title: Expanding concept of clinical conditions and symptoms in multiple system atrophy.
abstract: Multiple system atrophy (MSA) is an adult-onset, progressive neurodegenerative disorder. MSA patients show various phenotypes during the course of their illness including parkinsonism, cerebellar ataxia, autonomic failure, and pyramidal signs. MSA is classified into the parkinsonian (MSA-P) or cerebellar (MSA-C) variant depending on the clinical motor phenotype at presentation. MSA-P and MSA-C are predominant in Western countries and Japan, respectively. The mean age at onset is 55 to 60 years. Prognosis ranges from 6 to 10 years, but some cases survive for more than 15 years. Early and severe autonomic failure is a poor prognostic factor. MSA patients sometimes present with isolated autonomic failure or motor symptoms/signs, and the median duration from onset to the concomitant appearance of motor and autonomic symptoms was approximately 2 years in our previous study. As the presence of the combination of motor and autonomic symptoms is essential for the current diagnostic criteria, early diagnosis is difficult when patients present with isolated autonomic failure or motor symptoms/signs. We experienced MSA patients who died before presentation of the motor symptoms/signs diagnostic for MSA (i.e., premotor MSA). Detection of the nature of autonomic failure consistent with MSA and identification of the dysfunctional anatomical sites may increase the probability of a diagnosis of premotor MSA. Dementia is another problem in MSA. Although dementia had been thought to be rare in MSA, frontal lobe dysfunction is observed frequently during the early course of the illness. Magnetic resonance imaging can show progressive cerebral atrophy in longstanding cases. More recently, MSA patients presenting with frontotemporal dementia preceding the presence of motor and autonomic manifestations diagnostic of MSA have been reported. Novel diagnostic criteria based on an expanding concept of the clinical conditions and symptoms of MSA will be needed for the development of disease-modifying therapies and better management.
authors.affiliation: Brain and Mind Research Center, Nagoya University.
authors.forename: Hirohisa
authors.initials: H
authors.lastname: Watanabe
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Riku
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Nakamura
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Hara
authors.forename: Mizuki
authors.initials: M
authors.lastname: Ito
authors.forename: Masaaki
authors.initials: M
authors.lastname: Hirayama
authors.forename: Mari
authors.initials: M
authors.lastname: Yoshida
authors.forename: Masahisa
authors.initials: M
authors.lastname: Katsuno
authors.forename: Gen
authors.initials: G
authors.lastname: Sobue
mesh_terms: D001259:Ataxia / Q000209:etiology; D001284:Atrophy; D001342:Autonomic Nervous System Diseases / Q000209:etiology; D003645:Death, Sudden; D018450:Disease Progression; D042241:Early Diagnosis; D005625:Frontal Lobe / Q000473:pathology; D057180:Frontotemporal Dementia / Q000209:etiology; D006801:Humans; D019578:Multiple System Atrophy / Q000145:classification / Q000175:diagnosis / Q000473:pathology / Q000503:physiopathology