Recurrent severe and long-lasting cerebellar ataxia attacks in adult-onset neuronal intranuclear inclusion disease

Neuronal intranuclear inclusion disease (NIID) is a progressive neurodegenerative disease that is characterized by eosinophilic hyaline intranuclear inclusions. NIID presents highly variable clinical manifestations such as dementia, ataxia, convulsion, neuropathy, and autonomic dysfunction. A 60-year-old woman developed recurrent severe cerebellar ataxia (SARA score: 30/40 points). She was diagnosed with adult-onset NIID by a characteristic brain diffusion-weighed imaging hyperintensity lesion in subcortical white matter and intranuclear inclusion bodies in a skin biopsy. Her ataxia was more severe and lasted longer (additional 19 days) than a previous case, although she showed remarkable improvement.