ALS

ALS: Description

ALS stands for Amyotrophic Lateral Sclerosis.

ALSAmyotrophic lateral sclerosis (ALS), often referred to as "Lou Gehrig's Disease," is a progressive neurodegenerative disease that affects nerve cells in the brain and the spinal cord. Motor neurons reach from the brain to the spinal cord and from the spinal cord to the muscles throughout the body. The progressive degeneration of the motor neurons in ALS eventually leads to their death. When the motor neurons die, the ability of the brain to initiate and control muscle movement is lost. With voluntary muscle action progressively affected, patients in the later stages of the disease may become totally paralyzed.

A-myo-trophic comes from the Greek language. "A" means no or negative. "Myo" refers to muscle, and "Trophic" means nourishment-"No muscle nourishment." When a muscle has no nourishment, it "atrophies" or wastes away. "Lateral" identifies the areas in a person's spinal cord where portions of the nerve cells that signal and control the muscles are located. As this area degenerates it leads to scarring or hardening ("sclerosis") in the region.

As motor neurons degenerate, they can no longer send impulses to the muscle fibers that normally result in muscle movement. Early symptoms of ALS often include increasing muscle weakness, especially involving the arms and legs, speech, swallowing or breathing. When muscles no longer receive the messages from the motor neurons that they require to function, the muscles begin to atrophy (become smaller). Limbs begin to look "thinner" as muscle tissue atrophies.

ALS destroys motor neurons that are an important link in the nervous system, and through which the brain controls the voluntary muscles throughout the body.

Leg and foot muscles are controlled by motor neurons in the lower spinal cord. Arm, hand and finger muscles are controlled by motor neurons in the upper spinal cord. Speaking, swallowing and chewing are controlled by motor neurons in the brain stem.

ALS does not affect the five senses of sight, hearing, taste, smell and touch, nor does it normally affect the mind, eye muscles, heart, bladder, bowel, or sexual muscles. There is no possibility that ALS is contagious.

Type of ALS: The most common form of this is called Sporadic ALS. In addition, about 5% of patients have an inherited variety called Familial ALS. Until recently, an abnormally high incidence of ALS was observed in the Western Pacific. As a result of extensive research into Guamanian ALS, it is now thought that these high incidence rates were due to specific dietary toxins (for example, Aluminium, cycasin). With the Westernization of this region, and the reduced dependency on traditional food stuffs, dramatic declines in the incidence of ALS in this region have occurred.

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. It 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 this 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.

Symptoms

The early symptoms of ALS may seem rather vague. They can include tripping, dropping things, slurred or "thick" speech, and muscle cramping, weakening, and twitching. Some people with these early symptoms may tend to assume that they are normal signs of aging. As the disease progresses, the muscles of the trunk of the body are affected. Weakness of the breathing muscles develops slowly over months or years.

For some people, the muscles for speaking, swallowing or breathing are the first to be affected. This is known as Bulbar ALS. The term “bulbar” refers to the motor neurons located in the bulb region of the brain stem, that control the muscles used for chewing, swallowing, and speaking. ALS symptoms, and the order in which they occur, vary from one person to another.

The rate of muscle loss can vary significantly from person to person, with some patients having long periods with very slow degeneration. Although the average life expectancy of newly diagnosed people is between 3 and 5 years, 20% live more than 5 years, and 10% live more than 10 years. Being a progressive disease, it may spread throughout the body over time, and at some point in this process, may involve the muscles required for breathing.

Causes and Risk factors

The cause of ALS is not known, and scientists do not yet know why ALS strikes some people and not others. An important step toward answering that question came in 1993 when scientists supported by the National Institute of Neurological Disorders and Stroke (NINDS) discovered that mutations in the gene that produces the SOD1 enzyme were associated with some cases of familial ALS. This enzyme is a powerful antioxidant that protects the body from damage caused by free radicals. Free radicals are highly reactive molecules produced by cells during normal metabolism. If not neutralized, free radicals can accumulate and cause random damage to the DNA and proteins within cells. Although it is not yet clear how the SOD1 gene mutation leads to motor neuron degeneration, researchers have theorized that an accumulation of free radicals may result from the faulty functioning of this gene. In support of this, animal studies have shown that motor neuron degeneration and deficits in motor function accompany the presence of the SOD1 mutation.

Studies also have focused on the role of glutamate in motor neuron degeneration. Glutamate is one of the chemical messengers or neurotransmitters in the brain. Scientists have found that, compared to healthy people, ALS patients have higher levels of glutamate in the serum and spinal fluid. Laboratory studies have demonstrated that neurons begin to die off when they are exposed over long periods to excessive amounts of glutamate. Now, scientists are trying to understand what mechanisms lead to a buildup of unneeded glutamate in the spinal fluid and how this imbalance could contribute to the development of ALS.

Autoimmune responses—which occur when the body's immune system attacks normal cells—have been suggested as one possible cause for motor neuron degeneration in ALS. Some scientists theorize that antibodies may directly or indirectly impair the function of motor neurons, interfering with the transmission of signals between the brain and muscles.

In searching for the cause of ALS, researchers have also studied environmental factors such as exposure to toxic or infectious agents. Other research has examined the possible role of dietary deficiency or trauma. However, as of yet, there is insufficient evidence to implicate these factors as causes of ALS.

Future research may show that many factors, including a genetic predisposition, are involved in the development of ALS.

Diagnosis

ALS can be difficult to diagnose in the early stages, when symptoms may mimic other conditions. However, there are clinical signs that can be indicative of a wasting of motor neurons in either the upper or lower portion of the spine.

As such, clinicians familiar with ALS usually see the following signs of lower and upper motor neuron degeneration:

Lower Motor Neuron Degeneration:

1. Muscle weakness and atrophy.

2. Involuntary contraction of muscle fibers.

3. Muscle cramps.

4. Weakened reflexes.

5. Flaccidity (decreased muscle tone).

6. Difficulty swallowing.

7. Disordered articulation.

8. Shortness of breath at rest.

Upper Motor Neuron Degeneration:

1. Muscle stiffness or rigidity.

2. Emotional lability (decreased ability to control emotions).

3. Some may assume that these are signs of normal aging. Over time, as muscles continue to weaken, and the weakening spreads throughout the body, it becomes more apparent that the cause is ALS.

In addition to a physical examination, people are often given an EMG, blood tests, a MRI (Magnetic Resonance Imaging), and other tests to search for the presence of other diseases that can look like ALS.

Doctors who do not usually see people with ALS may be reluctant to suggest it as a possible diagnosis. They normally refer the person to a neurologist. Telling someone and his or her family that the person may have it requires a sensitive, understanding and compassionate manner. People should also be told about the disease, current research and drug trials, as well as about support services and the ALS Society in their province.

Treatment

There is no cure for ALS. Treatment focuses on relieving symptoms and maintaining an optimal quality of life. Treatment is based on individual therapy and the continual adaptation of medications. Riluzole (Rilutek®) is one of the few drugs so far proven to be effective against ALS and may prevent progression and prolong life for a few months or so. Riluzole decreases the release of glutamate.

Side effects include the following:

1. Dizziness.

2. Elevated liver enzymes.

3. Reduced leukocytes in the blood (granulocytopenia).

4. Weakness (asthenia).

Baclofen (Lioresol®) or tizanadine (Zanaflex®) may relieve spasticity. Side effects include increased weakness, sedation, and dizziness. Nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen may relieve general discomfort. Due to potentially severe gastrointestinal and cardiovascular side effects, NSAIDs should only be used as instructed. Tramadol (Ultram®) is often prescribed for pain relief.

Physical therapy is an important part of treatment and helps to relieve cramping and muscular pain. Passive stretching helps to avoid permanent contraction of muscles (contractures) that may cause joint problems.

Other therapies, such as occupational therapy and speech therapy, are also used in treatment. ALS patients require a diet of high-energy foods that are easy to swallow. Patients may benefit from a nutritionist. If the patient is not able to maintain adequate nutrition, a percutaneous endoscopic gastrostomy (PEG), or feeding tube, is usually inserted. This has been shown to prolong life in ALS patients who are losing weight.

Some ALS patients may also need pulmonary consultants and respiratory therapists to assist breathing. Fewer than 5% of patients use long-term ventilation support. Noninvasive forms of breathing assistance (e.g., continuous positive airway pressure [CPAP], bilevel positive airway pressure [BiPAP]) may be used to improve the patient's quality of life).

Depression is very common among ALS patients. Antidepressant medication and counseling can help patients and their families cope.

Medicine and medications

List of drugs and medications that are commonly prescribed to treat ALS: Ceftriaxone, Minocycline, Rilutek, and Riluzole.

DISCLAIMER: This information should not substitute for seeking responsible, professional medical care.

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