Amyotrophic lateral sclerosis (a-mi-oh-TROH-fik LAT-ur-ul skluh-ROH-sis), or ALS, is a serious neurological disease that causes muscle weakness, disability and eventually death. ALS is often called Lou Gehrig's disease, after the famous baseball player who was diagnosed with it in 1939. In the U.S., ALS and motor neuron disease (MND) are sometimes used interchangeably.
Worldwide, ALS occurs in 1 to 3 people per 100,000. In the vast majority of cases — 90 to 95 percent — doctors don't yet know why ALS occurs. About 5 to 10 percent of ALS cases are inherited.
ALS often begins with muscle twitching and weakness in an arm or leg, or with slurring of speech. Eventually, ALS affects your ability to control the muscles needed to move, speak, eat and breathe.
Early signs and symptoms of ALS include:
- Difficulty lifting the front part of your foot and toes (footdrop)
- Weakness in your leg, feet or ankles
- Hand weakness or clumsiness
- Slurring of speech or trouble swallowing
- Muscle cramps and twitching in your arms, shoulders and tongue
The disease frequently begins in your hands, feet or limbs, and then spreads to other parts of your body. As the disease advances, your muscles become progressively weaker until they're paralyzed. It eventually affects chewing, swallowing, speaking and breathing.
In ALS, the nerve cells that control the movement of your muscles gradually die, so your muscles progressively weaken and begin to waste away. Up to 1 in 10 cases of ALS is inherited. But the remainder appear to occur randomly.
Researchers are studying several possible causes of ALS, including:
- Gene mutation. Various genetic mutations can lead to inherited forms of ALS, which appear nearly identical to the non-inherited forms.
- Chemical imbalance. People who have ALS typically have higher than normal levels of glutamate, a chemical messenger in the brain, around the nerve cells in their spinal fluid. Too much glutamate is known to be toxic to some nerve cells.
- Disorganized immune response. Sometimes a person's immune system begins attacking some of his or her body's own normal cells, and scientists have speculated that this may trigger the process that results in ALS.
- Protein mishandling. There's evidence that mishandled proteins within the nerve cells can lead to a gradual accumulation of abnormal forms of these proteins in the cells, eventually causing the nerve cells to die.
Established risk factors for ALS include:
- Heredity. Up to 10 percent of the people who have ALS inherited it from their parents. If you have this type of ALS, your children have a 50-50 chance of developing the disease.
- Age. ALS most commonly occurs in people between the ages of 40 and 60.
- Sex. Before the age of 65, slightly more men than women develop ALS. This sex difference disappears after age 70.
It may be that ALS, similar to other diseases, is triggered by certain environmental factors in people who already carry a genetic predisposition to the disease. For example, some studies examining the entire human genome (genome-wide association studies) found numerous genetic variations that people with ALS held in common, and that might make a person more susceptible to ALS.
Environmental factors under study that may modify a person's individual risk of ALS include:
- Smoking. Smoking cigarettes appears to increase a person's risk of ALS to almost twice the risk of nonsmokers. The more years spent smoking, the greater the risk. On the other hand, quitting smoking can eventually lower this increased risk to that of a nonsmoker.
- Lead exposure. Some evidence suggests that exposure to lead in the workplace may be associated with the development of ALS.
- Military service. Recent studies indicate that people who have served in the military are at higher risk of ALS. Exactly what about military service may trigger the development of ALS is uncertain, but it may include exposure to certain metals or chemicals, traumatic injuries, viral infections and intense exertion.
As the disease progresses, people with ALS experience one or more of the following complications:
ALS eventually paralyzes the muscles needed to breathe. Some devices to assist your breathing are worn only at night and are similar to devices used by people who have sleep apnea (for example, continuous positive airway pressure, or CPAP, masks). In the latter stages of ALS, some people choose to have a tracheostomy — a surgically-created hole at the front of the neck leading to the windpipe (trachea) — to enable the 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, usually within three to five years after symptoms begin.
When the muscles that control swallowing are affected, people with ALS can develop malnutrition and dehydration. They are also at higher risk of aspirating food, liquids or secretions into the lungs, which can cause pneumonia. A feeding tube can reduce these risks.
Some people with ALS experience problems with memory and making decisions, and some are eventually diagnosed with a form of dementia called frontotemporal dementia.
Preparing for your appointment
If you're having some of the early signs and symptoms of a neuromuscular disease such as ALS, you might first consult your family doctor, who will listen to your description of symptoms and do an initial physical examination. Then your doctor will probably refer you to a neurologist for further evaluation.
What you can do
Once you're under the care of a neurologist, it may still take time to establish the diagnosis. In fact, most studies have shown that on average, it takes up to a year to get a formal diagnosis of ALS. If you've been referred to an academic medical center, your evaluation may involve a team of neurologists and other doctors specializing in different aspects of motor neuron disease.
Although a thorough workup usually means you're getting top-notch care, the process can be stressful and frustrating unless your medical team keeps you informed. These strategies may 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 the time and circumstances each time you notice problems with walking, hand coordination, speech, swallowing or involuntary muscle movements. Your observations may reveal a pattern pointing to a specific diagnosis.
- Find one 'go-to' neurologist or neurology nurse specialist. If you see more than one doctor and visit more than one department, you need a coordinator who's familiar with your overall situation, willing to answer your questions and prepared to make your concerns known to the other people involved in your care. Your family doctor or the neurologist who orders your tests and subspecialty consultations may be the best candidate, but in some institutions, care coordination is the responsibility of a nurse, social worker or case manager.
What to expect from your doctor
Your family doctor will carefully review your family's medical history and your signs and symptoms. Your neurologist and your family doctor may both check your neurological health by testing:
- Muscle strength
- Muscle tone
- Senses of touch and sight
Tests and diagnosis
Amyotrophic lateral sclerosis is difficult to diagnose early because it may appear similar to several other neurological diseases. Tests to rule out other conditions may include:
- Electromyogram. This test measures the tiny electrical discharges produced in muscles. A fine wire electrode is inserted into the muscles that your doctor wants to study. An instrument records the electrical activity in your muscle as you rest and contract the muscle. Generally, this test is mildly uncomfortable.
- Nerve conduction study. For this test, electrodes are attached to your skin above the nerve or muscle to be studied. A small shock, which may feel like a twinge or spasm, is passed through the nerve to measure the strength and speed of nerve signals.
- MRI. Using radio waves and a powerful magnetic field, MRI can produce detailed images of your brain and spinal cord. It involves lying on a movable bed that slides into a tube-shaped machine that makes loud thumping and banging noises during operation. Some people feel uncomfortable in the confined space.
- Blood and urine tests. Analyzing samples of your blood and urine in the laboratory may help your doctor eliminate other possible causes of your signs and symptoms.
- Muscle biopsy. If your doctor believes you may have a muscle disease rather than ALS, you may undergo a muscle biopsy. In this procedure, a small portion of muscle is removed while you're under local anesthesia and is sent to a lab for analysis.
Treatments and drugs
Because there's no reversing the course of amyotrophic lateral sclerosis, treatments mainly involve efforts to slow the progression of symptoms and make you more comfortable and independent.
The drug riluzole (Rilutek) is the first and only medication approved by the Food and Drug Administration for slowing ALS. The drug appears to slow the disease's progression in some people, perhaps by reducing levels of glutamate — a chemical messenger in the brain that's often present in higher levels in people with ALS.
Your doctor may also prescribe medications to provide relief from:
- Muscle cramps
- Excessive salivation
- Excessive phlegm
- Physical therapy. A physical therapist can recommend low-impact exercises to maintain your cardiovascular fitness, muscle strength and range of motion as long as possible, helping you preserve a sense of independence. Regular exercise can also help improve your sense of well-being.
- Occupational therapy. An occupational therapist can help you become accustomed to a brace, walker or wheelchair and may be able to suggest devices such as ramps that make it easier for you to get around.
- Speech therapy. Because ALS affects the muscles you use to speak, communication becomes an issue as the disease progresses. A speech therapist can help teach adaptive techniques to make your speech more clearly understood or help you explore alternative methods of communication, such as an alphabet board or simple pen and paper. Later in the disease, a speech therapist can recommend devices such as speech synthesizers and computer-based equipment that may help you communicate. Ask your therapist about the possibility of borrowing or renting these devices.
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 rob you of your mobility and independence can be difficult to absorb. If you are newly diagnosed, you and your family will likely experience a period of mourning and grief.
- Be hopeful. Some people with amyotrophic lateral sclerosis live much longer than the three to five years typically 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 rich, 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 may find comfort in sharing your concerns in a support group with others who have ALS. Your family members and friends helping with your care also may benefit from a support group of others who care for people with amyotrophic lateral sclerosis. 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. And you can determine where you want to spend your final days. This can help you and your loved ones put to rest certain anxieties about the future.