ALS is the abbreviation for "Amyotrophic Lateral Sclerosis." "A-myo-trophic" comes from the
Greek language. "A" means no or negative. "Myo" refers to muscle, and "Trophic" means
nutrition or stimulation. When a muscle has no stimulation, it "atrophies" or wastes away.
"Lateral" identifies the area of the spinal cord where the pathways for motor nerves, those that innervate
the muscles, are located. As this area degenerates it leads to scarring or hardening, "sclerosis," in the
region.
ALS is a progressive neuromuscular disease. It attacks motor neurons in the brain and spinal cord which transmit
signals to the voluntary muscles throughout the body. When motor neurons die as a result of ALS, the ability of the
brain to control muscle movement is lost. Weakness spreads to all the voluntary muscles and progresses to paralysis.
ALS does not affect sensory nerves so there is no loss of feeling in the paralyzed areas. ALS only affects motor
pathways in the brain so awareness, thought and intelligence are not usually affected even after paralysis makes
it impossible for the patient to communicate. Frontal Lobe Dementia causing behavioral and personality
changes is not uncommon with ALS, however.
In the United States, ALS is also known as Lou Gehrig's Disease after the baseball player who died from ALS.
In other countries it is often called "Motor Neuron Disease." This leads to some confusion because there
are several other forms of motor neuron diseases such as SMA (Spinal Muscular Atrophy) and Kennedy's Disease.
ALS is actually just one of the motor neuron diseases. Currently, ALS is categorized into two forms, Familial and
Sporadic. About 10% of ALS patients have Familial ALS which is an inherited disease. The majority have Sporadic ALS
in which no family history can be found. There is no difference in the symptoms and progression of the familial and
the sporadic forms of the illness.
Cause
Even though changes in the levels of a substance called glutamate have been identified as being at least a part
of the process that kills the motor neurons, the cause of the increased glutamate is not fully understood. Research
continues to look for links between ALS, genetics, toxins, antioxidants, viruses, and autoimmunity. Although some
scientists believe it is possible that ALS is caused by a slow-acting or latent virus, no such virus has ever been
identified, and there is no increased incidence among family members, caregivers or medical personnel who
are in close contact with ALS patients. Many researchers believe that in the end it will be found that there are
many ways in which the process of motor neuron degeneration can be triggered and therefore several possible causes
of ALS.
Who Gets ALS?
ALS occurs throughout the world with no racial, ethnic or socioeconomic boundaries. Most people who develop ALS
are between the ages of 40 and 70. It is not uncommon among people in their twenties and thirties, however. Men are
affected slightly more frequently than women.
ALS is not an extremely rare disease. The incidence is about 2 new cases per 100,000 every year. Because life
expectancy is so short, the number of ALS patients alive at any time is low, but about 5,000 people in the U.S. are
newly diagnosed with ALS each year.
Signs and Symptoms of ALS
Even before weakness is noted, muscle twitches, (fasciculations) are common. Other patients notice a stiffness
in their arms and legs. Many have increased muscle cramping. Some people first experience weakness in their arms or
legs. This is referred to as limb-onset ALS. Arm weakness is somewhat more common and begins with a weakening of the
grip and fumbling fingers. Leg weakness causes fatigue when walking, difficulty climbing stairs, stumbling. For
others, the first symptoms may involve problems with speaking or swallowing: Slurred speech, a nasal tone, or
choking easily. This is bulbar-onset ALS.
As the disease progresses, the weakness becomes more severe and spreads to other areas of the body. Although one
side of the body may be a little ahead of the other in deteriorating, ALS is usually quite symmetrical. Eventually,
arms and legs, swallowing and speech and breathing are all affected. As the muscles weaken, affected areas
atrophy, appearing
thin and wasted. Muscle cramping and twitching eases as the weakness turns into paralysis, but the twitching and
cramping moves on to newly affected muscles. In some patients, the stiffness noted earlier increases to severe
spasticity and hyperactive reflexes.
Although the areas of the body first affected and the rate of progression varies, the progression of the disease
is generally steady. Plateaus have been documented but are often more a matter of function than an actual delay in
the spreading of the weakness. For example, a patient may seem to plateau after beginning to use a wheelchair.
Because he is no longer attempting to walk, further weakness of his legs is less notable. Involuntary muscles are
not affected, so the heart, bladder, and bowel are not directly affected.
The senses, including vision, hearing, and touch, are not affected. Although intelligence and thought are not
generally affected, some ALS patients do experience a problem with their emotional responses sometimes referred to
as "pseudobulbar emotionality." They find themselves bursting into tears or into helpless laughter even
though they are not thinking or feeling overly sad or amused. The mechanism for this misdirected response is unclear
and can be very distressing and embarrassing for the patient. It is often assumed that weeping spells are due to
depression since depression is certainly common in ALS patients. However, if inappropriate laughter is also seen,
this emotional lability is probably not an indication of emotional problems but rather a physical "short
circuit" in the pathways between emotional thought and the motor responses.
A small percentage of ALS patients do experience a concurrent progressive dementia. The dementia is not
considered part of the usual ALS disease process but rather an added complication in which other areas of the brain
are atypically susceptible to the process that is destroying the motor neurons. In these patients, personality
changes, mood swings, irritability, unreasonableness occur. Early on it can be very difficult to differentiate
between a possible dementia and an inability to cope with the stresses of the disease. If dementia occurs, it is
usually obvious before the patient loses the ability to communicate so it should never be assumed that a late stage,
non-communicating patient has become demented or vegetative.
Diagnosis
At present there is no definitive means of diagnosis of ALS. Most diagnoses are made by eliminating all other
possibilities—ailments whose symptoms resemble those of ALS. Neurologists use a number of clinical tests to
establish a profile, including blood testing, EMG, MRI, etc.
Life Expectancy
Average life expectancy for ALS patients is 2-5 years with the cause of death being respiratory failure, most
often hastened by pneumonia. Weakening of the inspiratory and expiratory muscles compromises the ability to cough
and clear pulmonary secretions. Respiratory failure usually results from an upper-respiratory infection that
develops into pneumonia. When swallowing problems occur, aspiration greatly increases the incidence of repeated
pneumonia and respiratory failure can occur long before the patient actually reaches the point where his respiratory
muscles are too weak to sustain breathing.
Just as the onset and progression of extremity weakness and swallowing/speech problems varies, so does the onset
of ventilatory muscle weakness. It may occur early on before arms and/or legs are paralyzed, or later. It may
precede, coincide with, or follow the onset of swallowing and speech problems.
While the average life expectancy for ALS patients is 2-5, twenty percent of patients will live more than five
years. Up to 10% will survive more than ten years. A very small percentage progress very slowly and may survive as
long as 15 or 20 years or more.
It is important to note that these figures are based on patients who do not go on Bi-level Ventilator or a
full ventilator. Patients who opt for tube feedings and a ventilator when swallowing and respiratory muscles
fail can generally be maintained for many more years. Life expectancy among these patients has not been reported,
but the patient's age, other health problems and the quality of nursing care available will affect life
expectancy.
A decision to go on a ventilator does not halt the disease progress, however. Paralysis will continue to
progress and all movement including facial expression, eye movement, blinking may eventually be lost. The patient
can become "Locked In", meaning that a fully alert and aware mind is trapped in a body that won't
allow communication with caregivers.
