Multiple system atrophy - The putative causative role of environmental toxins

Background: Whereas a number of studies have investigated the putative role of environmental toxins in the pathogenesis of idiopathic Parkinson diseas e, the possibility of such a role in multiple system atrophy has received l ittle attention. Design and Setting: Review of records of patients examined in the Parkinson 's Disease Center and Movement Disorder Clinic, Baylor College of Medicine, Houston, Tex, from July 1, 1977, to February 4, 1998. Patients: We reviewed 100 consecutive medical records of patients who satis fied the diagnostic criteria for multiple system atrophy formulated by the Consensus Committee of the American Autonomic Society and the American Acad emy of Neurology. Intervention: The type and amount of toxin exposure were verified by histor y and examination of records whenever er possible. Severity of parkinsonism was assessed by clinical rating scales. Main Outcome Measure: Development of multiple system atrophy after environm ental toxin exposure. Results: Eleven patients had a notable history of heavy exposure to environ mental toxins. One patient with multiple system atrophy confirmed by postmo rtem evaluation was exposed to high concentrations of malathion, diazinon, and formaldehyde, while the other patients with multiple system atrophy had well-documented high exposures to agents including n-hexsane, benzene, met hyl isobutyl ketone, and pesticides. The case studied pathologically demons trated extensive advanced glial changes, including glial cytoplasmic inclus ions in deep cerebellar white matter, brainstem, cortex (superior frontal, insula) and putamen, with notable cell loss and depigmentation of the subst antia nigra and locus ceruleus. Conclusion: While many studies report a possible role of environmental toxi ns in Parkinson disease, such a role is even more likely in multiple system atrophy, as this is a sporadic disease.