From probable Parkinson’s disease to clinically established MSA-P: A 10-year longitudinal case report with delayed dysautonomia

Early differentiation of multiple system atrophy-parkinsonian subtype (MSA-P) from Parkinson’s disease (PD) remains challenging, particularly when autonomic dysfunction is absent during the early disease course. We report a 72-year-old woman who initially presented with asymmetric parkinsonism and was considered to have probable PD. Within the first five years, however, several red flags for an atypical parkinsonian syndrome became evident, including persistently poor levodopa responsiveness, relatively rapid motor progression, bilateral striatal hypometabolism on fluorodeoxyglucose positron emission tomography, and progressive posterior putaminal atrophy with iron deposition on serial magnetic resonance imaging. Definite orthostatic hypotension emerged approximately six years after motor onset, prompting revision of the diagnosis from PD to MSA-P. During the subsequent 18 months, dysphagia, severe dysarthria, recurrent falls, urinary retention, urinary incontinence, and a postvoid residual volume of 262 mL developed, together supporting clinically established MSA-P under the 2022 Movement Disorder Society criteria. At ten-year follow-up, the patient was semi-bedridden with marked postural deformity and complete loss of independent mobility. This case illustrates a delayed-dysautonomia phenotype in which diagnostic autonomic manifestations lagged behind motor and neuroimaging abnormalities by several years. It emphasizes the importance of early recognition of atypical red flags, repeated diagnostic reassessment, and longitudinal multimodal imaging when an apparent PD phenotype evolves atypically.