Amyotrophic lateral sclerosis (a-my-o-TROE-fik LAT-ur-ul skluh-ROE-sis), or ALS, is a progressive nervous system disease that affects nerve cells in the brain and spinal cord, causing loss of muscle control.
ALS is often called Lou Gehrig's disease, after the baseball player who was diagnosed with it. Doctors usually don't know why ALS occurs. Some cases are inherited.
ALS often begins with muscle twitching and weakness in a limb, or slurred speech. Eventually, ALS affects control of the muscles needed to move, speak, eat and breathe. There is no cure for this fatal disease.
Symptoms
Signs and symptoms of ALS vary greatly from person to person, depending on which neurons are affected. It generally begins with muscle weakness that spreads and gets worse over time. Signs and symptoms might include:
- Difficulty walking or doing normal daily activities
- Tripping and falling
- Weakness in your legs, feet or ankles
- Hand weakness or clumsiness
- Slurred speech or trouble swallowing
- Muscle cramps and twitching in your arms, shoulders and tongue
- Inappropriate crying, laughing or yawning
- Cognitive and behavioral changes
ALS often starts in the hands, feet or limbs, and then spreads to other parts of your body. As the disease advances and nerve cells are destroyed, your muscles get weaker. This eventually affects chewing, swallowing, speaking and breathing.
There's generally no pain in the early stages of ALS, and pain is uncommon in the later stages. ALS doesn't usually affect your bladder control or your senses.
Causes
ALS affects the nerve cells that control voluntary muscle movements such as walking and talking (motor neurons). ALS causes the motor neurons to gradually deteriorate, and then die. Motor neurons extend from the brain to the spinal cord to muscles throughout the body. When motor neurons are damaged, they stop sending messages to the muscles, so the muscles can't function.
ALS is inherited in 5% to 10% of people. For the rest, the cause isn't known.
Researchers continue to study possible causes of ALS. Most theories center on a complex interaction between genetic and environmental factors.
Risk factors
Established risk factors for ALS include:
- Heredity. Five to 10 percent of the people with ALS inherited it (familial ALS). In most people with familial ALS, their children have a 50-50 chance of developing the disease.
- Age. ALS risk increases with age, and is most common between the ages of 40 and the mid-60s.
- Sex. Before the age of 65, slightly more men than women develop ALS. This sex difference disappears after age 70.
- Genetics. Some studies examining the entire human genome found many similarities in the genetic variations of people with familial ALS and some people with noninherited ALS. These genetic variations might make people more susceptible to ALS.
Environmental factors, such as the following, might trigger ALS.
- 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 might be linked to ALS. Much study has been done, but no single agent or chemical has been consistently associated with ALS.
- Military service. Studies indicate that people who have served in the military are at higher risk of ALS. It's unclear what about military service might trigger the development of ALS. It might include exposure to certain metals or chemicals, traumatic injuries, viral infections, and intense exertion.
Complications
As the disease progresses, ALS causes complications, such as:
Breathing problems
Over time, ALS paralyzes the muscles you use to breathe. You might need a device to help you breathe at night, similar to what someone with sleep apnea might wear. For example, you may be given a bilevel positive airway pressure (BiPAP) device to help with your breathing at night. This type of device supports your breathing through a mask worn over your nose, your mouth or both.
Some people with advanced ALS choose to have a tracheostomy — a surgically created hole at the front of the neck leading to the windpipe (trachea) — for full-time use of a respirator that inflates and deflates their lungs.
The most common cause of death for people with ALS is respiratory failure. On average, death occurs within 3 to 5 years after symptoms begin. However, some people with ALS live 10 or more years.
Speaking problems
Most people with ALS develop trouble speaking. This usually starts as occasional, mild slurring of words, but becomes more severe. Speech eventually becomes difficult for others to understand, and people with ALS often rely on other communication technologies to communicate.
Eating problems
People with ALS can develop malnutrition and dehydration from damage to the muscles that control swallowing. They are also at higher risk of getting food, liquids or saliva into the lungs, which can cause pneumonia. A feeding tube can reduce these risks and ensure proper hydration and nutrition.
Dementia
Some people with ALS have problems with memory and decision-making, and some are eventually diagnosed with a form of dementia called frontotemporal dementia.
Diagnosis
Amyotrophic lateral sclerosis is difficult to diagnose early because it can mimic other neurological diseases. Tests to rule out other conditions might include:
-
Electromyogram (EMG). Your doctor inserts a needle electrode through your skin into various muscles. The test evaluates the electrical activity of your muscles when they contract and when they're at rest.
Abnormalities in muscles seen in an EMG can help doctors diagnose or rule out ALS. An EMG can also help guide your exercise therapy.
- Nerve conduction study. This study measures your nerves' ability to send impulses to muscles in different areas of your body. This test can determine if you have nerve damage or certain muscle or nerve diseases.
- MRI. Using radio waves and a powerful magnetic field, an MRI produces detailed images of your brain and spinal cord. An MRI can reveal spinal cord tumors, herniated disks in your neck or other conditions that might be causing your symptoms.
- Blood and urine tests. Analyzing samples of your blood and urine in the laboratory might help your doctor eliminate other possible causes of your signs and symptoms.
- Spinal tap (lumbar puncture). This involves removing a sample of your spinal fluid for laboratory testing using a small needle inserted between two vertebrae in your lower back.
- Muscle biopsy. If your doctor believes you may have a muscle disease rather than ALS, you might undergo a muscle biopsy. While you're under local anesthesia, a small portion of your muscle is removed and sent to a lab for analysis.
Treatment
Treatments can't reverse the damage of amyotrophic lateral sclerosis, but they can slow the progression of symptoms, prevent complications, and make you more comfortable and independent.
You might need an integrated team of doctors trained in many areas and other health care professionals to provide your care. This might prolong your survival and improve your quality of life.
Your team will help you select the right treatments for you. You have the right to choose or refuse any of the treatments suggested.
Medications
The Food and Drug Administration has approved two drugs for treating ALS:
- Riluzole (Rilutek). Taken orally, this drug has been shown to increase life expectancy by 3 to 6 months. It can cause side effects such as dizziness, gastrointestinal conditions and liver function changes. Your doctor will monitor your blood counts and liver functions while you're on the drug.
- Edaravone (Radicava). This drug, given by intravenous infusion, has been shown to reduce the decline in daily functioning. Its effect on life span isn't yet known. Side effects can include bruising, headache and shortness of breath. This medication is given daily for two weeks a month.
Your doctor might also prescribe medications to provide relief from other symptoms, including:
- Muscle cramps and spasms
- Constipation
- Fatigue
- Excessive saliva and phlegm
- Pain
- Depression
- Sleep problems
- Uncontrolled outbursts of laughing or crying
Therapies
-
Breathing care. You'll eventually have more difficulty breathing as your muscles weaken. Doctors might test your breathing regularly and provide you with devices to assist your breathing at night.
You can choose mechanical ventilation to help you breathe. Doctors insert a tube in a surgically created hole at the front of your neck leading to your windpipe (tracheostomy) that connects to a respirator.
-
Physical therapy. A physical therapist can address pain, walking, mobility, bracing and equipment needs that help you stay independent. Practicing low-impact exercises can help maintain your cardiovascular fitness, muscle strength and range of motion for as long as possible.
Regular exercise can also help improve your sense of well-being. Appropriate stretching can help prevent pain and help your muscles function at their best.
A physical therapist can also help you adjust to a brace, walker or wheelchair and might suggest devices such as ramps that make it easier for you to get around.
-
Occupational therapy. An occupational therapist can help you find ways to remain independent despite hand and arm weakness. Adaptive equipment can help you perform activities such as dressing, grooming, eating and bathing.
An occupational therapist can also help you modify your home to allow accessibility if you have trouble walking safely.
-
Speech therapy. A speech therapist can teach you adaptive techniques to make your speech more understandable. Speech therapists can also help you explore other methods of communication, such as an alphabet board or pen and paper.
Ask your therapist about the possibility of borrowing or renting devices such as tablet computers with text-to-speech applications or computer-based equipment with synthesized speech that can help you communicate.
- Nutritional support. Your team will work with you and your family members to ensure you're eating foods that are easier to swallow and meet your nutritional needs. You might eventually need a feeding tube.
- Psychological and social support. Your team might include a social worker to help with financial issues, insurance, and getting equipment and paying for devices you need. Psychologists, social workers and others may provide emotional support for you and your family.
Potential future treatments
Clinical studies on promising medications and treatments are occurring for ALS all the time.
Coping and support
Learning you have ALS can be devastating. The following tips may help you and your family cope:
- Take time to grieve. The news that you have a fatal condition that will reduce your mobility and independence is difficult. You and your family will likely go through a period of mourning and grief after diagnosis.
- Be hopeful. Your team will help you focus on your abilities and healthy living. Some people with ALS live much longer than the 3 to 5 years usually associated with this condition. Some live 10 years or more. Maintaining an optimistic outlook can help improve quality of life for people with ALS.
- Think beyond the physical changes. Many people with amyotrophic lateral sclerosis lead rewarding lives despite physical limitations. Try to think of ALS as only one part of your life, not your entire identity.
- Join a support group. You might find comfort in a support group with others who have ALS. Loved ones helping with your care also might benefit from a support group of other ALS caregivers. Find support groups in your area by talking to your doctor or by contacting the ALS Association.
-
Make decisions now about your future medical care. Planning for the future allows you to be in control of decisions about your life and your care. With the help of your doctor, hospice nurse or social worker, you can decide whether you want certain life-extending procedures.
You can also decide where you want to spend your final days. You might consider hospice care options. Planning for the future can help you and your loved ones calm anxieties.
Preparing for an appointment
You might first consult your family doctor about signs and symptoms of ALS. Then your doctor will probably refer you to a doctor trained in nervous system conditions (neurologist) for further evaluation.
What you can do
You might need many tests to diagnose your condition, which can be stressful and frustrating. These strategies might give you a greater sense of control.
- Keep a symptom diary. Before you see a neurologist, start using a calendar or notebook to jot down when and how you notice problems with walking, hand coordination, speech, swallowing or involuntary muscle movements. Your notes might show a pattern that's helpful for your diagnosis.
- Find a neurologist and care team. An integrated care team led by your neurologist usually is most appropriate for your ALS care. Your team should communicate with each other and be familiar with your needs.
What to expect from your doctor
Your family doctor will review your family's medical history and your signs and symptoms. Your neurologist and your family doctor might conduct a physical and neurological examination, which might include testing the following:
- Reflexes
- Muscle strength
- Muscle tone
- Senses of touch and sight
- Coordination
- Balance
Copyright © 1998-2024 Mayo Foundation for Medical Education and Research (MFMER). All rights reserved.