenting with paroxysmal bilateral head-and-upper-limb involuntary movements without characteristic striatal imaging abnormalities, particularly in the setting of postoperative pancreatic resection, remain limited.\u003c/p\u003e \u003cp\u003eAlthough the classical phenotype of hyperglycemia-related movement disorders is unilateral hemichorea\u0026ndash;hemiballism associated with contralateral striatal abnormalities on CT or T1-weighted MRI [\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e], accumulating evidence suggests a broader and more heterogeneous clinical spectrum [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Imaging-negative cases have been reported, indicating that involuntary movements may occur even in the absence of detectable striatal abnormalities [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In addition, bilateral involvement, although distinctly uncommon, has also been described [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. Facial and neck involvement may occur in some patients; however, these manifestations are typically considered extensions of a predominantly lateralized choreiform syndrome rather than the leading clinical presentation [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAgainst this background, our patient exhibited a distinctive combination of atypical features, including paroxysmal rather than continuous episodes, bilateral involvement of the head and upper limbs, preserved consciousness, absence of characteristic striatal imaging abnormalities, and occurrence in the setting of prior pancreatic resection. While atypical presentations have been reported, such cases remain limited and heterogeneous, and most previously described patients still demonstrate unilateral hemichorea\u0026ndash;hemiballism with corresponding basal ganglia abnormalities on neuroimaging [\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eFirst, unlike typical cases, our patient did not exhibit characteristic striatal T1 hyperintensity. Previous studies have shown that T1 hyperintensity in the basal ganglia is a hallmark imaging feature but is not universally present, particularly in early or atypical cases [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. This finding suggests that structural imaging abnormalities are not mandatory for diagnosis and that functional metabolic disturbances may precede detectable radiological changes.\u003c/p\u003e \u003cp\u003eSecond, the involuntary movements in this case were paroxysmal, bilateral, and predominantly involved the head and upper limbs, in contrast to the classical unilateral hemichorea\u0026ndash;hemiballism described in most reports [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. These features suggest that hyperglycemia-related neuronal dysfunction may not be confined to the basal ganglia, but could involve broader motor networks, including cerebellar and brainstem circuits. Furthermore, the preservation of consciousness during episodes, the non-stereotyped phenomenology, and the absence of ictal epileptiform discharges on prolonged video EEG monitoring strongly argue against an epileptic origin.\u003c/p\u003e \u003cp\u003eThird, our findings suggest that glycemic variability, rather than sustained hyperglycemia alone, may play a critical role in pathogenesis. Although hyperosmolarity has been proposed as a contributing factor, our patient\u0026rsquo;s plasma osmolarity remained within the upper normal range. Instead, significant glucose fluctuations were observed, consistent with emerging evidence that metabolic instability may contribute to neuronal dysfunction [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eImportantly, the history of pancreatic resection may have contributed significantly to the observed metabolic instability. Reduced β-cell reserve and impaired hormonal regulation following surgery may predispose patients to marked glycemic variability, thereby increasing vulnerability to metabolic neuronal dysfunction.\u003c/p\u003e \u003cp\u003eThe pathophysiological mechanisms underlying hyperglycemia-related movement disorders remain incompletely understood. Proposed mechanisms include depletion of gamma-aminobutyric acid (GABA), microvascular dysfunction, and regional metabolic suppression [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan additionalcitationids=\"CR11\" citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. These processes may result in disinhibition of motor pathways and subsequent development of hyperkinetic movements. A schematic illustration of the hypothesized mechanism is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e.\u003c/p\u003e \u003cp\u003eThis case highlights the importance of considering metabolic etiologies in patients presenting with atypical involuntary movements, particularly when neuroimaging findings are unremarkable. The constellation of findings observed in this case\u0026mdash;particularly paroxysmal bilateral head-and-upper-limb involvement without imaging correlates\u0026mdash;broadens the recognized phenotype of hyperglycemia-related metabolic encephalopathy and suggests that postoperative glycemic instability may serve as a clinically relevant and underrecognized trigger. Early recognition of such atypical, imaging-negative presentations may help avoid misdiagnosis as epilepsy or functional movement disorders and prevent unnecessary treatments.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eHyperglycemia-related metabolic encephalopathy may present with atypical paroxysmal and bilateral involuntary movements in the absence of characteristic imaging findings. Postoperative metabolic instability following pancreatic resection may serve as an important precipitating factor. Early recognition and appropriate glycemic management are essential for favorable outcomes.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCT\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eComputed tomography\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eCSF\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eCerebrospinal fluid\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eEEG\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eElectroencephalography\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eFLAIR\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eFluid-attenuated inversion recovery\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eGABA\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eGamma-aminobutyric acid\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eHbA1c\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eGlycated hemoglobin\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eMRI\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eMagnetic resonance imaging\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eNKH-HC/HB\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eNon-ketotic hyperglycemia-associated hemichorea\u0026ndash;hemiballism\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":" \u003cp\u003e \u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e \u003cp\u003eThis study was conducted in accordance with institutional ethical standards and the Declaration of Helsinki. Ethical approval for publication of this case report was waived by the local ethics committee because this is a single retrospective case report with no experimental intervention.\u003c/p\u003e \u003c/p\u003e \u003cp\u003e \u003cstrong\u003eConsent for publication\u003c/strong\u003e \u003cp\u003e Written informed consent for publication of this case report and the accompanying images/videos was obtained from the patient or the patient\u0026rsquo;s legal representative.\u003c/p\u003e \u003c/p\u003e\u003cp\u003e \u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e \u003cp\u003eNo specific funding was received for this work.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eRui Ban and Di Wang collected the clinical data and drafted the manuscript. Jing Li, Feng Liang and Xiaojing Fang interpreted the neuroimaging and VEEG findings. Li Wang revised the manuscript critically for important intellectual content. All authors read and approved the final manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e \u003cp\u003eNot applicable.\u003c/p\u003e\u003ch2\u003eAvailability of data and materials\u003c/h2\u003e \u003cp\u003eAll data generated or analyzed during this study are included in this published article and its supplementary information files. Further details are available from the corresponding author on reasonable request.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eBedwell SF. Some observations on hemiballismus. Neurology. 1960;10:619\u0026ndash;22.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eOh SH, Lee KY, Im JH, et al. Chorea associated with non-ketotic hyperglycemia and hyperintensity basal ganglia lesion on T1-weighted brain MRI study: a meta-analysis of 53 cases including four present cases. J Neurol Sci. 2002;200(1\u0026ndash;2):57\u0026ndash;62.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCosentino C, Torres L, Nu\u0026ntilde;ez Y et al. Hemichorea/hemiballism associated with hyperglycemia: report of 20 cases. Tremor Other Hyperkinet Mov (N Y). 2016;6:402.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePostuma RB, Lang AE. Hemiballism: revisiting a classic disorder. Lancet Neurol. 2003;2(11):661\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChang CV, Felicio AC, Godeiro Cde O Jr, et al. Chorea-ballism as a manifestation of decompensated type 2 diabetes mellitus. Am J Med Sci. 2007;333(3):175\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChua CB, Sun CK, Hsu CW, et al. Diabetic striatopathy: clinical presentations, controversy, pathogenesis, treatments, and outcomes. Sci Rep. 2020;10(1):1594.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShan DE, Ho DM, Chang C, et al. Hemichorea-hemiballism: an explanation for MR signal changes. AJNR Am J Neuroradiol. 1998;19(5):863\u0026ndash;70.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLee EJ, Choi JY, Lee SH, et al. Hemichorea-hemiballism in primary diabetic patients: MR correlation. J Comput Assist Tomogr. 2002;26(6):905\u0026ndash;11.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRanjan A, Mudassir S, Sinha N, et al. Diabetic striatopathy: a case series of rare and treatable movement disorder. Ann Mov Disord. 2023;6:26\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRobottom BJ, Factor SA, Weiner WJ. Movement disorders emergencies part 2: hyperkinetic disorders. Arch Neurol. 2011;68(6):719\u0026ndash;24.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbe Y, Yamamoto T, Soeda T, et al. Diabetic striatal disease: clinical presentation, neuroimaging, and pathology. Intern Med. 2009;48(13):1135\u0026ndash;41.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHsu JL, Wang HC, Hsu WC. Hyperglycemia-induced unilateral basal ganglion lesions with and without hemichorea: a PET study. J Neurol. 2004;251(12):1486\u0026ndash;90.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Hyperglycemia, metabolic encephalopathy, involuntary movements, diabetic striatopathy, pancreatic resection, glycemic variability","lastPublishedDoi":"10.21203/rs.3.rs-9367463/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9367463/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eBackground\u003c/p\u003e\n\u003cp\u003eHyperglycemia-related metabolic encephalopathy is an uncommon but clinically important neurological complication of diabetes. It most frequently presents as hemichorea–hemiballism associated with characteristic striatal abnormalities on neuroimaging. However, atypical presentations without imaging correlates remain underrecognized.\u003c/p\u003e\n\u003cp\u003eCase presentation\u003c/p\u003e\n\u003cp\u003eWe report a 72-year-old woman with long-standing type 2 diabetes who developed paroxysmal involuntary movements involving the head, neck, and bilateral upper limbs following pancreatic tumor resection. The episodes were irregular, non-stereotyped, and occurred with preserved consciousness. Brain MRI revealed no acute lesions or characteristic striatal signal changes. Long-term video electroencephalography showed diffuse slow-wave activity without epileptiform discharges, effectively excluding an epileptic origin. Comprehensive cerebrospinal fluid and serological testing ruled out autoimmune and paraneoplastic etiologies. Notably, the patient exhibited marked glucose fluctuations during hospitalization rather than persistent severe hyperglycemia. The involuntary movements gradually resolved following stabilization of blood glucose levels.\u003c/p\u003e\n\u003cp\u003eConclusions\u003c/p\u003e\n\u003cp\u003eThis case expands the clinical spectrum of hyperglycemia-related movement disorders by demonstrating that they may present as paroxysmal, bilateral, and complex involuntary movements without typical imaging abnormalities. Postoperative metabolic instability following pancreatic resection may represent an important precipitating factor. Early recognition of this atypical phenotype is essential to avoid misdiagnosis and unnecessary interventions.\u003c/p\u003e","manuscriptTitle":"Paroxysmal bilateral involuntary movements without striatal imaging abnormalities in hyperglycemia-related metabolic encephalopathy after pancreatic resection: a case report","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-05-09 00:01:38","doi":"10.21203/rs.3.rs-9367463/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"02c240c0-7fd7-4810-9fd3-88193872fa5d","owner":[],"postedDate":"May 9th, 2026","published":true,"recentEditorialEvents":[{"type":"decision","content":"Rejected","date":"2026-05-05T03:09:51+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2026-05-02T18:10:11+00:00","index":32,"fulltext":""},{"type":"reviewerAgreed","content":"324171330687135303728934138757601881485","date":"2026-05-02T11:38:02+00:00","index":31,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-05-11T11:26:17+00:00","versionOfRecord":[],"versionCreatedAt":"2026-05-09 00:01:38","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9367463","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9367463","identity":"rs-9367463","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}