Question:
What is ALS?
Answer: ALS is a progressive disease of the motor neurons.
Question:
What are the motor neurons?
Answer: The motor neurons are the nerve cells that are located in
the brain, brain stem and the spinal cord, and represent the central station
of the motor nerves that supplies the voluntary muscles throughout the body.
Question:
What are the symptoms and signs of ALS?
Answer: ALS patients usually present with a progressive weakness
of different groups of voluntary muscles. The most commonly effected
muscles are those of the tongue and swallowing, leading to the slurring of
speech and difficulty in swallowing. The upper and lower extremity
muscles are also affected, leading to wasting and twitching of these
muscles. The involvement of the upper motor neurons that are located in
the cerebral cortex causes an increase in the reflexes and tone of the
effected muscles. This mixture of the involvement of the upper and lower
motor neurons is the hallmark of the diagnosis of ALS.
Question:
What functions are usually not affected by ALS?
Answer: Involuntary muscles, such as those that move the
bowel and stomach, are usually not affected. The muscles that move the
eyes are not affected. Urinary incontinence and bowel incontinence is
very uncommon due to the lack of involvement of the involuntary muscles of the
bladder and bowel. Sexual function is preserved. Sensation is not
affected. Vision, hearing and mental status remains intact usually
throughout the course of the disease.
Question:
What is the target age group of ALS?
Answer: ALS affects all age groups and both sexes, but the
disease usually strikes adults between 35 and 65 years old.
Question:
How is ALS diagnosed?
Answer: Clinical evaluation is essential. The
involvement of the upper and lower motor neurons is the diagnostic hallmark of
the disease. Upper motor neuron involvement is expressed as increased
reflexes. Lower motor neurons involvement presents as a weakness and
wasting of the bulbar and the limb muscles. The presence of increased
reflexes in wasted muscles is very typical.
EMG is the most important diagnostic test. It involves inserting
electrodes into the involved muscles and measuring the electrical activity.
Muscle biopsy, in which a piece of muscle is removed under local anesthesia,
may help to establish the diagnosis, although the findings are not
pathognomonic.
Question:
What does a muscle biopsy show in ALS?
Answer: ALS is not diagnosed by muscle biopsy. Muscle
biopsy may be needed to look for evidence of loss of nerve supply (denervation)
to muscles that are not clinically involved. Denervation, in a
clinically strong muscle proves the notion of widespread denervation, which is
the diagnostic hallmark of the disease. Denervation in the muscle biopsy
is identified by NADH reaction. Denervated fibers look like small and
angular, and stain excessively with NADH. In less progressive forms of
ALS, reinnervation is also demonstrated in ATP-ase reaction. Muscle
biopsy also helps to exclude certain myopathies, which can mimic ALS, such as
inclusion body myositis and acid maltase deficiency.
Question:
What is the prognosis of ALS?
Answer: ALS progresses within 3-5 years. Usually, death
results from paralysis of the respiratory muscles or aspiration
pneumonia. The disease is more progressive if it starts in the bulbar
muscles, leading to difficulty in swallowing and speech, followed by
difficulty in breathing. Some cases progress very slowly over decades.
Question:
Is ALS hereditary?
Answer: About 10% of ALS patients have a family history of
the disorder. Recently, a mutation in the SOD1 gene on chromosome 21 has
been identified as a cause of this type of ALS.
Question:
Is ALS treatable?
Answer: So far, no cure has been found for ALS.
Riluzole, a glutamate antagonist, is the first medication ever approved for
treatment of ALS. It seems to modestly extend survival time. Other
medications are being tested, such as Gabapentin. Neurotrophic growth
factors are also being tried.
Question:
Why is ALS also referred to as Lou Gehrig's disease?
Answer: ALS first came to the wide public attention when the
Hall of Fame career of Yankee's first baseman, Lou Gehrig, was cut short by
the disease in 1939. Gehrig died in 1941. Many people still use
the term, Lou Gehrig's disease, when referring to ALS.