What You Need to Know About Amyotrophic Lateral Sclerosis

There's no cure for ALS—but there is hope.

What You Need to Know About Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that attacks the nerve cells controlling voluntary muscle movement in the brain and spinal cord. The ALS Association estimates that more than 16,000 Americans are affected. As ALS progresses, it kills the body’s nerve cells, resulting in weakened muscles, paralysis and ultimately, death. There is no cure.

The condition is sometimes called Lou Gehrig's disease, due to the widespread attention the baseball legend brought to ALS after his 1939 diagnosis. 

Symptoms and progression of ALS
Early symptoms occur in the muscles that are affected by ALS, but weakness and atrophy spread to the rest of the body as the disease progresses. Signs often begin with stiffness or weakness in one arm or leg, slurred speech or difficulty swallowing.

Patients diagnosed with ALS eventually lose the ability to walk, stand and use their extremities. As the disease progresses, patients require ventilator support to breathe. Due to weakening respiratory muscles, people affected by ALS often die of respiratory failure three to five years after the onset of the first symptom.

Despite this prognosis, about 10 percent of individuals diagnosed with ALS live for 10 or more years. Scientist Stephen Hawking, for example, survived more than five decades after being diagnosed with a rare form of ALS in 1963. He passed away in 2018.

How ALS is diagnosed
There isn’t a single test that can diagnose ALS. Doctors begin by assessing a patient’s symptoms and reviewing their medical history. They’ll next run a series of tests, like electromyography, which detects electrical activity in the muscles, and nerve conduction study, which assesses the nerves' ability to send a signal. These tests are performed to eliminate the possibility of other diseases.

Other tests include regular neurologic exams, which can help determine whether muscle weakness, atrophy and other symptoms associated with ALS are getting progressively worse. This progression would be an indicator of ALS.

A diagnosis of ALS requires signs of both upper and lower motor neuron damage that cannot be attributed to another illness. Upper motor neurons in the brain send messages to lower motor neurons in the spinal cord, which control the muscles—including those in your arms, face and throat—that perform essential functions, like walking and chewing.

ALS and its early symptoms can resemble symptoms of other diseases, including multiple sclerosis, West Nile virus and HIV. Because of these similarities, it’s often recommended that patients seek multiple opinions.

Why do people develop ALS?
The cause of ALS is still unknown, but more than a dozen genetic mutations have been linked to the disease. It’s unclear how these mutations lead to motor neuron degeneration, but research suggests it’s caused by cellular defects.

Researchers are also studying factors such as exposure to toxic agents, physical trauma and chemical imbalances in the body. People with ALS have increased levels of glutamate, a chemical messenger in the brain that’s toxic to nerve cells.

Treatments for ALS
There is no cure for ALS, but the U.S. Food and Drug Administration (FDA) has approved two drugs to slow disease progression: 

  • Rilutek (riluzole) was approved in 1995. It comes in pill form and appears to work in some patients, but does not reverse damage that has already occurred. Rilutek can prolong the life of some people with ALS by a few months. Tiglutik is a liquid form of riluzole, approved in September 2018.
  • Radicava (edaravone) was given the green light in May 2017. One clinical trial showed it slowed physical decline in ALS patients by 33 percent.

Other drugs and therapies may be prescribed to manage symptoms and keep patients functioning for as long as possible. These include speech and physical therapy, nutritional support and medications to manage pain, fatigue and muscle spasms.

The future of ALS
Scientists continue to study ALS, and new treatments are constantly in development. Awareness of the disease received a massive boost in 2014, when an ALS patient named Anthony Senerchia inspired the Ice Bucket Challenge, an online fundraising campaign. The rules were simple: Post a video of yourself dumping ice water over your head for donations, and encourage others to do the same.

The 17 million people who accepted the challenge ultimately raised more than $115 million for the ALS Association. Donations helped fund new treatments, care services, assistive technology and even the discovery of genes linked to ALS.

Though Senerchia died in November 2017, his legacy lives on. Following up on the success of the Ice Bucket Challenge, the ALS Association launched the Challenge Me initiative in 2019. The hope? Putting an end to this deadly disease for good.

Medically reviewed in November 2018. Updated in September 2019.

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