This leads to muscle weakness and changes in how the body works. In the later stages, amyotrophic lateral sclerosis (ALS) affects the nerves that control breathing, and this can be fatal.
ALS is the most common type of motor neuron disease (MND). It is sometimes called Lou Gehrig's disease, after the famous baseball player who had the condition. The 2014 Ice Bucket Challenge aimed to raise awareness and funds for research.
The Centers for Disease Control and Prevention (CDC) estimate that between 14,500 and 15,000 people in the United States (U.S.) had ALS in 2016, with around 5,000 people receiving a diagnosis annually. Worldwide, it is thought to affect between 2 and 5 people in every 100,000.
Most people with ALS will live for 3 to 5 years after first experiencing symptoms, but around 10 percent of patients will live for another 10 years or longer.
There is no cure, but treatment can relieve symptoms and improve quality of life.
Contents of this article:
Here are some key points about ALS. More detail is in the main article.
- ALS affects nerve cells in the brain and spinal cord, leading to muscle weakness, a loss of motor function, paralysis, breathing problems, and, eventually, death.
- Most people with ALS will live between 3 and 5 years after symptoms appear.
- The exact cause is unknown, but environmental and genetic factors may be involved.
- There is currently no cure, and treatment aims to relieve symptoms, provide social and emotional support, and possibly slow disease progression.
What is ALS?
Adaptive equipment can help people with ALS to stay mobile.
ALS is a kind of MND. It attacks the nerve cells that are used in voluntary muscle actions, known as motor neurons. These are actions that we can control, such as those in the arms, face, and legs.
Motor neurons are found in the brain and spinal cord. As ALS progresses, these cells degenerate and die. They stop sending messages to muscles. The brain can no longer control voluntary movement, and the muscles weaken and waste away.
As ALS progresses, it affects all the voluntary muscles. The person can no longer control their arms, face, and legs. In time, the inability to breathe unsupported can lead to respiratory failure.
Half of all people with ALS will live for 3 years or more after diagnosis, but some live for longer. Around 20 percent of people will live 5 years or more after diagnosis, 10 percent will live for 10 years or more, and 5 percent will live for 20 years.
Steven Hawking, the famous physicist, received a diagnosis of ALS aged 21 years. Now well over 70 years old, he remains a leader in the field of science.
Causes and types
It is unclear exactly what causes ALS. There are different types, according to their signs and symptoms and whether or not there is a clear genetic association.
ALS can be sporadic or familial.
Sporadic ALS occurs randomly, and it accounts for 90 to 95 percent of cases. There is no clear risk factor or cause.
Familial ALS is inherited. Around 5 to 10 percent of cases are familial. The child of a person with ALS will have a 50 percent chance of developing the condition. Rarely, it can affect a person in their teens. Researchers are investigating which genes are involved.
Other possible causes of ALS include:
- Disorganized immune response: The immune system may attack some of the body's cells, possibly killing nerve cells.
- Chemical imbalance: People with ALS often have higher levels of glutamate, a chemical messenger in the brain, near the motor neurons. Glutamate in high quantities is known to be toxic to nerve cells.
- Mishandling of proteins: If proteins are not processed correctly by nerve cells, abnormal proteins could potentially accumulate and cause the nerve cells to die.
Possible environmental factors
Environmental factors may also play a role.
One study has reported that military personnel deployed in the Gulf region during the 1991 war were more likely to develop ALS than military personnel deployed elsewhere.
Some possible links have been found between ALS and exposure to:
- mechanical or electrical trauma
- military service
- high levels of exercise
- high levels of agricultural chemicals
- high levels of a variety of heavy metals
However, there is no conclusive evidence that specific lifestyle changes can decrease the risk.
Signs and symptoms
The symptoms of ALS usually appear when a person is in their late 50s or early 60s, but it can happen at other ages.
Progression varies between individuals. In the early stages, signs and symptoms may be barely noticeable, but the weakness becomes more visible over time.
Common symptoms include:
- difficulty carrying out daily activities, including walking
- increased clumsiness
- weakness in the feet, hands, legs, and ankles
- cramping and twitching in the arms, shoulders, or tongue
- difficulty maintaining good posture and holding the head up
- uncontrolled outbursts of laughing or crying, known as emotional lability
- cognitive changes
- slurring of speech and difficulty with voice projection
- problems with saliva, and mucus
- difficulty breathing and swallowing, in the later stages
Progressive muscle weakness occurs in all cases of ALS, but this may not be the first indication of the condition.
Early symptoms often include clumsiness, abnormal limb fatigue, muscle cramps and twitches, and slurred speech. Symptoms will spread to all parts of the body as ALS progresses.
Some people may have problems with decision-making and memory, eventually leading to a form of dementia called frontotemporal dementia.
Emotional lability can cause fluctuations in mood and emotional response.
No single test can diagnose ALS, so diagnosis is based on symptoms and the results of tests to rule out other conditions with similar symptoms.
Tests that may help diagnose ALS are:
- electromyography (EMG), which detects electrical energy in muscles
- nerve conduction study (NCS), which tests how well the nerves send signals
These tests can help rule out peripheral neuropathy, or peripheral nerve damage, and myopathy, or muscle disease.
Further tests to rule out other conditions may include blood and urine tests and a muscle biopsy.
If there are symptoms in both the upper and lower motor neurons, ALS may be present.
Upper motor neuron symptoms include stiffness and resistance to movement in the muscles and brisk reflexes. Lower motor neuron symptoms include weakness, muscle atrophy, and twitching.
Treatment and prevention
There is no cure for ALS, so treatment aims to alleviate symptoms, prevent unnecessary complications, and slow the rate of disease progression.
ALS can cause a range of physical, mental, and social changes, so a team of specialists will often help patients manage their symptoms and care, improve their qualify of life, and prolong survival.
Riluzole (Rilutek) was approved for ALS treatment by the Food and Drug Administration (FDA) in 1995, and it appears to slow the progression of the disease. It may work by reducing the body's levels of glutamate, an excitotoxin that has been linked to neuronal damage.
In May 2017, Radicava (Edaravone) was approved to treat ALS. It may slow the decline in physical function by one third.
A number of research projects are looking at ways to use new and existing drugs to treat different aspects of ALS. Doctors can also prescribe medications to treat the different symptoms.
Physical therapy can help people with ALS manage pain and address mobility issues.
A physical therapist can provide help and information with:
- low-impact exercises to enhance cardiovascular fitness and overall well-being
- mobility aids, such as walkers and wheelchairs
- devices to make life easier, such as ramps
Occupational therapy can help a patient maintain their independence for longer by:
- helping patients choose adaptive equipment and assistive technologies to help them keep up their daily routines
- train them in ways to compensate for hand and arm weaknesses
Breathing therapy may be needed in time, as the respiratory muscles get weaker.
Breathing devices can help the patient breathe better at night. Some patients may need mechanical ventilation. One end of a tube is connected to a respirator, while the other end is inserted into the windpipe through a surgically-created hole in the neck, or tracheostomy.
Speech therapy is useful when ALS begins to make it harder to talk. Speech therapists can help by teaching adaptive techniques. Other methods of communication include writing and computer-based communications equipment.
Nutritional support is important, as difficulty with swallowing can make it hard to get enough nutrients. Nutritionists can advise on preparing nutritious meals that are easier to swallow. Suction devices and feeding tubes may help.
Tips for living with ALS
A number of tips may help people with ALS and their loved ones to adjust to their changing situation.
Keep in touch: Social contact is important. Stay in touch with friends and keep up with as many previous activities as possible. There may be a local or online support groups that can answer questions and offer insight through shared experiences.
Be practical: Have a bag ready with tissues, hand wipes, and easy-to-hold cutlery for going out. Register to get a disability placard for the car. Make adjustments at home, for example, a device to raise the toilet seat.
Plan ahead: It can be hard when a loved one finds they can no longer do something they could do before, but foreseeing possible restrictions can help you be prepared for when they come.
Research financial help: As the disease progresses, treatment can become expensive. Find out if you are entitled to help through Social Security Disability, Medicare, Medicaid and Veteran Affairs benefits.
Arrange relief for caregivers: Arrange for a friend, relative, or caregiver to come and stay for a weekend or to take the person with ALS out for the day. Caregivers should make sure they look after their own health, as well as that of their loved one.
What you can do will depend to some extent on your finances, but local support groups can help people cope with the financial and emotional challenges involved with ALS, through advice or practical help.