- What Is It
- Risk Factors
- Related Resources
ALS affects the muscles under voluntary control, causing the loss of strength and ability to eat, speak, grasp things, move, and even breathe. When symptoms begin in the arms or legs, it is referred to as limb onset ALS, and when it causes speech or swallowing problems as initial signs, it is called bulbar onset ALS.
ALS was also known as Lou Gehrig’s disease, following the retirement of a famous ballplayer Lou Gehrig in the 1940s due to the disease.
What is ALS?
Amyotrophic lateral sclerosis (ALS) is a progressive neurological disease that is caused by the gradual deterioration and death of motor neurons. Motor neurons are nerve cells extending from the brain to the spinal cord and muscles throughout the body.
When motor neurons degenerate, they stop sending messages to the muscles and cause them to gradually weaken, leading to fasciculations (twitching) and atrophy (wasting away of muscles). Eventually, the brain loses the ability to initiate and control voluntary movements and a decline in the ability to talk, write, swallow, and breathe.
In most cases, ALS affects both upper and lower motor neurons:
- Upper motor neurons: Present in the brain and spinal cord and are responsible for sending signals to the lower motor neurons
- Lower motor neurons: Present in the brain stem (lower part of the brain) and spinal cord and are responsible for receiving instructions from the upper motor neurons and forwarding them to the muscles
A person may experience different symptoms depending on whether upper or lower motor neurons are affected. Upper motor neuron affection usually causes muscle stiffening, whereas lower motor neuron affection causes loss of muscle tone.
What are different types of ALS?
- Classical amyotrophic lateral sclerosis (ALS):
- Most common type that affects more than two-thirds of people with ALS
- Both the upper and lower motor neurons decline
- Progressive bulbar palsy:
- Affects about 25% of people with ALS.
- Starts with difficulty speaking, chewing, and swallowing caused by a breakdown of the upper and lower motor neurons in the mouth and throat.
- Progressive muscular atrophy:
- Affects only the lower motor neurons
- Primary lateral sclerosis:
- The rarest type of ALS
- Only the upper motor neurons decline
What causes ALS?
The exact cause of amyotrophic lateral sclerosis (ALS) is unknown; however, scientific evidence suggests that both genetics and environment play a role in motor neuron degeneration and ALS development:
- Genetics: The National Institute of Neurological Disorders and Stroke discovered that mutations in the SOD1 gene were associated with cases of familial ALS.
- Environmental factors: Studies have shown that environmental factors have an effect on the development or progression of the disease. These factors include exposure to toxic or infectious agents, viruses, physical trauma, diet, behavior, and occupational factors.
ALS is divided into two categories:
- Sporadic ALS: About 90%-95% of ALS cases are sporadic, which is not tied to any clear risk factor or family history of the disease.
- Familial (genetic) ALS: About 5%-10% of all ALS cases are familial, which means that an individual inherits the disease from a parent due to genetic mutations.
What are the risk factors for ALS?
Amyotrophic lateral sclerosis (ALS) affects people of all ethnicities. Risk factors for ALS include:
- Age: Although the disease can occur at any age, symptoms most commonly develop between the ages of 55 and 75 years.
- Gender: Men are slightly more likely to develop ALS than women.
- Ethnicity: Caucasians and non-Hispanics are most likely to develop the disease.
Some studies report that military veterans are about 1.5 to 2 times more likely to develop ALS because they are exposed to lead, pesticides, and other environmental toxins during their service.
What are the symptoms of ALS?
The onset of amyotrophic lateral sclerosis (ALS) is subtle and the symptoms are often overlooked. Gradually, these symptoms develop into obvious weakness or atrophy.
Early symptoms include:
- Muscle weakness or stiffness that affects the arm, leg, neck, or diaphragm
- Muscle twitches in the arm, leg, shoulder, or tongue
- Muscle cramps
- Spasticity (tight and stiff muscles)
- Slurred and nasal speech
- Difficulty chewing or swallowing
- Gradual loss of strength and ability to speak, eat, move, and even breathe
The disease progresses over 3-5 years. As the disease progresses, muscle weakness and atrophy spread to other parts of the body, leading to:
- Difficulty moving
- Dysphagia (difficulty swallowing)
- Dysarthria (difficulty speaking or forming words)
- Dyspnea (difficulty breathing)
Because individuals with ALS have difficulty swallowing and chewing food and a faster calorie-burning rate, they tend to lose weight rapidly and become malnourished. People with ALS eventually may lose the ability to breathe on their own and must depend on a ventilator.
Pulmonary problems with ALS include:
- Shortness of breath, even at rest
- Weak cough
- Difficulty clearing throat and lungs
- Increased salivation
- Inability to lie flat in bed
- Repeated chest infections and pneumonia
- Respiratory failure
Some individuals with ALS may develop painful neuropathy (nerve disease or damage) or dementia over time. Most people with ALS die from respiratory failure.
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How is ALS diagnosed?
There is no single test that provides a definitive diagnosis of amyotrophic lateral sclerosis (ALS). Diagnosis is primarily based on a detailed history of the symptoms observed by a physician during physical examination, a review of a complete medical history, and a series of tests to rule out other diseases.
In addition to blood and urine tests, the following tests may be ordered:
- Neurologic examination: Tests for reflexes and analyzes symptoms such as muscle weakness, muscle wasting, and spasticity
- Electromyography: Assesses the electrical activity of muscle fibers and nerves
- Nerve conduction study: Measures the nerve’s ability to send signals to the muscle
- Magnetic resonance imaging: Uses a magnetic field and radio waves to produce detailed images of the brain and spinal cord
- Muscle biopsy: Analyzes tissue samples of the muscles or nerves
- Spinal fluid test: Analyzes spinal fluid to help diagnose brain and spinal cord problems
How is ALS treated?
Currently, there is no cure for amyotrophic lateral sclerosis (ALS) and no effective treatment to stop or reverse the progression of the disease. Treatments may include:
- Medications: FDA-approved drugs to treat ALS include Rilutek (riluzole) and Radicava (edaravone); may also include medications to help manage symptoms of muscle cramps, stiffness, excess, saliva, and phlegm
- Physical and occupational therapy: To ease discomfort from stiff muscles, cramps, and fluid retention
- Nutritional support: To ensure a healthy, balanced diet
- Speech therapy: Communication training to help maintain verbal communication
- Assistive devices: Splints, braces, bars, and devices to help stay the person independent
- Special equipment: Wheelchairs and electric beds to help the person function independently
Health Solutions From Our Sponsors
Amyotrophic Lateral Sclerosis (ALS) Fact Sheet. NIH: https://www.ninds.nih.gov/amyotrophic-lateral-sclerosis-als-fact-sheet
Amyotrophic Lateral Sclerosis (ALS). Cleveland Clinic: https://my.clevelandclinic.org/health/diseases/16729-amyotrophic-lateral-sclerosis-als
Amyotrophic Lateral Sclerosis (ALS). Johns Hopkins Medicine: https://www.hopkinsmedicine.org/health/conditions-and-diseases/amyotrophic-lateral-sclerosis-als
Understanding ALS. ALS Association: https://www.als.org/understanding-als
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MS (Multiple Sclerosis) vs. ALS (Amyotrophic Lateral Sclerosis)ALS (amyotrophic lateral sclerosis, Lou Gehrig's disease) and MS (multiple sclerosis) are both diseases of the nervous system (neurodegenerative). ALS is a disease in which the nerve cells in the body are attacked by the immune system, although it's not considered an autoimmune disease by some scientists. MS is an autoimmune disease in which the insulated covering of the nerves (myelin sheath) in the CNS (central nervous system) degenerate, or deteriorate.
Scientists don't know the exact cause of either problem. However, they have discovered that mutations in the gene that produces the SOD1 enzyme were associated with some cases of familial ALS. Scientists also theorize that multiple sclerosis may be caused by infection or vitamin D deficiency. ALS occurs between 50-70 years of age (the average age of occurrence ALS is 55), and mostly affects men. While MS occurs between 20-60 years of age, and mostly affects women. About 30,000 people in the US have ALS, and an average of 5,000 new diagnoses per year (that's about 15 new cases per week). Worldwide, MS affects more than 2.3 million people, with about 10,000 new cases diagnosed each year (that's about 200 new diagnoses per week).
Some of the signs and symptoms of both diseases include muscle weakness, muscle spasms, problems walking, fatigue, slurred speech, and problems swallowing. ALS signs and symptoms that are different from MS include problems holding the head upright, clumsiness, muscle cramps and twitches, problems holding objects, and uncontrollable periods of laughing or crying. MS signs and symptoms that are different from ALS include vision problems, vertigo and balance problems, sexual problems, memory problems, depression, mood swings, and digestive problems.
There is no cure for either disease, however the prognosis and life expectancy are different. Multiple sclerosis is not a fatal condition, while ALS progresses rapidly and leads to death.
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