Amyotrophic Lateral Sclerosis (cont.)
Who gets ALS?
As many as 20,000 Americans have ALS, and an estimated 5,000 people in the
United States are diagnosed with the disease each year. ALS is one of the most
common neuromuscular diseases worldwide, and people of all races and ethnic
backgrounds are affected. ALS most commonly strikes people between 40 and 60
years of age, but younger and older people also can develop the disease. Men are
affected more often than women.
In 90 to 95 percent of all ALS cases, the disease occurs
apparently at random
with no clearly associated risk factors. Patients do not have a family history
of the disease, and their family members are not considered to be at increased
risk for developing ALS.
About 5 to 10 percent of all ALS cases are inherited. The familial form of
ALS usually results from a pattern of inheritance that requires only one parent
to carry the gene responsible for the disease. About 20 percent of all familial
cases result from a specific genetic defect that leads to mutation of the enzyme
known as superoxide dismutase 1 (SOD1). Research on this mutation is providing
clues about the possible causes of motor neuron death in ALS. Not all familial
ALS cases are due to the SOD1 mutation, therefore other unidentified genetic
causes clearly exist.
What are the symptoms of ALS?
The onset of ALS may be so subtle that the symptoms are frequently
overlooked. The earliest symptoms may include:
- twitching, cramping,
or stiffness of muscles;
- muscle weakness affecting an arm or a leg;
- slurred and
nasal speech;
or
- difficulty chewing or swallowing.
These general complaints then develop into
more obvious weakness or atrophy that may cause a physician to suspect ALS.
The parts of the body affected by early symptoms of ALS depend on which
muscles in the body are damaged first. In some cases, symptoms initially affect
one of the legs, and patients experience awkwardness when walking or running or
they notice that they are tripping or stumbling more often. Some patients first
see the effects of the disease on a hand or arm as they experience difficulty
with simple tasks requiring manual dexterity such as buttoning a shirt, writing,
or turning a key in a lock. Other patients notice speech problems.
Regardless of the part of the body first affected by the
disease, muscle weakness and atrophy spread to other parts of the body as the
disease progresses. Patients have increasing problems with moving, swallowing
(dysphagia), and speaking or forming words (dysarthria). Symptoms of upper motor
neuron involvement include tight and stiff muscles (spasticity) and
exaggerated reflexes (hyperreflexia) including an overactive gag reflex. An
abnormal reflex
commonly called Babinski's sign (the large toe extends upward as the sole of the
foot is stimulated in a certain way) also indicates upper motor neuron damage.
Symptoms of lower motor neuron degeneration include muscle weakness and atrophy,
muscle cramps, and fleeting twitches of muscles that can be seen under the skin
(fasciculations).
To be diagnosed with ALS, patients must have signs and symptoms of both upper
and lower motor neuron damage that cannot be attributed to other causes.
Although the sequence of emerging symptoms and the rate of disease
progression vary from person to person, eventually patients will not be able to
stand or walk, get in or out of bed on their own, or use their hands and arms.
Difficulty swallowing and chewing impair the patient's ability to eat normally
and increase the risk of choking. Maintaining
weight will then become a problem. Because the disease usually does not affect
cognitive abilities, patients are aware of their progressive loss of function
and may become anxious and depressed. A small percentage of patients may
experience problems with memory or decision-making, and there is growing
evidence that some may even develop a form of dementia.
Health care
professionals need to explain the course of the disease and describe available
treatment options so that patients can make informed decisions in advance. In
later stages of the disease, patients have difficulty breathing as the muscles of the respiratory system
weaken. Patients eventually lose the ability to breathe on their own and must
depend on ventilatory support for survival. Patients also face an increased risk
of pneumonia during later
stages of ALS.
Next: How is ALS diagnosed? »
- riluzole oral tablets, Rilutek - Consumer information about the medication RILUZOLE ORAL TABLETS (Rilutek), includes side effects, drug interactions, recommended dosages, and storage information. Read more about the prescription drug RILUZOLE ORAL TABLETS.
- Electromyogram (EMG) - EMG (electromyogram) can detect abnormal muscle electrical activity in conditions such as neuropathy, carpal tunnel syndrome, pinched nerves, herniated discs, peripheral nerve damage, ALS, and more.
- Muscle Spasms - Read about muscle spasms, their causes, diagnosis, treatment and prevention. Symptoms and signs include acute pain at the site of the muscle contractions (twitches or fasciculations).
Latest Medical News
Neurology RSS