If you’re having trouble walking or notice muscle weakness, you might be wondering, could it be multiple sclerosis (MS) or amyotrophic lateral sclerosis (ALS)? While these conditions have similar-sounding names and can affect how you move, they are very different diseases.

In this article, we will explore the key differences between ALS and MS to help you better understand these conditions.

1. ALS and MS Affect the Body in Different Ways

ALS and MS damage different parts of your nervous system. In ALS (also called Lou Gehrig’s disease), the nerve cells that control your muscles break down over time. This leads to muscle weakness and makes it harder to move. The ALS Association explains that as these nerves degenerate (deteriorate), sclerosis (scarring) happens in your spine.

MS works differently. It’s an autoimmune disease, which means your immune system attacks your own body. Specifically, it damages the myelin sheath (protective coating) around your nerve fibers, causing sclerosis in your brain and spinal cord.

2. ALS and MS Are Likely To Affect Different Groups of People

There are varying profiles of people who are diagnosed with ALS or MS, and there are some patterns for each.

For ALS:

• Men are 20 percent more likely to develop ALS than women before age 65, according to the ALS Association. As they age, women become as likely as men to receive the diagnosis.
• Most people are diagnosed around age 55.
• White people make up about 75 percent of ALS cases in the U.S., according to a 2014 study published in the journal Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration.
• Military veterans are at a higher risk of developing ALS, possibly due to head trauma, extreme physical exertion, or exposure to lead, toxic chemicals, or pesticides.

For MS:

• Roughly 1 million people in the United States have multiple sclerosis.
• Women are three times more likely than men to have relapsing-remitting MS, according to the Multiple Sclerosis Association of America. The gender split is about even for those who have primary progressive MS.
• Most people with MS are usually diagnosed between the ages of 20 and 50.
• Caucasians with Scandinavian or northern European ancestry are more likely to get MS, though it is possible for anyone to get it regardless of their background, according to the Multiple Sclerosis Association of America.

Keep in mind that having some or all of these characteristics does not mean that you will definitely get MS or ALS. However, if you fall within one of these categories, it may help doctors pinpoint the cause of your symptoms and create a treatment plan faster.

3. ALS and MS Have Different Risk Factors

While the exact cause of both ALS and MS is unknown, researchers have found some important genetic clues.

Between 5 percent and 10 percent of ALS cases are “familial ALS” and are inherited through a gene mutation (change). Children of people with familial ALS have a 50 percent chance of developing it. By contrast, having a first-degree relative (parent or sibling) with MS only raises your risk by 3 percent to 4 percent. You might be at an increased risk if you have low vitamin D levels, which can happen if you live further from the equator, where there is less sunlight.

The risk of both diseases might be impacted by environmental factors. Smoking could be a risk factor for both ALS and MS. Women who smoke are 1.6 times more likely to develop MS compared to women who don’t smoke, according to the Multiple Sclerosis Association of America. Additionally, exposure to toxic chemicals might be a risk factor of ALS, and recent studies have shown that Epstein-Barr Virus may also play a role in MS.

4. ALS and MS Have Different Early Symptoms

While ALS and MS can share some symptoms, their early warning signs are often different. Generally, walking difficulty, weakness, muscle spasms, dropping things, tripping, and trouble chewing, swallowing, and speaking can all be symptoms of both ALS and MS.

People with ALS lose the ability to control their muscles as nerve cells in the brain and spinal cord progressively degenerate. While not all people who have ALS report the same symptoms or rate of progression, early symptoms of ALS signs include:

• Difficulty speaking clearly or garbled speech
• A tendency to drop things
• A pattern of tripping while walking
• Muscle weakness in hands, arms, or legs
• Involuntary laughing, crying, or yawning
• Problems with chewing and swallowing

Early symptoms of MS also vary widely, but some common symptoms can include:

• Dizziness
• Vision problems
• Numbness or tingling feelings
• Problems with balance
• Muscle weakness
• Brain fog or confusion

5. ALS and MS Are Diagnosed Differently

Many of the symptoms of both MS and ALS mimic other conditions, so your doctor will need to begin the diagnostic process with a neurological exam. They will also ask you about your family history and your work history, and about potential environmental exposures you may have had.

ALS can be hard to diagnose since there isn’t a definitive test. Oftentimes, if your neurologist suspects ALS, comprehensive testing may include:

• Magnetic resonance imaging (MRI) or X-rays
• Nerve, muscle, or motor neuron testing such as an electromyography (EMG) or nerve conduction velocity (NCV)
• Blood and urine tests
• Nerve or muscle biopsies

Because there is no definitive test for the disease, the ALS Association recommends getting a second opinion from a certified ALS specialist.

After reviewing medical history and completing a neurological exam for MS, your doctor may also perform diagnostic testing such as:

• Brain and spine MRI
• Spinal fluid testing, also known as a cerebrospinal fluid analysis (CSF) or spinal tap
• Blood tests to eliminate other conditions with similar symptoms

ALS and MS are two distinctly different diseases, but there are very rare cases when a dual diagnosis of both MS and ALS have been made.

6. ALS and MS Have Different Treatment Options

Neither ALS nor MS has a cure yet, but doctors have different ways to help people with each condition. To treat ALS, your doctor may recommend:

• Medications to help with symptoms like muscle cramping and pain
• Physical therapy or occupational therapy to maintain movement
• Speech therapy to help with communication
• Breathing support when needed
• Nutritional care

For MS, a treatment plan may include:

• Injectable, oral, or infusion disease-modifying therapies (DMTs) to slow down the disease
• Treatments for specific symptoms like muscle stiffness or fatigue
• Physical therapy
• Medications to improve quality of life

7. ALS and MS Have Different Disease Progressions and Life Expectancies

ALS and MS affect people’s lives very differently. For ALS, conditions tend to continuously get worse over time. ALS is a fatal disease. The average life expectancy is two to five years after diagnosis, but according to the ALS Association, some people can live five to 10 years or longer after diagnosis. As ALS progresses, the muscles used for walking, swallowing, chewing, talking, and breathing become affected. Feeding assistance and ventilators are required in the late stages of the disease, with the onset of paralysis.

Many people with MS live nearly as long as those without MS, and they can experience periods with no symptoms between flare-ups. Even when researchers account for severe cases of MS, they have found the disease to reduce the average life expectancy by six or seven years.

The Relationship Between ALS and MS

People often ask if MS can turn into ALS or if they’re related, but remember that ALS and MS are separate diseases. Having one condition doesn’t mean you’ll get the other, as they affect different parts of the nervous system. It’s relatively rare for someone to have both conditions.

Living with either condition can be challenging, but you’re not alone. Regularly communicating with your doctor and staying connected with others who understand your experience can allow you to share advice and stories. It can also help you stay up to date with new treatments, clinical trials, and research currently taking place.

Find Your Team

MyMSTeam is the social network for people with MS and their loved ones. On MyMSTeam, more than 218,000 members come together to ask questions, give advice, and share their stories with others who understand life with MS.

Have you been through the diagnostic process for ALS or MS? What advice do you have for others going through diagnostic tests? Share your experience in the comments below, or start a conversation by posting on your Activities page.