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MSA

Multiple system atrophy is a progressive brain disorder that affects movement and balance and disrupts the function of the autonomic nervous system. 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.

[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.

[Forms of MSA]

Two forms of MSA, are recognized, according to whether Parkinsonian or cerebellar symptoms predominate1. 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

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 treatment for MSA. Treatment is aimed at controlling the symptoms of the disease. Drugs to treat people with Parkinson’s disease, most notably levodopa (given in tablets of Sinemet), 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, in most cases, the effectiveness of this therapy decreases over time. 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 (Symmetrel).

[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.

3. "Multiple-System Atrophy". 2015. New England Journal Of Medicine 372 (3): 249-263. doi:10.1056/nejmra1311488.

4. Reference, Genetics. 2018. "Multiple System Atrophy". Genetics Home Reference. https://ghr.nlm.nih.gov/condition/multiple-system-atrophy.

5. "Symptoms, Causes & Types Of Multiple System Atrophy". 2018. MSA. https://www.multiplesystematrophy.org/about-msa/types-symptoms.