Isolated Bell's Palsy Associated with Ustekinumab in Crohn's Disease: Clinical Case and Review of Neurological Safety

Isolated Bell's Palsy Associated with Ustekinumab in Crohn's Disease: Clinical Case and Review of Neurological Safety | 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 Isolated Bell's Palsy Associated with Ustekinumab in Crohn's Disease: Clinical Case and Review of Neurological Safety Khyathi Thalamanchi, Pardhu Bharath Neelam This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8307283/v1 This work is licensed under a CC BY 4.0 License Status: Under Revision Version 1 posted 4 You are reading this latest preprint version Abstract Ustekinumab is widely used in Crohn’s disease with a favourable safety profile, and neurological adverse events are rarely reported. We report a 58-year-old man with perianal fistulising Crohn’s disease who developed acute isolated lower motor neuron facial nerve palsy one week after sixth maintenance dose of ustekinumab. Extensive evaluation excluded infectious, autoimmune, structural, and otolaryngological causes. Ustekinumab was withheld, and the patient was treated conservatively with steroids and antivirals, with complete recovery over 12 weeks. This case highlights Bell’s palsy as a rare neurological adverse event temporally associated with ustekinumab and underscores the need for vigilance and continued post-marketing surveillance. Crohn’s disease Ustekinumab Bell’s palsy Neurological adverse events Biologic therapy Figures Figure 1 Introduction Bell’s palsy, an acute lower motor neuron facial nerve palsy, most commonly idiopathic, although associations with viral reactivation, immune dysregulation, and immunosuppressive states have been described. ( 1 ) In inflammatory bowel disease (IBD), biologic therapies have occasionally been implicated in neurological adverse events, particularly anti-TNF agents. ( 2 ) Ustekinumab, an interleukin-12/23 inhibitor, has a favourable safety profile, with neurological complications reported infrequently. We report a case of Bell’s palsy temporally associated with ustekinumab therapy in a patient with Crohn’s Disease (CD). Case report A 58-year-old man with a 34-month history of CD involving the colon with perianal fistulas, complicated by an anorectal stricture, now presented with an acute right-sided facial droop. ( Fig. 1 ) The patient was initially treated with infliximab in combination with azathioprine, achieving an initial clinical response. After the eighth dose of infliximab, he developed secondary loss of response, and was positive for anti-infliximab antibodies. Given persistent active perianal disease with discharge, he was initiated on ustekinumab. He had received a 520 mg intravenous induction dose, and was on 90 mg subcutaneous maintenance dosing every 8 weekly. The first five maintenance doses were well tolerated with improvement in disease activity in the form of reduced perianal discharge. A week after the sixth subcutaneous ustekinumab dose, the patient developed acute right-sided facial nerve palsy, characterized by inability to close the right eye and deviation of the mouth toward the left. On examination, vital signs were normal, and neurological examination revealed isolated right lower motor neuron facial nerve palsy. Magnetic resonance imaging of the brain showed no structural or demyelinating lesions. Cerebrospinal fluid analysis was normal. Serological testing for herpes simplex virus and varicella-zoster virus was negative, as was antinuclear antibody testing. Otolaryngology evaluation excluded structural pathology involving the facial nerve within the fallopian canal. In view of the temporal relationship with ustekinumab exposure and exclusion of alternative aetiologies, a decision was made to withhold ustekinumab. The patient was initiated on short course of steroids and antiviral (acyclovir) by the neurology team. He was under close follow-up, showed a complete resolution at 12 weeks. The patient provided written informed consent for publication of this case report and any accompanying images. Discussion IBD is known to be associated with an increased risk of several neurological disorders, particularly demyelinating diseases. Population based cohort studies have demonstrated an increased hazard of multiple sclerosis (MS) following a diagnosis of IBD in patients with UC and CD at 2.35 (95% CI: 1.47–3.78) and 2.09 (95% CI: 1.28–3.39) respectively. ( 3 ) However, when demyelinating disorders (MS, Demyelination and Optic Neuritis) are analysed collectively, the overall risk in CD appears less consistent (IRR − 2.12, 95% CI: 0.94–4.50) and is also not clearly associated with disease activity or concomitant immunosuppressive therapy.( 4 ) Ustekinumab, a monoclonal antibody targeting the p40 subunit of interleukin-12 (IL-12) and interleukin-23 (IL-23), is an established therapy for moderate-to-severe CD, including perianal phenotypes with an overall favourable safety profile. ( 5 ) In contrast to other biologics like anti-TNF, no major neurological complications like demyelination was reported in the FAERS-based safety analysis of ustekinumab in CD. ( 6 ) Another pooled analyses of ustekinumab trials in IBD which included 2575 patients and 4826 patient-years of follow-up reported no severe neurological complications or demyelinating disorders. ( 7 ) To date, only isolated case reports of severe neurological adverse events associated with ustekinumab have been published, including posterior reversible encephalopathy syndrome (PRES), central and peripheral demyelinating disorders, and a single report of Bell’s palsy in ulcerative colitis.( 8 – 12 ) The key published cases in IBD are summarized in Table 1 . Table 1 Severe Neurological events associated with Ustekinumab therapy in IBD Author / Year Type of IBD Drug History Ustekinumab Regimen Neurological Event Time to Onset Diagnostic Findings Management Outcome Mishra & Seril, 2018 ( 8 ) CD - A1 B2/3P L3 Mesalamine, 6-MP, methotrexate, infliximab 340 mg IV induction PRES with seizures 12 days post-induction MRI: bilateral frontal, parietal, occipital T2/FLAIR hyperintensities Stopped Ustekinumab. Antiepileptics Full recovery, MRI resolution CD - A3 B2P L3 Mesalamine, ciprofloxacin, prednisone, thalidomide, infliximab, adalimumab 390 mg IV induction Acute encephalopathy, atypical PRES 6 days post-induction MRI/MRA: scattered periventricular & subcortical T2/FLAIR signals Stopped Ustekinumab. Recovery with mild residual headache. Jordan & Kinnucan, 2022 ( 9 ) CD - A3 B3P L3 Adalimumab for 25 yrs 90 mg SC every 8 weeks maintenance for 2.5 yrs PRES with headache, weakness, urinary incontinence 2 months after last dose in maintenance phase MRI: multifocal T2/FLAIR hyperintensities in cerebellum, posterior fossa Stopped Ustekinumab. Switched to vedolizumab. Antihypertensives. Partial recovery. Persistent hypertension & gait difficulty Badat et al. 2014 ( 10 ) CD - A2 B2 L1 Azathioprine, methotrexate, infliximab, adalimumab, certolizumab 90 mg SC every 12 weekly Central demyelination, Primary progressive MS At 1 year after exposure MRI: multiple periventricular & juxtacortical lesions; spinal cord lesion. CSF: normal Continued ustekinumab. Mycophenolate. Persistent neurological deficits. CD in sustained clinical response. Honap et al. 2023 ( 11 ) UC - E2 Adalimumab (prior demyelination), vedolizumab IV induction followed by SC maintenance Sub-acute inflammatory demyelinating polyneuropathy (SIDP) 5 days post-induction EMG/NCS: peripheral demyelination. CSF: protein elevated. MRI: normal Stopped Ustekinumab. IV Immunoglobulins given. Significant recovery. Petrou A 2024 ( 12 ) UC sulfasalazine and mesalamine Ustekinumab therapy (induction phase) Bell’s palsy (CN VII palsy) 2 week after 1st dose Clinical exam: LMN facial nerve palsy. Brain Imaging: Normal Continued Ustekinumab. Short course of steroid and antivirals. Full recovery CD – Crohn’s disease, CSF – Cerebrospinal fluid, EMG – Electromyography, IV – Intravenous, MRI – Magnetic Resonance Imaging, NCS – Nerve conduction studies, SC -Subcutaneous, UC – ulcerative colitis. Bell’s palsy, although common in the general population, has been only rarely described in association with biologic therapy, and only one report in patient with ulcerative colitis on Ustekinumab.( 12 ) To our knowledge, this represents the first reported case of Bell’s palsy in a patient with Crohn’s disease receiving ustekinumab, following exclusion of alternative etiologies. The close temporal relationship, absence of alternative etiologies, and clinical resolution following drug withdrawal support a possible association with Ustekinumab. Although the precise mechanism remains unclear, inhibition of IL-12/23 signalling may alter Th1/Th17 immune balance and antiviral surveillance, potentially predisposing susceptible individuals to immune-mediated or post-infectious neuropathies. Similar immune perturbations have been invoked to explain demyelinating complications observed with other biologic agents, particularly anti-TNF therapies.( 13 ) In a similar way, long standing therapy with ustekinumab in this case may have impaired antiviral immune responses or altered immune regulation at the peripheral nerve level, potentially predisposing to acute neuropathy. Using the WHO–UMC causality assessment framework, this adverse event can be classified as “possible”, given the reasonable temporal relationship, exclusion of alternative explanations, and lack of rechallenge data. A rechallenge wasn’t done considering ethical reasons. Conclusion This case highlights Bell’s palsy as a rare but clinically relevant neurological adverse event temporally associated with ustekinumab therapy. While causality cannot be definitively established, the intention of reporting this case is to contribute to the post-marketing safety data and clinical awareness. Continued reporting of such cases is critical to better define the neurological safety profile of ustekinumab. Declarations Conflicts of Interest: The authors declare no conflicts of interest. Ethical Approval and Consent: Written informed consent was obtained from the patient for publication of this case report and accompanying images. Funding: None. Author Contribution KT - Review of Literature and inital draft.PBN - Review of literature, Table and final editing. References Lu J, Yin Z, Qiu Y, Yang Y, Chen Z, Wu J, et al. Exploring the Role of Inflammation and Metabolites in Bell’s Palsy and Potential Treatment Strategies. Biomedicines. 2025;13(4):957. Gogulescu A, Blidisel A, Soica C, Mioc A, Voicu A, Jojic A, et al. Neurological Side Effects of TNF-α Inhibitors Revisited: A Review of Case Reports. Med Kaunas Lith. 2024;60(9):1409. Yaqubi K, Kostev K, Klein I, Schüssler S, May P, Luedde T, et al. Inflammatory bowel disease is associated with an increase in the incidence of multiple sclerosis: a retrospective cohort study of 24,934 patients. Eur J Med Res. 2024;29(1):186. Gupta G, Gelfand JM, Lewis JD. Increased risk for demyelinating diseases in patients with inflammatory bowel disease. Gastroenterology. 2005 Sept;129(3):819–26. D’Amico F, Peyrin-Biroulet L, Danese S. Ustekinumab in Crohn’s Disease: New Data for Positioning in Treatment Algorithm. J Crohns Colitis. 2022;16(Suppl 2):ii30–41. Guo C, Zhao S. Adverse events associated with ustekinumab in Crohn’s disease treatment: an analysis based on the FAERS database. Front Med. 2025;12:1657247. Ghosh S, Feagan BG, Ott E, Gasink C, Godwin B, Marano C, et al. Safety of Ustekinumab in Inflammatory Bowel Disease: Pooled Safety Analysis Through 5 Years in Crohn’s Disease and 4 Years in Ulcerative Colitis. J Crohns Colitis. 2024;18(7):1091–101. Mishra A, Seril DN. Posterior Reversible Encephalopathy Syndrome following Ustekinumab Induction for Crohn’s Disease. Case Rep Gastroenterol. 2018;12(2):521–7. Jordan A, Kinnucan J. Ustekinumab-Associated Posterior Reversible Encephalopathy Syndrome in a Patient With Crohn’s Disease. ACG Case Rep J. 2022;9(10):e00867. Badat Y, Meissner WG, Laharie D. Demyelination in a patient receiving ustekinumab for refractory Crohn’s disease. J Crohns Colitis. 2014 Sept;8(9):1138–9. Honap S, Irving PM, Samaan MA. Ustekinumab-Induced Inflammatory Demyelinating Polyneuropathy in a Patient with Ulcerative Colitis. J Crohns Colitis. 2023;17(1):144–5. Petrou A, Wilgucki G, Wadhavkar N, Fine S. S3875 A Rare Case of Bell’s Palsy in a Patient With Ulcerative Colitis on Stelara. Off J Am Coll Gastroenterol ACG. 2024;119(10S):S2529. Kunchok A, Aksamit AJ Jr, Davis JM III, Kantarci OH, Keegan BM, Pittock SJ, et al. Association Between Tumor Necrosis Factor Inhibitor Exposure and Inflammatory Central Nervous System Events. JAMA Neurol. 2020;77(8):937–46. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Under Revision Version 1 posted Editorial decision: Revision requested 10 Dec, 2025 Editor assigned by journal 10 Dec, 2025 Submission checks completed at journal 10 Dec, 2025 First submitted to journal 08 Dec, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. 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1","display":"","copyAsset":false,"role":"figure","size":379039,"visible":true,"origin":"","legend":"\u003cp\u003eRight sided LMN type of facial palsy\u003c/p\u003e","description":"","filename":"Figure.jpg","url":"https://assets-eu.researchsquare.com/files/rs-8307283/v1/14e2516d28756e5526b5c426.jpg"},{"id":98445259,"identity":"1bca5286-7115-4b68-b709-95f10847f8ac","added_by":"auto","created_at":"2025-12-17 17:19:21","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":693955,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8307283/v1/a2ad330e-d2c8-42a9-9e25-97e01c5b207e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Isolated Bell's Palsy Associated with Ustekinumab in Crohn's Disease: Clinical Case and Review of Neurological Safety","fulltext":[{"header":"Introduction","content":"\u003cp\u003eBell\u0026rsquo;s palsy, an acute lower motor neuron facial nerve palsy, most commonly idiopathic, although associations with viral reactivation, immune dysregulation, and immunosuppressive states have been described. (\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e) In inflammatory bowel disease (IBD), biologic therapies have occasionally been implicated in neurological adverse events, particularly anti-TNF agents. (\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e) Ustekinumab, an interleukin-12/23 inhibitor, has a favourable safety profile, with neurological complications reported infrequently. We report a case of Bell\u0026rsquo;s palsy temporally associated with ustekinumab therapy in a patient with Crohn\u0026rsquo;s Disease (CD).\u003c/p\u003e"},{"header":"Case report","content":"\u003cp\u003eA 58-year-old man with a 34-month history of CD involving the colon with perianal fistulas, complicated by an anorectal stricture, now presented with an acute right-sided facial droop. \u003cb\u003e(\u003c/b\u003eFig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e\u003cb\u003e)\u003c/b\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003eThe patient was initially treated with infliximab in combination with azathioprine, achieving an initial clinical response. After the eighth dose of infliximab, he developed secondary loss of response, and was positive for anti-infliximab antibodies. Given persistent active perianal disease with discharge, he was initiated on ustekinumab. He had received a 520 mg intravenous induction dose, and was on 90 mg subcutaneous maintenance dosing every 8 weekly. The first five maintenance doses were well tolerated with improvement in disease activity in the form of reduced perianal discharge. A week after the sixth subcutaneous ustekinumab dose, the patient developed acute right-sided facial nerve palsy, characterized by inability to close the right eye and deviation of the mouth toward the left. On examination, vital signs were normal, and neurological examination revealed isolated right lower motor neuron facial nerve palsy.\u003c/p\u003e\u003cp\u003eMagnetic resonance imaging of the brain showed no structural or demyelinating lesions. Cerebrospinal fluid analysis was normal. Serological testing for herpes simplex virus and varicella-zoster virus was negative, as was antinuclear antibody testing. Otolaryngology evaluation excluded structural pathology involving the facial nerve within the fallopian canal.\u003c/p\u003e\u003cp\u003eIn view of the temporal relationship with ustekinumab exposure and exclusion of alternative aetiologies, a decision was made to withhold ustekinumab. The patient was initiated on short course of steroids and antiviral (acyclovir) by the neurology team. He was under close follow-up, showed a complete resolution at 12 weeks. The patient provided written informed consent for publication of this case report and any accompanying images.\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eIBD is known to be associated with an increased risk of several neurological disorders, particularly demyelinating diseases. Population based cohort studies have demonstrated an increased hazard of multiple sclerosis (MS) following a diagnosis of IBD in patients with UC and CD at 2.35 (95% CI: 1.47\u0026ndash;3.78) and 2.09 (95% CI: 1.28\u0026ndash;3.39) respectively. (\u003cspan class=\"CitationRef\"\u003e3\u003c/span\u003e) However, when demyelinating disorders (MS, Demyelination and Optic Neuritis) are analysed collectively, the overall risk in CD appears less consistent (IRR \u0026minus;\u0026thinsp;2.12, 95% CI: 0.94\u0026ndash;4.50) and is also not clearly associated with disease activity or concomitant immunosuppressive therapy.(\u003cspan class=\"CitationRef\"\u003e4\u003c/span\u003e)\u003c/p\u003e\n\u003cp\u003eUstekinumab, a monoclonal antibody targeting the p40 subunit of interleukin-12 (IL-12) and interleukin-23 (IL-23), is an established therapy for moderate-to-severe CD, including perianal phenotypes with an overall favourable safety profile. (\u003cspan class=\"CitationRef\"\u003e5\u003c/span\u003e) In contrast to other biologics like anti-TNF, no major neurological complications like demyelination was reported in the FAERS-based safety analysis of ustekinumab in CD. (\u003cspan class=\"CitationRef\"\u003e6\u003c/span\u003e) Another pooled analyses of ustekinumab trials in IBD which included 2575 patients and 4826 patient-years of follow-up reported no severe neurological complications or demyelinating disorders. (\u003cspan class=\"CitationRef\"\u003e7\u003c/span\u003e)\u003c/p\u003e\n\u003cp\u003eTo date, only isolated case reports of severe neurological adverse events associated with ustekinumab have been published, including posterior reversible encephalopathy syndrome (PRES), central and peripheral demyelinating disorders, and a single report of Bell\u0026rsquo;s palsy in ulcerative colitis.(\u003cspan class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e) The key published cases in IBD are summarized in Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\n\u003cdiv\u003eTable 1 Severe Neurological events associated with Ustekinumab therapy in IBD\u003c/div\u003e\n\u003ctable id=\"Taba\" border=\"1\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAuthor / Year\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eType of IBD\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDrug History\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eUstekinumab Regimen\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eNeurological Event\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eTime to Onset\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eDiagnostic Findings\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eManagement\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eOutcome\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eMishra \u0026amp; Seril, 2018 (\u003cspan class=\"CitationRef\"\u003e8\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCD - A1 B2/3P L3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMesalamine, 6-MP, methotrexate, infliximab\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e340 mg IV induction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePRES with seizures\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12 days post-induction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMRI: bilateral frontal, parietal, occipital T2/FLAIR hyperintensities\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStopped Ustekinumab. Antiepileptics\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFull recovery, MRI resolution\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCD - A3 B2P L3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMesalamine, ciprofloxacin, prednisone, thalidomide, infliximab, adalimumab\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e390 mg IV induction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAcute encephalopathy, atypical PRES\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6 days post-induction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMRI/MRA: scattered periventricular \u0026amp; subcortical T2/FLAIR signals\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStopped Ustekinumab.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eRecovery with mild residual headache.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eJordan \u0026amp; Kinnucan, 2022 (\u003cspan class=\"CitationRef\"\u003e9\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCD - A3 B3P L3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAdalimumab for 25 yrs\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e90 mg SC every 8 weeks maintenance for 2.5 yrs\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePRES with headache, weakness, urinary incontinence\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 months after last dose in maintenance phase\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMRI: multifocal T2/FLAIR hyperintensities in cerebellum, posterior fossa\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStopped Ustekinumab.\u003c/p\u003e\n \u003cp\u003eSwitched to vedolizumab.\u003c/p\u003e\n \u003cp\u003eAntihypertensives.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePartial recovery. Persistent hypertension \u0026amp; gait difficulty\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBadat et al. 2014 (\u003cspan class=\"CitationRef\"\u003e10\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCD - A2 B2 L1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAzathioprine, methotrexate, infliximab, adalimumab, certolizumab\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e90 mg SC every 12 weekly\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eCentral demyelination, Primary progressive MS\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAt 1 year after exposure\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eMRI: multiple periventricular \u0026amp; juxtacortical lesions; spinal cord lesion.\u003c/p\u003e\n \u003cp\u003eCSF: normal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eContinued ustekinumab.\u003c/p\u003e\n \u003cp\u003eMycophenolate.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePersistent neurological deficits.\u003c/p\u003e\n \u003cp\u003eCD in sustained clinical response.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eHonap et al. 2023 (\u003cspan class=\"CitationRef\"\u003e11\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eUC - E2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAdalimumab (prior demyelination), vedolizumab\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eIV induction followed by SC maintenance\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSub-acute inflammatory demyelinating polyneuropathy (SIDP)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5 days post-induction\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEMG/NCS: peripheral demyelination.\u003c/p\u003e\n \u003cp\u003eCSF: protein elevated.\u003c/p\u003e\n \u003cp\u003eMRI: normal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eStopped Ustekinumab.\u003c/p\u003e\n \u003cp\u003eIV Immunoglobulins given.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSignificant recovery.\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePetrou A 2024 (\u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eUC\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003esulfasalazine and mesalamine\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eUstekinumab therapy (induction phase)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBell\u0026rsquo;s palsy (CN VII palsy)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2 week after 1st dose\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eClinical exam: LMN facial nerve palsy.\u003c/p\u003e\n \u003cp\u003eBrain Imaging: Normal\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eContinued Ustekinumab.\u003c/p\u003e\n \u003cp\u003eShort course of steroid and antivirals.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFull recovery\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003ctd colspan=\"1\"\u003eCD \u0026ndash; Crohn\u0026rsquo;s disease, CSF \u0026ndash; Cerebrospinal fluid, EMG \u0026ndash; Electromyography, IV \u0026ndash; Intravenous, MRI \u0026ndash; Magnetic Resonance Imaging, NCS \u0026ndash; Nerve conduction studies, SC -Subcutaneous, UC \u0026ndash; ulcerative colitis.\u003c/td\u003e\n\u003cp\u003eBell\u0026rsquo;s palsy, although common in the general population, has been only rarely described in association with biologic therapy, and only one report in patient with ulcerative colitis on Ustekinumab.(\u003cspan class=\"CitationRef\"\u003e12\u003c/span\u003e) To our knowledge, this represents the first reported case of Bell\u0026rsquo;s palsy in a patient with Crohn\u0026rsquo;s disease receiving ustekinumab, following exclusion of alternative etiologies. The close temporal relationship, absence of alternative etiologies, and clinical resolution following drug withdrawal support a possible association with Ustekinumab.\u003c/p\u003e\n\u003cp\u003eAlthough the precise mechanism remains unclear, inhibition of IL-12/23 signalling may alter Th1/Th17 immune balance and antiviral surveillance, potentially predisposing susceptible individuals to immune-mediated or post-infectious neuropathies. Similar immune perturbations have been invoked to explain demyelinating complications observed with other biologic agents, particularly anti-TNF therapies.(\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e) In a similar way, long standing therapy with ustekinumab in this case may have impaired antiviral immune responses or altered immune regulation at the peripheral nerve level, potentially predisposing to acute neuropathy.\u003c/p\u003e\n\u003cp\u003eUsing the WHO\u0026ndash;UMC causality assessment framework, this adverse event can be classified as \u0026ldquo;possible\u0026rdquo;, given the reasonable temporal relationship, exclusion of alternative explanations, and lack of rechallenge data. A rechallenge wasn\u0026rsquo;t done considering ethical reasons.\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eThis case highlights Bell\u0026rsquo;s palsy as a rare but clinically relevant neurological adverse event temporally associated with ustekinumab therapy. While causality cannot be definitively established, the intention of reporting this case is to contribute to the post-marketing safety data and clinical awareness. Continued reporting of such cases is critical to better define the neurological safety profile of ustekinumab.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003ch2\u003eConflicts of Interest:\u003c/h2\u003e\u003cp\u003eThe authors declare no conflicts of interest.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eEthical Approval and Consent:\u003c/strong\u003e\u003cp\u003e Written informed consent was obtained from the patient for publication of this case report and accompanying images.\u003c/p\u003e\u003ch2\u003eFunding:\u003c/h2\u003e\u003cp\u003eNone.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eKT - Review of Literature and inital draft.PBN - Review of literature, Table and final editing.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eLu J, Yin Z, Qiu Y, Yang Y, Chen Z, Wu J, et al. Exploring the Role of Inflammation and Metabolites in Bell\u0026rsquo;s Palsy and Potential Treatment Strategies. Biomedicines. 2025;13(4):957.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGogulescu A, Blidisel A, Soica C, Mioc A, Voicu A, Jojic A, et al. Neurological Side Effects of TNF-α Inhibitors Revisited: A Review of Case Reports. Med Kaunas Lith. 2024;60(9):1409.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eYaqubi K, Kostev K, Klein I, Sch\u0026uuml;ssler S, May P, Luedde T, et al. Inflammatory bowel disease is associated with an increase in the incidence of multiple sclerosis: a retrospective cohort study of 24,934 patients. Eur J Med Res. 2024;29(1):186.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGupta G, Gelfand JM, Lewis JD. Increased risk for demyelinating diseases in patients with inflammatory bowel disease. Gastroenterology. 2005 Sept;129(3):819\u0026ndash;26.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eD\u0026rsquo;Amico F, Peyrin-Biroulet L, Danese S. Ustekinumab in Crohn\u0026rsquo;s Disease: New Data for Positioning in Treatment Algorithm. J Crohns Colitis. 2022;16(Suppl 2):ii30\u0026ndash;41.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGuo C, Zhao S. Adverse events associated with ustekinumab in Crohn\u0026rsquo;s disease treatment: an analysis based on the FAERS database. Front Med. 2025;12:1657247.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eGhosh S, Feagan BG, Ott E, Gasink C, Godwin B, Marano C, et al. Safety of Ustekinumab in Inflammatory Bowel Disease: Pooled Safety Analysis Through 5 Years in Crohn\u0026rsquo;s Disease and 4 Years in Ulcerative Colitis. J Crohns Colitis. 2024;18(7):1091\u0026ndash;101.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMishra A, Seril DN. Posterior Reversible Encephalopathy Syndrome following Ustekinumab Induction for Crohn\u0026rsquo;s Disease. Case Rep Gastroenterol. 2018;12(2):521\u0026ndash;7.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eJordan A, Kinnucan J. Ustekinumab-Associated Posterior Reversible Encephalopathy Syndrome in a Patient With Crohn\u0026rsquo;s Disease. ACG Case Rep J. 2022;9(10):e00867.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eBadat Y, Meissner WG, Laharie D. Demyelination in a patient receiving ustekinumab for refractory Crohn\u0026rsquo;s disease. J Crohns Colitis. 2014 Sept;8(9):1138\u0026ndash;9.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eHonap S, Irving PM, Samaan MA. Ustekinumab-Induced Inflammatory Demyelinating Polyneuropathy in a Patient with Ulcerative Colitis. J Crohns Colitis. 2023;17(1):144\u0026ndash;5.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003ePetrou A, Wilgucki G, Wadhavkar N, Fine S. S3875 A Rare Case of Bell\u0026rsquo;s Palsy in a Patient With Ulcerative Colitis on Stelara. Off J Am Coll Gastroenterol ACG. 2024;119(10S):S2529.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eKunchok A, Aksamit AJ Jr, Davis JM III, Kantarci OH, Keegan BM, Pittock SJ, et al. Association Between Tumor Necrosis Factor Inhibitor Exposure and Inflammatory Central Nervous System Events. JAMA Neurol. 2020;77(8):937\u0026ndash;46.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":true,"hideJournal":false,"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":"digestive-diseases-and-sciences","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ddsj","sideBox":"Learn more about [Digestive Diseases and Sciences](http://link.springer.com/journal/10620)","snPcode":"10620","submissionUrl":"https://submission.nature.com/new-submission/10620/3","title":"Digestive Diseases and Sciences","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Crohn’s disease, Ustekinumab, Bell’s palsy, Neurological adverse events, Biologic therapy","lastPublishedDoi":"10.21203/rs.3.rs-8307283/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8307283/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eUstekinumab is widely used in Crohn\u0026rsquo;s disease with a favourable safety profile, and neurological adverse events are rarely reported. We report a 58-year-old man with perianal fistulising Crohn\u0026rsquo;s disease who developed acute isolated lower motor neuron facial nerve palsy one week after sixth maintenance dose of ustekinumab. Extensive evaluation excluded infectious, autoimmune, structural, and otolaryngological causes. Ustekinumab was withheld, and the patient was treated conservatively with steroids and antivirals, with complete recovery over 12 weeks. This case highlights Bell\u0026rsquo;s palsy as a rare neurological adverse event temporally associated with ustekinumab and underscores the need for vigilance and continued post-marketing surveillance.\u003c/p\u003e","manuscriptTitle":"Isolated Bell's Palsy Associated with Ustekinumab in Crohn's Disease: Clinical Case and Review of Neurological Safety","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-12-15 21:18:40","doi":"10.21203/rs.3.rs-8307283/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-12-11T04:21:36+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-12-10T23:46:45+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-12-10T06:29:27+00:00","index":"","fulltext":""},{"type":"submitted","content":"Digestive Diseases and Sciences","date":"2025-12-08T11:28:14+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"digestive-diseases-and-sciences","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"ddsj","sideBox":"Learn more about [Digestive Diseases and Sciences](http://link.springer.com/journal/10620)","snPcode":"10620","submissionUrl":"https://submission.nature.com/new-submission/10620/3","title":"Digestive Diseases and Sciences","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"b4539a87-d6df-4493-aa32-fd5853282be4","owner":[],"postedDate":"December 15th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"in-revision","subjectAreas":[],"tags":[],"updatedAt":"2025-12-15T21:18:41+00:00","versionOfRecord":[],"versionCreatedAt":"2025-12-15 21:18:40","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8307283","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8307283","identity":"rs-8307283","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}