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MSA

Multiple system atrophy (MSA) is a progressive neurodegenerative movement disorder characterized by autonomic failure like tremors, slow movement . The autonomic nervous system controls body functions that are mostly involuntary, such as regulation of blood pressure. The most frequent autonomic symptoms associated with multiple system atrophy are a sudden drop in blood pressure upon standing (orthostatic hypotension), urinary difficulties, and erectile dysfunction in men. The cause of MSA is not certain and the risk factors are still unknown.

[Epidemiology]

The prevalence of MSA is reported to be between 3.4-4.9 cases per 100,000 populations. The estimated mean incidence is 0.6-0.7 cases per 100,000 person-years. MSA meets orphan disease status.

MSA has been encountered in Caucasian, African, and Asian populations. In Western countries, MSA-P predominates, occurring in 66-82% of patients. In Eastern countries (e.g., Japan), MSA-C is common, occurring in 67% of patients.

The disease more often affects men than women. The female-to-male ratio is around 1:2. (A ratio of 1:3-9 has also been reported.) However, the early and easy diagnosis of impotence may have led to the male statistical predominance of MSA. The mean age at onset in MSA is 52.5-55 years. The disease progresses over intervals of 1-18 years.

[Types of MSA]

According to whether Parkinsonian or cerebellar symptoms predominate, MSA can be divided into two types. Both types involve autonomic dysfunction, or dysautonomia. Autonomic symptoms usually appear first, though either motor symptoms or autonomic symptoms may appear first in the Parkinsonian type.

1. the parkinsonian type (MSA-P), with primary characteristics similar to Parkinson’s disease (such as moving slowly, stiffness, and tremor) along with problems of balance, coordination, and autonomic nervous system dysfunction. In the early stage, medications used for Parkinson’s Disease are effective to this form of MSA. However, MSA tends to progress more quickly than Parkinson’s disease. Consequently, patients no longer respond to Parkinson’s disease medication.

2. the cerebellar type (MSA-C), with primary symptoms featuring ataxia (problems with balance and coordination), difficulty swallowing, speech abnormalities or a quavering voice, and abnormal eye movements (“cerebellar” reflects a part of the brain involved with coordination)

[Treatment & Unmet medical needs]

There is no specific treatments to delay the progressive neurodegeneration of MSA. Treatment is aimed at helping people cope with some of the more disabling symptoms of MSA. Levodopa that are used to treat people with Parkinson’s disease may also be prescribed for individuals with MSA. However, the effectiveness of such medications varies greatly among affected individuals. In many cases, individuals do not respond or respond poorly to such therapy. Approximately 1/3 of affected individuals respond to levodopa therapy. However, the effectiveness of this therapy may not continue as the disease progresses in most cases. In addition, these drugs must be used with caution because they may lower blood pressure.

In addition to levodopa, other drugs used to treat Parkinson’s disease may be used to treat individuals with MSA. These include dopamine agonists such as ropinirole (Requip) and pramipexole (Mirapexin) and an antiviral drug known as amantadine.

[Reference]

1. "Multiple System Atrophy Information Page | National Institute Of Neurological Disorders And Stroke". 2018. Ninds.Nih.Gov. https://www.ninds.nih.gov/Disorders/All-Disorders/Multiple-System-Atrophy-Information-Page.

2. "Multiple System Atrophy: Background, Etiology And Pathophysiology, Epidemiology". 2018. Emedicine.Medscape.Com. https://emedicine.medscape.com/article/1154583-overview.