A case of autoimmune encephalitis characterized by cerebellar ataxia with anti CV2 antibody

We report a case of autoimmune encephalitis with cerebellar ataxia as the main manifestation. The main clinical manifestation of the patient was persistent vertigo with headache. Plain and enhanced MRI of the head suggested multiple lesions in bilateral cerebellar hemispheres and right temporo-occipital lobe. Examinations of the nervous system: Romberg test, finger-to-nose test, and heel-knee-shin test were positive; paraneoplastic syndrome-related antibody test in blood and cerebrospinal fluid showed that anti CV2 antibody was positive. Diagnosis: Autoimmune encephalitis with anti CV2 antibody. The symptoms improved after regular intravenous infusion of cyclophosphamide combined with hormone treatment. Anti CV2 antibody can cause subacute cerebellar degeneration. Therefore, when cerebellar ataxia is the main clinical manifestation of patients and imaging indicates cerebellar lesions, it is necessary to consider the possibility of autoimmune encephalitis with anti CV2 antibody.