Amyotrophic lateral sclerosis

It is a degenerative disease that primarily affects the neurons that control voluntary muscle movement. It quickly leads to a limiting state caused by the weakness of the muscles needed to move, speak, eat, or breathe. It is a rare disorder with a global incidence of between 0.6 to 3.8 cases per 100,000 inhabitants per year.

The cause of ALS is unknown; however, scientific evidence suggests that both genetics and the environment play a role in the degeneration of motor neurons and the development of ALS. In addition to the hereditary factor that accounts for 5-10% of cases, some of the established risk factors for amyotrophic lateral sclerosis include the following:

• Age: The risk of amyotrophic lateral sclerosis increases with age and is most common between the ages of 40 and mid-60s.
• Gender: Before the age of 65, amyotrophic lateral sclerosis is slightly more common in men than in women. This gender difference disappears after the age of 70.
• Smoking: Smoking is the only likely environmental risk factor for amyotrophic lateral sclerosis. The risk appears to be higher for women, particularly after menopause.
• Exposure to environmental toxins: Some evidence suggests that exposure to lead or other substances could be related to amyotrophic lateral sclerosis, although no agent or chemical substance has been consistently associated with it.
• Exposure to infectious agents or viruses, physical trauma, diet, strenuous physical activity, and behavioral and occupational factors could impact the development of this disease.

The symptoms of amyotrophic lateral sclerosis vary greatly from person to person. The onset usually begins with muscle weakness that can be so subtle that the symptoms go unnoticed. Over time, it worsens, and the symptoms become more evident as weakness or atrophy that prevents the performance of routine activities. The most common symptoms include:

• Muscle spasms and cramps, especially in the hands and feet.
• Loss of motor control in the hands and arms, muscle stiffness (spasticity), and deterioration in the use of arms and legs.
• Weakness and fatigue.
• Tripping and falling.
• Uncontrollable periods of laughter or crying.
• Difficulty speaking or projecting the voice.

As the disease progresses, symptoms may include shortness of breath, difficulty breathing and swallowing, and paralysis. ALS patients eventually lose the ability to breathe on their own and must rely on a respirator. Affected individuals also face a higher risk of pneumonia during the later stages of the disease. 50% of affected patients live at least three or more years after diagnosis; 20% live five years or more; and up to 10% will survive more than ten years. Generally, the outcome is fatal, resulting from respiratory insufficiency and failure.

Except for the hereditary cases that account for a minority of ALS cases, the cause is unknown, so there is no method for its prevention.