Beyond Parkinson's: The Challenge of Diagnosing Multiple System Atrophy-C

Multiple system atrophy (MSA) is a rare, rapidly progressive neurodegenerative disorder characterized by varying combinations of Parkinsonian features, cerebellar ataxia, and autonomic dysfunction. The disease is classified into two major subtypes based on predominant symptoms: The Parkinsonian variant (MSA-P) and the cerebellar variant (MSA-C). MSA-C, in particular, presents significant diagnostic challenges due to its overlapping clinical features with other neurodegenerative disorders, such as cerebellar ataxias and atypical Parkinsonian syndromes. Early stages of the disease may not show conclusive findings on conventional imaging, further complicating diagnosis. We report a case of a middle-aged woman who presented with progressive ataxia, dysarthria, orthostatic symptoms, and urinary disturbances. Initial clinical assessment and structural imaging were inconclusive. The patient showed poor response to standard pharmacological therapy, including levodopa. This prompted further evaluation with functional imaging, which demonstrated regional hypometabolism in the brainstem and cerebellum - findings supportive of a diagnosis of MSA-C. Comprehensive autoimmune and metabolic workups were negative, reinforcing the clinical suspicion. This case highlights the importance of a thorough diagnostic approach in patients with progressive cerebellar and autonomic symptoms. While definitive biomarkers for MSA are lacking, advanced imaging techniques such as fluorodeoxyglucose positron emission tomography can provide supportive evidence in challenging cases. Early identification of MSA, even when classic signs like the "hot cross bun" sign are absent on magnetic resonance imaging, is essential to initiate symptomatic treatment, plan supportive care, and guide patient and family counseling.