Cerebellitis as a Rare Manifestation of HSV Encephalitis: A Case Report
DOI:
https://doi.org/10.5195/ijms.2025.3131Keywords:
Herpes Simplex Encephalitis, Herpes Encephalitis, Herpetic Encephalitis, Herpes Simplex Virus 1, Cerebellar AtaxiaAbstract
Background: Herpes Simplex Virus (HSV) is a common cause of encephalitis. A feared complication of HSV encephalitis is hemorrhage and necrosis of the brain parenchyma most commonly in the temporal lobe(s). Less common sites of focal necrosis include the insula and inferior frontal lobes. A rare presentation of HSV encephalitis is cerebellitis.
Case: A 74-year-old female presented with a 1-month history of progressive balance difficulty and dizziness. The neurological exam showed truncal ataxia and scanning dysarthria. Serum labs were largely unremarkable, except for elevated sedimentation rate (ESR). Brain MRI revealed diffuse cerebellar swelling and T2 signal changes, with left medial enhancement. Cerebrospinal fluid (CSF) analysis showed elevated red blood cells (WBCs 5, RBCs 438, protein 54.7, glucose 64) and was positive for HSV-1 PCR. The CSF autoimmune encephalopathy panel was negative. She was treated with acyclovir 10 mg/kg every 8 hours for 14 days and IV methylprednisolone 1000 mg daily for 5 days, followed by an oral prednisone taper. Clinical improvement in ataxia and dizziness was observed soon after treatment began, with decreased cerebellar edema and enhancement on repeat MRI. After discharge, the patient was lost to follow-up, and long-term neurological status remains unknown.
Conclusions: Recognition of atypical HSV encephalitis is crucial as encephalitis has a broad differential and CSF HSV PCR is a widely available and highly specific test. Rapid administration of acyclovir is the current standard of care. Addition of pulse dose methylprednisolone may also impart symptomatic and radiographic benefit.
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References
Armangué T, Olivé-Cirera G, Martínez-Hernández E, Rodés M, Peris-Sempere V, Guasp M, et al. Neurologic complications in herpes simplex encephalitis: clinical, immunological and genetic studies. Brain. 2023;146(10):4306–19.
Bradshaw MJ, Venkatesan A. Herpes simplex virus-1 encephalitis in adults: pathophysiology, diagnosis, and management. Neurotherapeutics. 2016;13(3):493–508.
Campos LG, Rossato R, Santos RP, Duarte JA, Vedolin L. Acute cerebellitis caused by herpes simplex virus. Clin Biomed Res. 2019;39(1):104–5.
Ciardi M, Giacchetti G, Fedele CG, Tenorio A, Brandi A, Libertone R, et al. Acute cerebellitis caused by herpes simplex virus type 1. Clin Infect Dis. 2003;36(3):e50–4.
Guerreiro Stucklin AS, Grotzer MA. Cerebellar tumors. Cerebellum Disord Treat. 2018;155:289–99.
Hodzic E, Hasbun R, Granillo A, Tröscher AR, Wagner H, Tim M, et al. Steroids for the treatment of viral encephalitis: a systematic literature review and meta-analysis. J Neurol. 2023;270:3603–15.
Jouan Y, Grammatico-Guillon L, Espitalier F, Cazals X, François P, Guillon A. Long-term outcome of severe herpes simplex encephalitis: a population-based observational study. Crit Care. 2015;19(1):1–9.
Kamei S. Evaluation of combination therapy using aciclovir and corticosteroid in adult patients with herpes simplex virus encephalitis. J Neurol Neurosurg Psychiatry. 2005;76(11):1544–9.
McKeon A. Purkinje cell cytoplasmic autoantibody type 1 accompaniments. Arch Neurol. 2011;68(10):1282.
Meyding-Lamadé U, Jacobi C, Martinez-Torres F, Lenhard T, Kress B, Kieser M, et al. The German trial on aciclovir and corticosteroids in herpes-simplex-virus-encephalitis (GACHE): a multicenter, randomized, double-blind, placebo-controlled trial. Neurol Res Pract. 2019;1(1):1–10.
Paketci C, Edem P, Okumus C, Sarioglu FC, Bayram E, Hiz S, et al. Herpes simplex virus-1 as a rare etiology of isolated acute cerebellitis: case report and literature review. J Neurovirol. 2019;26(2):270–2.
Pedroso JL, Vale TC, Braga-Neto P, Dutra LA, França MC Jr, Teive HAG, et al. Acute cerebellar ataxia: differential diagnosis and clinical approach. Arq Neuropsiquiatr. 2019;77(3):184–93.
Ramos-Estebanez C, Lizarraga KJ, Merenda A. A systematic review on the role of adjunctive corticosteroids in herpes simplex virus encephalitis: is timing critical for safety and efficacy? Antivir Ther. 2013;19(2):133–9.
Sawaishi Y, Takada G. Acute cerebellitis. Cerebellum. 2002;1(3):223–8.
Matthews E, Beckham JD, Piquet AL, Tyler KL, Chauhan L, Pastula DM. Herpesvirus-associated encephalitis: an update. Curr Trop Med Rep. 2022;9(3):92–100

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