Objective: To report a case of CV2-positive autoimmune encephalitis presenting as dystonia–parkinsonism, underscoring the need to consider autoimmune etiologies in atypical dystonic syndromes.

Background: Autoimmune encephalitis may present with seizures, psychiatric or cognitive symptoms, and a broad range of movement disorders. Dystonia–parkinsonism has been reported in antibody‑mediated encephalitis but is exceptionally described with CV2/CRMP5 antibodies.

Method: We describe a man evaluated at the Department of Neurology, Mongi Ben Hamida National Institute of Neurology, for seizures and abnormal movements. Clinical examination, brain MRI, EEG, CSF analysis, blood tests, onconeural antibody screening, and thoraco‑abdomino‑pelvic CT scan were performed.

Results: This 61‑year‑old patient had a 4‑year history of generalized seizures, followed by depressive symptoms and cognitive decline. Examination revealed memory impairment, right hemiparesis and hemisensory loss, static cerebellar syndrome, and ophthalmoplegia. The most prominent feature was a painful right‑hand dystonia with contralateral akinetic‑rigid parkinsonism. Brain MRI showed bilateral subcortical and periventricular T2/FLAIR hyperintensities, and CSF was normal. Serum testing detected anti‑CV2 antibodies, whereas infectious, systemic autoimmune, and oncological work‑up remained negative, consistent with CV2‑positive non‑paraneoplastic autoimmune encephalitis. High‑dose intravenous methylprednisolone induced only slight and transient improvement, followed by relapse and death.

Conclusion: Dystonia–parkinsonism can be the leading manifestation of CV2‑positive autoimmune encephalitis. Early recognition of this phenotype should prompt urgent onconeural antibody testing and timely initiation of treatment.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/dystonia-parkinsonism-revealing-cv2-positive-autoimmune-encephalitis/