Multiple system atrophy is a progressive, fatal disorder that causes symptoms resembling those of Parkinson disease (parkinsonism), loss of coordination, and malfunction of internal body processes (such as blood pressure and bladder control).
The parts of the brain that control movements and many internal body processes degenerate.
Symptoms include symptoms that resemble those of Parkinson disease, loss of coordination, low blood pressure when a person stands (orthostatic hypotension), problems with urination, and constipation.
Simple measures and medications can help lessen symptoms, but the disorder is progressive and ultimately fatal.
(See also Overview of the Autonomic Nervous System.)
Multiple system atrophy usually begins when people are in their 50s. It affects men and women equally.
There are two types of multiple system atrophy (MSA), based on which symptoms occur first:
MSA-C is characterized by loss of coordination and difficulty maintaining balance, which indicates cerebellar dysfunction (indicated by the C).
Both types involve autonomic nervous system dysfunction. Although multiple system atrophy begins as one of these types, symptoms of the other type eventually develop. After about 5 years, symptoms tend to be similar regardless of which disorder developed first.
Causes of Multiple System Atrophy
Multiple system atrophy results from degeneration of several parts of the brain and spinal cord:
The basal ganglia (collections of nerve cells at the base of the cerebrum, deep within the brain), which help control voluntary muscle movements by balancing the actions of muscle groups that move the same muscles in opposite ways (for example, a group that bends an arm and a group that straightens the arm)
The cerebellum, which coordinates voluntary movements (particularly complex movements done simultaneously) and helps maintain balance
Areas that control the autonomic nervous system, which regulates involuntary body processes, such as how blood pressure changes in response to changes in posture
The cause of the degeneration is unknown, but degeneration in multiple system atrophy probably results when alpha-synuclein changes shape (misfolds) and accumulates in support cells in the brain. Alpha-synuclein is a protein in the brain that helps nerve cells communicate, but whose function is not yet fully understood. Abnormal alpha-synuclein can also accumulate in people with pure autonomic failure, Parkinson disease, or dementia with Lewy bodies.
Rapid eye movement (REM) sleep behavior disorder often occurs in people with disorders that involve accumulation of alpha-synuclein, including multiple system atrophy.
Locating the Cerebellum and Basal Ganglia
The cerebellum is located below the cerebrum just above the brain stem. The cerebellum coordinates the body’s movements. With information it receives from the cerebral cortex and the basal ganglia about the position of the limbs, the cerebellum helps the limbs move smoothly and accurately. (The cerebral cortex is the convoluted layer of tissue that forms the outer surface of the cerebrum. It contains most of the nerve cells in the nervous system.) The basal ganglia are collections of nerve cells located deep within the brain. They include the following structures:
The basal ganglia help smooth out muscle movements and coordinate changes in posture. |
Symptoms of Multiple System Atrophy
Multiple system atrophy is a progressive disorder. Early symptoms of multiple system atrophy vary, depending on which part and how much of the brain is affected first. The disorder causes three groups of symptoms.
Parkinsonism—symptoms that resemble those of Parkinson disease—may occur. These symptoms result from degeneration in the basal ganglia. Muscles are stiff (rigid), and movements become slow, shaky, and difficult to initiate. When walking, people may shuffle and not swing their arms. People feel unsteady and off balance, making them more likely to fall. Posture may be stooped. Limbs may tremble jerkily, usually when they are held in one position. But people with multiple system atrophy are less likely to have tremors during rest than people with Parkinson disease. Articulating words is difficult, and the voice may become high-pitched and quaver.
Loss of coordination may occur. It results from degeneration in the cerebellum. People lose their balance. Later, they may be unable to control movements of their arms and legs. Consequently, they have difficulty walking and take wide, irregular steps. When reaching for an item, they may reach beyond it. When sitting, they may feel unstable. People may have difficulty focusing their eyes on and following objects. Tasks that require rapidly alternating movements, such as turning a door knob or screwing in a light bulb, also become difficult.
Malfunction of internal body processes, controlled by the autonomic nervous system, may also occur. Blood pressure may decrease dramatically when a person stands up, causing dizziness, light-headedness, or fainting—a condition called orthostatic hypotension. Blood pressure may increase when a person lies down.
People may need to urinate urgently or frequently or may pass urine involuntarily (urinary incontinence). They may have difficulty emptying the bladder (urinary retention). Constipation is common. Vision becomes poor. Men may have difficulty initiating and maintaining an erection (erectile dysfunction).
Other symptoms of autonomic malfunction may include the following:
Less sweat, tears, and saliva are produced. As a result, people may become intolerant of heat and have dry eyes and mouth.
People may have difficulty swallowing and breathing.
Breathing may be noisy and high-pitched.
During sleep, breathing may stop repeatedly or become inadequate (sleep apnea).
If REM sleep behavior disorder develops, people speak and may wave their arms or legs violently during sleep, possibly because they are acting out vivid, frightening dreams.
People may lose control of bowel movements (fecal incontinence).
Many people are confined to a wheelchair or are otherwise severely disabled within 5 years after symptoms begin. The disorder results in death usually about 9 to 10 years after symptoms begin.
Diagnosis of Multiple System Atrophy
A doctor's evaluation
Magnetic resonance imaging
Tests to evaluate the autonomic nervous system
Magnetic resonance imaging (MRI) is usually done to check for certain changes in the brain.
Tests to evaluate the autonomic nervous system are done. They include the thermoregulatory sweat test and measurement of blood pressure while the person is sitting and after the person stands to check for orthostatic hypotension.
If MRI shows changes that suggest multiple system atrophy and test results are abnormal, multiple system atrophy is likely.
Treatment of Multiple System Atrophy
Symptom relief
No treatment can cure multiple system atrophy. However, a combination of simple measures and medications may help relieve symptoms.
Decreased production of body fluids: If sweating is reduced or absent, people should avoid warm environments to avoid overheating the body. Good dental care and regular check-ups are essential for people with dry mouth. Artificial tears (eye drops containing substances that resemble real tears) applied every few hours may relieve dry eyes.
Constipation: A high-fiber diet and stool softeners are recommended. If constipation persists, enemas may be necessary.
As the multiple system atrophy progresses, some people need a breathing tube, feeding tube (usually surgically inserted), or both.
Physical, occupational, and speech therapists can teach people ways to compensate when walking, doing daily activities, and speaking become difficult. Specialists in palliative medicine focus on relieving pain and treating symptoms and helps people deal with end-of-life issues. Social workers can help people find support groups and, when symptoms become disabling, home health care or hospice services.
End-of-life issues
Because the disorder is progressive and ultimately fatal, people should prepare advance directives soon after the disorder is diagnosed. These directives should indicate what kind of medical care people want at the end of life.
