Amyotrophic Lateral Sclerosis

Definition

Definition of Amyotrophic Lateral Sclerosis
Amyotrophic lateral sclerosis (ALS), also referred to as Lou Gehrig's disease in American English and motor neurone disease in British English, is a form of motor neurone disease caused by the degeneration of upper and lower neurons, located in the ventral horn of the spinal cord and the cortical neurons that provide their efferent input.

Symptoms

Symptoms of Amyotrophic Lateral Sclerosis
The disorder causes muscle weakness and atrophy throughout the body caused by degeneration of the upper and lower motor neurons. Unable to function, the muscles weaken and atrophy. Affected individuals may ultimately lose the ability to initiate and control all voluntary movement, although bladder and bowel sphincters and the muscles responsible for eye movement are usually, but not always, spared.

Cognitive function is generally spared for most patients although some (~5%) also have frontotemporal dementia. A higher proportion of patients (~30-50%) also have more subtle cognitive changes which may go unnoticed but are revealed by detailed neuropsychological testing. Sensory nerves and the autonomic nervous system, which controls functions like sweating, are generally unaffected but may be involved for some patients.

Causes

Causes of Amyotrophic Lateral Sclerosis
Researchers are studying several possible causes of ALS, including:

1. Gene mutation: Various genetic mutations can lead to inherited forms of ALS, which appear nearly identical to the non-inherited forms.
2. Chemical imbalance: People who have ALS typically have higher than normal levels of glutamate, a chemical messenger in the brain, around the nerve cells in their spinal fluid. Too much glutamate is known to be toxic to some nerve cells.
3. Disorganized immune response: Sometimes a person's immune system begins attacking some of his or her body's own normal cells, and scientists have speculated that this may trigger the process that results in ALS.
4. Protein mishandling: There's evidence that mishandled proteins within the nerve cells can lead to a gradual accumulation of abnormal forms of these proteins in the cells, eventually causing the nerve cells to die.

Diagnosis

Diagnosis of Amyotrophic Lateral Sclerosis
No test can provide a definite diagnosis of ALS, although the presence of upper and lower motor neuron signs in a single limb is strongly suggestive. Instead, the diagnosis of ALS is primarily based on the symptoms and signs the physician observes in the patient and a series of tests to rule out other diseases. Physicians obtain the patient's full medical history and usually conduct a neurologic examination at regular intervals to assess whether symptoms such as muscle weakness, atrophy of muscles, hyperreflexia, and spasticity are getting progressively worse.

Treatment

Treatment of Amyotrophic Lateral Sclerosis
Because there's no reversing the course of amyotrophic lateral sclerosis, treatments mainly involve efforts to slow the progression of symptoms and make you more comfortable and independent.

Medications: The drug riluzole (Rilutek) is the first and only medication approved by the Food and Drug Administration for slowing ALS. The drug appears to slow the disease's progression in some people, perhaps by reducing levels of glutamate - a chemical messenger in the brain that's often present in higher levels in people with ALS.

Your doctor may also prescribe medications to provide relief from:

1. Muscle cramps
2. Constipation
3. Fatigue
4. Excessive salivation
5. Excessive phlegm
6. Pain
7. Depression

1. Physical therapy: A physical therapist can recommend low-impact exercises to maintain your cardiovascular fitness, muscle strength and range of motion as long as possible, helping you preserve a sense of independence. Regular exercise can also help improve your sense of well-being.
2. Occupational therapy: An occupational therapist can help you become accustomed to a brace, walker or wheelchair and may be able to suggest devices such as ramps that make it easier for you to get around.
3. Speech therapy: Because ALS affects the muscles you use to speak, communication becomes an issue as the disease progresses. A speech therapist can help teach adaptive techniques to make your speech more clearly understood or help you explore alternative methods of communication, such as an alphabet board or simple pen and paper. Later in the disease, a speech therapist can recommend devices such as speech synthesizers and computer-based equipment that may help you communicate. Ask your therapist about the possibility of borrowing or renting these devices.

Prognosis

Prognosis of Amyotrophic Lateral Sclerosis
Eventually most people with ALS are not able to stand or walk, get in or out of bed on their own, use their hands and arms, or communicate. In later stages of the disease, individuals have difficulty breathing as the muscles of the respiratory system weaken. Although respiratory support can ease problems with breathing and prolong survival, it does not affect the progression of ALS. Most people with ALS die from respiratory failure, usually within three to five years from the onset of symptoms. The median survival time from onset to death ranges from 20 to 48 months, but 10 to 20% of ALS patients have a survival longer than 10 years. The world's most widely recognized person with ALS, Stephen Hawking, has lived with the disease for more than 40 years, though his is an unusual case.

Prevention

Prevention of Amyotrophic Lateral Sclerosis
You may want to see a genetic counselor if you have a family history of ALS.