Autonomic failure and reduced survival in multiple system atrophy

Non-pharmacological and drug treatment of autonomic dysfunction in multiple system atrophy: current status and future directions

Multiple system atrophy (MSA) is a sporadic, fatal, and rapidly progressive neurodegenerative disease of unknown etiology that is clinically characterized by autonomic failure, parkinsonism, cerebellar ataxia, and pyramidal signs in any combination. Early onset and extensive autonomic dysfunction, including cardiovascular dysfunction characterized by orthostatic hypotension (OH) and supine hypertension, urinary dysfunction characterized by overactive bladder and incomplete bladder emptying, sexual dysfunction characterized by sexual desire deficiency and erectile dysfunction, and gastrointestinal dysfunction characterized by delayed gastric emptying and constipation, are the main features of MSA. Autonomic dysfunction greatly reduces quality of life and increases mortality. Therefore, early diagnosis and intervention are urgently needed to benefit MSA patients. In this review, we aim to discuss the systematic treatment of autonomic dysfunction in MSA, and focus on the current methods, starting from non-pharmacological methods, such as patient education, psychotherapy, diet change, surgery, and neuromodulation, to various drug treatments targeting autonomic nerve and its projection fibers. In addition, we also draw attention to the interactions among various treatments, and introduce novel methods proposed in recent years, such as gene therapy, stem cell therapy, and neural prosthesis implantation. Furthermore, we elaborate on the specific targets and mechanisms of action of various drugs. We would like to call for large-scale research to determine the efficacy of these methods in the future. Finally, we point out that studies on the pathogenesis of MSA and pathophysiological mechanisms of various autonomic dysfunction would also contribute to the development of new promising treatments and concepts.

Interrelationships between Survival, Sex, and Blood Pressure in Patients with Multiple System Atrophy

OBJECTIVE

The aim of this study is to estimate survival among patients with multiple system atrophy-parkinsonian type (MSA-P) or cerebellar type MSA (MSA-C) in relation to blood pressure (BP) measurements, by sex.

METHODS

A cohort of 99 MSA patients was studied retrospectively. Their BP measurements were obtained during prolonged (40 min, vertical position) drug-free tilt testing. We used K-M survival curves and Cox regression to calculate adjusted (to age of onset) hazard ratios (HRs) of BP measurements on time to death by MSA subtype and sex.

RESULTS

Fifty-two MSA patients were males and 47 were females. Sixty-three of them had MSA-P and 36 had MSA-C. The mean age at motor symptom onset was 61.1 ± 10.4 years, and mean disease duration at the time of BP assessment was 8.0 ± 4.7 years. The 2 study groups (MSA-P and MSA-C) did not differ significantly in age at MSA onset, sex ratio, or disease duration. Survival time did not differ between the groups {medians: 12 years (95% confidence interval [CI]: 8-28) and 10 years (95% CI: 8-13), respectively}. The MSA-P group showed a trend towards better survival for males (log-rank p = 0.0925). The maximal diastolic orthostatic BP decline during tilt testing had a borderline positive association with death risk among MSA-C males (adjusted HR = 1.18, p = 0.0665), and systolic BP after 10 min in a supine position had a significant positive association with death risk among MSA-P males (adjusted HR = 1.06, p = 0.0354).

CONCLUSIONS

The findings of a sex-based difference in the effect of BP on death risk may be important for adjusting the therapeutic approach to MSA patients.

The Shaking Palsy of the Larynx-Potential Biomarker for Multiple System Atrophy: A Pilot Study and Literature Review

In its early stages multiple system atrophy (MSA), a neurodegenerative movement disorder, can be difficult to differentiate from idiopathic Parkinson's disease (PD), and emphasis has been put on identifying premotor symptoms to allow for its early identification. The occurrence of vegetative symptoms in addition to motor impairment, such as orthostatic hypotension and neurogenic bladder dysfunction, enable the clinical diagnosis in the advanced stages of the disease. Usually with further disease progression, laryngeal abnormalities become clinically evident and can manifest in laryngeal stridor due to impaired vocal fold motion, such as vocal fold abduction restriction, mostly referred to as vocal fold paresis, or paradoxical vocal fold adduction during inspiration. While the pathogenesis of laryngeal stridor is discussed controversially, its occurrence is clearly associated with reduced life expectancy. Before the clinical manifestation of laryngeal dysfunction however, abnormal vocal fold motion can already be seen in patients that might not yet fulfill the diagnostic criteria of MSA. In this article we summarize the current literature on pharyngolaryngeal findings in MSA and report preliminary findings from a pilot study investigating eight consecutive MSA patients. Patients showed varying speech abnormalities. Only 2/8 patients exhibited laryngeal stridor. However, during FEES, all patients presented with irregular arytenoid cartilages movements and vocal fold abduction restriction. 3/8 showed vocal fold fixation and 1/8 paradoxical vocal fold motion. All patients presented with oropharyngeal dysphagia, 5/8 with penetration or aspiration events. We suggest that specific abnormal vocal fold motion can help identifying MSA patients and may allow for delimiting this disorder from idiopathic PD. These findings therefore may serve as a novel clinical biomarker for MSA. Based on the available data and our preliminary clinical experience we developed a standardized easy-to-implement task-protocol to be performed during flexible endoscopic evaluation of swallowing (FEES) for detection of MSA-related pharyngolaryngeal movement disorders. Furthermore, we initiated a prospective study to evaluate the diagnostic utility of this protocol.