A 68-year-old Caucasian female was admitted to the emergency department with a progressive history of behavioural symptoms and anxiety followed by visual and auditory hallucinations, forgetfulness, and impaired gait in the previous 3 months. On examination she was psychotic and had a postural and rest tremor of the upper limbs, cogwheel rigidity of the four limbs, retropulsion on standing position, and inability to walk. During the following 2 weeks she developed xerostomia and unilateral parotiditis that improved with steroids. A simultaneous improvement of the cognitive abilities allowed for the detection of sensory ataxia of the lower limbs. Sensory ganglionopathy was then detected with electrophysiological studies. A diagnosis of Sjögren syndrome was suspected and confirmed by salivary gland scintigraphy, Schirmer's test, and submaxillary gland biopsy. We report a case of Sjögren syndrome associated with central and peripheral nervous system involvement, without sicca symptoms preceding the neurological clinical picture. The coexistence of ganglionopathy and a favourable response to immunosuppression are key features that can lead to the correct diagnosis in cases with atypical CNS symptoms, mimicking a rapidly progressive dementia.