ALS is a medical condition that affects the nervous system and impacts the nerve cells in the brain and spinal cord. ALS leads to loss of muscle control and progressively worsens over time.
ALS often begins with muscle twitching, weakness in an arm or leg, and difficulty swallowing or slurred speech. Eventually, ALS affects the control of muscles needed for movement, speech, eating, and breathing. There is no cure for this fatal disease.
Symptoms
ALS symptoms vary from person to person, and the symptoms differ depending on which nerve cells are affected. ALS generally begins with muscle weakness that spreads and worsens over time. Symptoms may include the following:
•Difficulty walking or performing usual daily activities.
• Tripping and falling.
•Weakness in the legs, feet, or ankles.
•Weakness in the hands or difficulty controlling their movement.
• Slurred speech or difficulties with swallowing.
•Weakness associated with muscle spasms and twitching in the arms, shoulders, and tongue.
• Inappropriate crying, laughing, or yawning.
• Changes in thinking or behavior.
ALS often begins in the hands, feet, arms, or legs, then spreads to other parts of the body. Muscles weaken as more nerve cells die, eventually affecting chewing, swallowing, speaking, and breathing.
Generally, there is no pain during the early stages of ALS, and pain is not commonly felt in the later stages either. ALS typically does not affect bladder control and usually does not impact the senses, such as the ability to taste, smell, touch, or hear.
Causes
ALS affects the nerve cells that control voluntary muscle movements, such as walking and speaking. These nerve cells are called "motor neurons." Motor neurons are divided into two groups. The first group extends from the brain to the spinal cord and then to the muscles throughout the body, known as upper motor neurons. The second group extends from the spinal cord to the muscles, also throughout the body, known as lower motor neurons.
ALS causes progressive damage to both groups of motor neurons, leading to their death. When motor neurons are damaged, they stop sending messages to the muscles. As a result, the muscles are unable to function.
A genetic cause can be identified in about 10% of ALS patients, while the cause in the remaining cases is unknown.
ALS causes progressive damage to both groups of motor neurons, leading to their death. When motor neurons are damaged, they stop sending messages to the muscles. As a result, the muscles are unable to function.
Risk factors
Potential risk factors for ALS include:
• Genetic traits. About 10% of ALS patients are affected when a potentially harmful gene is passed down from a family member. This is known as familial ALS. The likelihood of inheriting the gene is 50% in the children of most people with familial ALS.
• Age. The risk of developing ALS increases with age, peaking around 75 years. ALS is more common between the ages of sixty and mid-eighties.
• Gender. Men are slightly more likely than women to develop ALS before the age of 65. However, this gender difference diminishes after the age of 70.
Certain environmental factors are associated with an increased risk of developing ALS, including:
Smoking. Evidence supports the hypothesis that smoking is an environmental risk factor associated with ALS. It appears that women who smoke are at a higher risk, especially after menopause.
• Exposure to environmental toxins. Some evidence suggests that exposure to lead or other substances in the workplace or home may be linked to ALS. Several studies have been conducted, but no consistent association has been found between a specific factor or chemical and the development of ALS.
Complications
As the disease progresses, ALS causes complications, such as:
Respiratory issues.
Over time, ALS leads to weakness in the muscles that the body uses for breathing. Those affected by ALS may need a device, such as a ventilator equipped with a mask, to assist them with breathing at night, similar to the device worn by those with sleep apnea. This type of device supports the breathing process by having the person wear a mask over the nose, mouth, or both.
Some individuals with advanced ALS choose to undergo a tracheostomy procedure, which involves creating a surgical opening in the front of the neck that leads to the trachea. A ventilator may work more effectively with a tracheostomy than with a mask.
Speech difficulties.
Most individuals with ALS experience weakness in the muscles used for speech. This typically begins with slurred speech and occasional word mixing. It can progress to difficulties in speaking clearly, to the point where others may struggle to understand what the person is saying. Alternative communication methods and techniques can be utilized.
Eating difficulties.
Patients with ALS may experience weakness in the muscles involved in swallowing, which can lead to malnutrition and dehydration. These patients also become more susceptible to food, liquids, or saliva entering the lungs, which may result in pneumonia. A feeding tube can help reduce these risks and ensure proper nutrition and hydration.
Dementia.
Some individuals with ALS experience language and decision-making difficulties. Some are eventually diagnosed with a type of dementia known as frontotemporal dementia.
