Purpose: Common etiologies of acute acquired cerebellar ataxia include cerebrovascular diseases, toxin or drugs, infections/para-infections, and autoimmune diseases. It is a rare manifestation of Sjögren's syndrome, which is a common autoimmune disease but is often missed as a differential diagnosis.
Case report: This is a report of a patient with acute onset cerebellar ataxia for one month. She also had massive neck lymphadenopathy. After a series of studies and the exclusion of other common causes of acute cerebellar ataxia, she was diagnosed as having Sjögren's syndrome. Patients with Sjögren's syndrome have higher risk for lymphoma, which leads to poorer prognosis. After lymph node biopsy, the patient was proven to have sinus histiocytosis, which is another rare finding in Sjögren's syndrome.
Discussion: For patients with acute acquired cerebellar ataxia, immune-mediated cerebellar ataxia should be an important differential diagnosis aside from the more common causes like stroke or drugs.