Diseases and Disorders

Amyotrophic Lateral Sclerosis: An Overview

Anaya Aswale


Introduction

Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s Disease, is a progressive neurodegenerative disease that affects nerve cells in the brain and spinal cord [1]. According to the ALS Association, more than 5,600 people are diagnosed per year and as many as 30,000 Americans currently are affected [2]. Out of those 30,000 Americans, 60% are found to be males and 93% are Caucasian [3].  This article will look into the causes, methods of diagnosis, symptoms, and treatments for Amyotrophic Lateral Sclerosis.

 

Causes and Risk Factors

ALS is a neuromuscular disease that is characterized by progressive weakness in the muscles, which can eventually lead to paralysis, as a result of the death of motor neurons located throughout the nervous system. The death of motor neurons leads to muscle weakness. Though the cause of Amyotrophic Lateral Sclerosis is not known, scientific evidence from studies suggests that genetic and environmental factors may have an effect on the development of ALS [4]. 

Figure 1. An infographic that presents an overview of all the causes and risk factors [6].

In 1993, scientists found that mutations in the superoxide dismutase 1 (SOD1) gene were linked to some cases of ALS found in families. In fact the discovery of certain mutations has led scientists to believe that changes in the processing of RNA may cause motor neuron degeneration, since RNA is an important molecule in synthesizing specific proteins and performing activities relating to gene regulation [4]. Researchers are in the process of studying the chemical imbalances in people with ALS; specifically, glutamate, a chemical messenger in the brain which is known to be toxic to nerve cells at elevated levels [5]. Researchers are also studying the impact of environmental factors, such as viruses, diets, and more. They have suggested that exposure to certain toxins during war or demanding physical activities may be the reason why veterans and athletes have a higher chance of developing ALS [4].

Data shows that ALS is inherited in 5 to 10% of people, but for the rest of the population, the cause is unknown. However, when it comes to factors that may cause ALS, there is a suspicion that heredity, age, sex, and genetics could be risk factors.  In addition, smoking, toxin exposure, and military service have also been linked as factors that may trigger ALS [5].

 

Diagnosis

ALS is different for every person and therefore there is no one way to diagnose it. However, it is primarily diagnosed based on symptoms recognized by the physician. Since the symptoms are similar to that of Parkinson’s disease and stroke, it can be very difficult to diagnose. It may take several months to know for sure if someone has ALS since the disease gets worse over time and can inhibit eating, swallowing, and even breathing. Though diagnosis can be difficult, there are a few tests that are done to rule out other diseases. One test would be electromyography( EMG), which detects and records the electrical signals that are produced by muscle tissues as they contract. This test sends electric shocks through nerves in order to see if they are damaged. In addition, EMG will show if there is a clear abnormality in the muscles. Some other tests include Nerve Conduction Study (NCS), which measures a nerve's ability to send a signal to the muscles; X-rays, Magnetic resonance imaging (MRI), spinal tap, and blood and urine evaluations [4][7].

 

Symptoms

Though initial symptoms vary for different people, there are a few generic symptoms that may cause a doctor to suspect ALS. These symptoms include muscle twitching in the arms, leg, shoulder, or tongue, muscle cramps, tight and stiff muscles, muscle weakness affecting an arm, a leg, neck, or diaphragm, slurred and nasal speech, and difficulty chewing or swallowing [4]. The symptoms can begin either in the arms and legs or in speech and swallowing [8]. Despite where the symptoms begin, muscle weakness spreads to other parts of the body as the disease advances, eventually the disease will progress to a point where the diagnosed person will no longer be able to stand or walk, get in or out of bed on their own, or use their hands and arms [4].

Figure 2. A diagram of all the symptoms that are associated with ALS [9].

 

Treatments

Though there is no definite cure for ALS, treatments are available through therapy and medication. Medicines can control muscle cramping, difficulty swallowing, pseudobulbar affect (uncontrollable crying or laughing), pain, depression, and any other symptoms that arise as a result of ALS [7][4]. Often, doctors may prescribe Food and Drug Association (FDA) approved drugs like Riluzole and Edaravone to treat ALS. Riluzole is used to reduce damage to motor neurons by decreasing levels of glutamate and has shown to prolong survival by a few months [4]. According to the National Institute of Neurological Disorders and Stroke, “edaravone is believed to slow the decline of clinical assessments of daily functioning in persons with ALS” [4]. In addition, people affected by ALS may benefit from physical therapy. It can enhance a person’s ability to perform gentle and low-impact aerobic exercises and can improve cardiovascular health as well as help them cope with breathing problems, fatigue, and depression. Speech therapy, which can help a person maintain the ability to communicate, can also be beneficial for people with ALS [4].

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References

[1] “What Is ALS?”. ALS Association.http://www.alsa.org/about-als/what-is-als.html. Retrieved: 05/04/2019.

[2] “Quick Facts About ALS & The ALS Association”. ALS Association.http://www.alsa.org/news/media/quick-facts.html. Retrieved: 05/04/2019.

[3] “Understanding ALS”. ALS Association Texas Chapter.https://www.alstexas.org/understanding-als/. Retrieved: 05/04/2019

[4] “Amyotrophic Lateral Sclerosis (ALS) Fact Sheet”. National Institute of Neurological Disorders and Stroke, National Institute of Health.https://www.ninds.nih.gov/Disorders/Patient-Caregiver-Education/Fact-Sheets/Amyotrophic-Lateral-Sclerosis-ALS-Fact-Sheet. Retrieved: 05/04/ 2019.

[5] “Amyotrophic Lateral Sclerosis (ALS)”. Mayo Clinic, Mayo Foundation for Medical Education and Research.https://www.mayoclinic.org/diseases-conditions/amyotrophic-lateral-sclerosis/symptoms-causes/syc-20354022?utm_source=Google&utm_medium=abstract&utm_content=Amyotrophic-lateral-sclerosis&utm_campaign=Knowledge-panel. Retrieved: 05/04/2019.

[6] “ALS Causes”. Alstreatment.com, Unique Access Medical.https://alstreatment.com/amyotrophic-lateral-sclerosis-causes/. Retrieved:05/04/2019.

[7] Dowshen, Steven. (November 2017) “Lou Gehrig’s Disease (ALS)”. KidsHealth, Nemours.https://kidshealth.org/en/kids/als.html. Retrieved: 05/04/2019

[8] “Symptoms and Diagnosis”. ALS Association.http://www.alsa.org/about-als/symptoms.html. Retrieved: 05/04/2019.

[9] “ALS Overview”. ALS Pathways, Mitsubishi Tanabe Pharma America.https://www.alspathways.com/als-overview/. Retrieved: 05/04/2019.



    Anaya Aswale

    Anaya Aswale


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