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ALS is a condition that affects nerve cells, leading to eventual loss of control over muscle function. Symptoms include muscle twitches, cramps or weakness.
What is ALS?
Amyotrophic lateral sclerosis is also called ALS or Lou Gehrig's Disease named after the Hall of Fame baseball player whose career ended when he developed ALS. It is a degenerative disease that destroys nerve cells, which eventually leads to loss of control over muscle function. The cause of ALS is not known.
Symptoms include weakness; difficulty with speaking, swallowing, walking, or using the hands; and muscle cramps. It does not affect the senses or a person's mental ability.
ALS is progressive, meaning it worsens over time. There is no cure, but supportive care can keep the patient more comfortable and improve quality of life. Treatment involves medications to both slow the progression of the disease and ease the symptoms; respiratory therapy; physical therapy; occupational therapy; and psychological support.
Amyotrophic lateral sclerosis can't be cured but symptoms can be managed.
The onset of ALS can be very subtle. Symptoms are often overlooked at the onset, but gradually develop into muscle atrophy and weakness that manifests in obvious ways. The first sign of ALS may appear in the limbs. Patients may have difficulty with simple tasks such as buttoning a shirt, writing, or turning a key in a lock. In some cases, patients may experience problems running or walking ("limb onset" ALS). In other cases, symptoms begin with speech or swallowing problems ("bulbar onset" ALS). Some of the early symptoms of ALS include:
- Muscle twitches in the arm, leg, shoulder, or tongue
- Muscle cramps
- Tight and stiff muscles (spasticity)
- Muscle weakness affecting an arm, a leg, neck or diaphragm
- Slurred and nasal speech
- Difficulty swallowing or chewing
Regardless of where the ALS symptoms first appear, muscle weakness and atrophy spread to other parts of the body as the disease progresses and symptoms become very serious. Patients will likely develop:
- Breathing problems: Over time, people with ALS lose function of the muscles necessary for breathing. Many of these patients need devices to help them breathe at night and often will require a tracheostomy — a surgically created hole at the front of the neck leading to the windpipe (trachea) for full-time use of a device (mechanical ventilator) that manually inflates and deflates the lungs.
- Speaking problems: Most people with ALS will develop trouble speaking over time. This usually starts as occasional, mild slurring of words, but progresses to become more severe. Speech eventually becomes more difficult for others to understand, and people with ALS often rely on other communication technologies to communicate.
- Malnutrition: People with ALS develop weakness and atrophy of the muscles responsible for chewing and swallowing food, which results in difficulty maintaining adequate calories, rapid weight loss and malnutrition. They are also at higher risk of getting food, liquid, or saliva into the lungs, and require feeding tubes for proper hydration and nutrition.
- Depression: Because people with ALS usually retain their ability to perform higher mental processes, such as reasoning, remembering, understanding, and problem solving, they are aware of their progressive loss of function and can often become anxious and depressed.
The rate of disease progression varies from person to person but eventually individuals will not be able to stand or walk, get in or out of bed on their own, or use their hands and arms.
ALS is a rare, neurodegenerative disease that affects the nerve cells (neurons) of the brain and spinal cord. The word amyotrophic means "no muscle nourishment." ALS occurs when the motor nerve cells of the lateral spinal cord slowly die and, due to scarring (sclerosis), cannot provide adequate signals to the muscles of the body. This degeneration and loss of stimulation ultimately results in atrophy and loss of muscle control.
The reason why motor neurons begin to degenerate and die in people who have ALS is not completely understood. However, studies have identified two types of ALS:
- Familial ALS: Of all ALS cases, 5 to 10 percent are genetic, meaning they are inherited and passed down through families due to a mutation (change) in genes. Mutations in more than a dozen genes have been found to cause familial ALS. About 25 to 40 percent of all familial cases are caused by a defect in a gene that makes a protein very important to motor neurons. Another 12 to 20 percent of familial cases result from mutations in the gene needed to produce an enzyme important for destroying metabolites that can become toxic to cells.
- Sporadic ALS: On the other hand, the majority of ALS cases (90 percent or more) are considered sporadic. This means the disease seems to occur randomly with no family history of the disease and no clearly associated risk factors.
Main risk factors
Several established risk factors for ALS include:
- Age: Although ALS can happen at any age, symptoms most commonly develop between the ages of 55 and 75.
- Gender: Men are slightly more likely than women to develop ALS. However, this gender difference disappears with age.
- Race and ethnicity: Caucasians and non-Hispanics are more likely to develop the disease.
Other risk factors
Though not established as risk factors, environmental factors may trigger ALS. Some that may affect ALS risk include:
- Smoking: Smoking is the only likely environmental risk factor for ALS. The risk seems to be greatest for women, particularly after menopause.
- Environmental toxin exposure: Some evidence suggests that exposure to lead or other substances in the workplace or at home may be linked to ALS. Despite multiple studies investigating this interaction, no single agent or chemical has been consistently associated with ALS.
- Military service: According to the National Institutes of Health (NIH), some studies suggest that military veterans are about 1.5 to 2 times more likely to develop ALS. Although the reason for this is unclear, possible risk factors include exposure to lead, pesticides, and other environmental toxins. ALS is so common in veterans that it is recognized as a service-connected disease by the U.S. Department of Veterans Affairs.
There is no cure for ALS. However, there are treatments available that can help control symptoms and slow progression, prevent unnecessary complications, and make living with the disease easier. A multi-disciplinary team of healthcare professionals including neurologists work closely with patients with ALS in order to select appropriate treatments and options that work best for every individual.
Physical, occupational, speech and nutritional therapies are often the most important aspect of ALS treatment plans. They help patients maintain as much independence as possible despite the significant losses these patients experience. For example, a speech therapist can teach patients adaptive techniques for making speech more clearly understood or provide alternate methods of communication such as iPads or alphabet boards.
Two medications have been approved by the Food and Drug Administration for ALS treatment:
- Riluzole (Rilutek): This is a drug that has been shown to slow disease progression by reducing levels of a brain chemical called glutamate that is often present at higher levels in people with ALS. This drug is given in pill form.
- Edaravone (Radicava): This is a relatively new drug that has been shown to reduce the decline in activities of daily function (walking, eating, dressing, etc.) associated with ALS. This drug is given as an injection for 10 to 14 consecutive days each month.
When to seek further consultation
If you notice any symptoms that are characteristic of ALS, make an appointment with your physician promptly. This is especially important if there is a history of ALS in your family.
Questions your doctor may ask to diagnose
- Have you been feeling more tired than usual, lethargic or fatigued despite sleeping a normal amount?
- Any fever today or during the last week?
- How difficult is it to walk?
- Is your difficulty walking constant or come-and-go?
- How long has your walking difficulty been going on?
Self-diagnose with our free Buoy Assistant if you answer yes on any of these questions.
Dr. Gambrah-Lyles is a resident pediatrician at the Children's Hospital of Philadelphia. She is a graduate of the University of Pennsylvania Perelman School of Medicine (2019). She graduated cum laude and received her undergraduate degree in Biochemistry and Spanish from Washington University in St. Louis (2013). Her research explores the intersections between neurology, public health, and infectious disease. She has investigated nutrition and cerebral palsy in Botswana, and completed a year-long project in Brazil, researching growth and developmental outcomes of Zika virus infection in pediatric patients as a Doris Duke International Scholar. Dr. Gambrah-Lyles speaks four languages, loves staying active, and enjoys sharing her love for medicine through teaching and writing.
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