Multiple System Atrophy

Progressive neurodegenerative disorder

Multiple system atrophy (MSA) is a disorder in which multiple parts of the nervous system experience degeneration. The term encompasses three syndromes (Shy-Drager syndrome, striatonigral degeneration, and olivopontocerebellar atrophy) which were once thought to be unrelated but are now understood to all be parts of the same disorder. What causes the loss of nerve cells in multiple system atrophy is not known.

Multiple system atrophy is estimated to occur in 2-15 individuals per 100,000. Many individuals with multiple system atrophy do not receive the correct diagnosis because it can be difficult to distinguish MSA from other disorders. Multiple system atrophy is usually diagnosed after age 40 (average age is early 50s), occurs in people of all ethnic backgrounds. Individuals usually experience a fast progression of the disorder.

Symptoms
The symptoms experienced in multiple system atrophy come from the loss of nerve cells in the nervous system. Symptoms are grouped into three main categories:

• Autonomic dysfunction – symptoms such as urinary incontinence, erectile dysfunction in men, drop in blood pressure when standing (orthostatic hypotension), fainting, constipation
• Parkinsonism – tremors at rest, rigidity of muscles, slowness in moving
• Cerebellar dysfunction – difficulty walking (ataxia), maintaining balance, and coordinating voluntary movements.

Other symptoms such as difficulty speaking or swallowing, sleep apnea, and cold hands may be present.

Diagnosis
Many individuals with multiple system atrophy first notice urinary incontinence (females) or erectile dysfunction (males). Upon examination, orthostatic hypotension may be discovered, as well as symptoms of Parkinsonism such as tremors. In fact, it can be very difficult to distinguish multiple system atrophy from Parkinson’s disease. One clue is that individuals with MSA do not respond well to the medication (levodopa) that is used to treat Parkinson’s.

Currently, the only way a definitive diagnosis of MSA can be made is during autopsy after death. Specialized testing by a neurologist can rule out other types of rare neurological disorders, such as progressive supranuclear palsy.

Treatment
No current treatment is available that can reverse or stop the progression of multiple system atrophy. Some aspects of the disorder are debilitating and difficult to treat. Management of orthostatic hypotension is important, because the dizziness it causes limits physical activity. There are a number of medications available to treat this problem.

The disorders with movement can be treated with levodopa/carbodopa (Sinemet), but this usually has limited results. Other medications that may be used are bromocriptine (Parlodel), trihexyphenidyl (Artane), benztropine mesylate (Cogentin), and amantadine (Symmetrel). Physical therapy, including aqua therapy, can help maintain muscle function, and speech therapy can help with difficulty in swallowing or speaking.

Research
Little is known about the mechanisms at work in multiple system atrophy. Researchers at the University of Pennsylvania’s Center for Neurodegenerative Disease Research have developed a strain of mice with symptoms similar to MSA in humans. They plan to test these mice with potential treatments for MSA and work to gain a better understanding of the disorder.

Information for this article was taken from:
- Diedrich, A., & Robertson, D. (2002). Multiple system atrophy. eMedicine, accessed at http://www.emedicine.com/neuro/topic671.htm
- University of Pennsylvania Medical Center. First mouse model for multiple system atrophy points to new treatment targets for brain diseases. Press release dated 4/1/05.