New-Onset Progressive Ataxia in a 66-Year-Old Woman with Longstanding Parkinson’s Disease: A Case Report

The occurrence of new symptoms in PD, especially "red flags" or exclusion criteria, calls for a repeated diagnostic work-up to exclude potentially treatable causes of parkinsonism. While SS has been reported as a cause of symptomatic parkinsonism, we favor a diagnosis of idiopathic PD and comorbid SS in this case. This case report highlights the clinical importance of diagnostic criteria in differentiating PD from atypical parkinsonian disorders or symptomatic parkinsonism as well as signs and symptoms, pathophysiological aspects, and treatment of SS.