What Is Amyotrophic Lateral Sclerosis?

One of the famous baseball players, Lou Gehrig ended his glorious streak in ‘39 soon after he was diagnosed with amyotrophic lateral sclerosis. Since then, the disease came to be known as Lou Gehrig’s disease. Though the symptoms were known, people were completely unaware of the disease until the 19th century. It was Jean-Martin Charcot, a French neurologist, who termed this motor neurone disease as amyotrophic lateral sclerosis.¹

ALS, also known as amyotrophic lateral sclerosis, is an uncommon condition characterised by the progressive damage of neurones, leading to a loss of motor function. These motor neurones serve as the channel for voluntary movements, branching out from the brain to the spinal cord and to the individual muscles. As these neurones degenerate, patients gradually experience a reduction in their ability to walk, speak, eat and even breathe.

Since its discovery, there have been medical advancements and cultural transformations. The “ice bucket challenge” was one of the phenomena which garnered immense support and gathered around $200 million funds to the ALS association. Below, you can find further information.

Overview

Amyotrophic lateral sclerosis is a fatal neurodegenerative disease with marked loss of muscle function. Amyotrophic lateral sclerosis is a Greek term where “A” means no, “myo” means muscle, and “trophic” means nourishment. So, the word “amyotrophic” means no nourishment to the muscle. “Lateral” means the affected spinal area of the nerve cells that control the muscles. “Sclerosis” means hardening or scaling.²

If there is no proper nourishment to certain areas of the spinal nerves that control the muscles, they waste away. So, people suffering from ALS experience nerve cell loss where neurones do not receive proper nourishment and stimulation, resulting in wasting of the muscle and loss of muscle movement, with eventual paralysis and ultimately death due to respiratory failure.

In most of the cases, motor neurones are affected (muscle weakness of limbs or muscular atrophy) whereas, in some, people may experience damage to the bone (Paget's disease of the bone) and muscle (inclusion-body myositis). In 25-30% of cases, people may experience difficulty in speech (dysarthria) and swallowing (dysphagia).³

ALS exhibits enormous changes to our systems like behavioural changes, motor problems and/or dementia within a short span of time. It is a progressive disease, where the patient tends to get worse and symptoms start accumulating. Symptoms are mild to severe and once they start appearing, death usually occurs in 2-4 years.⁴

It affects people of all races, ethnic backgrounds, ages and gender. People assigned male at birth (AMAB) are slightly more likely to be affected but the gender difference disappears as people age. All ages are prone to be affected by ALS, but the symptoms start to appear at ages 60-70 years. There are no treatments to stop or reverse the condition and there is still much to learn about what causes ALS.⁵

Causes of amyotrophic lateral sclerosis

The real cause⁶ of ALS is unknown just like other neurodegenerative diseases, but it is thought to be caused by a combination of various risk factors like environmental factors, age and also by any close relative or a family member who has the hereditary form of the disease.

Familial ALS: Of all people suffering from ALS, only 10 per cent are known to have familial ALS in which a mutated gene is inherited and is passed on to the next generation. There are four types of genes responsible for ALS: SOD1, C9orf72, TARDBP and FUS genes. If there is a mutation seen in any of these genes, it produces a protein that is toxic in nature. Accumulation of this toxin in the body results in the loss of voluntary control of the muscles, leading to involuntary control of the organ systems.

Sporadic ALS: Nearly all cases are said to be sporadic, where the cause of the disease is unknown without any associated risk factors or with no family history involved. They occur spontaneously and without a clear pattern. Various possible causes that are still under investigation include an abnormal immune system, glutamate toxicity, and oxidative stress.

Environmental ALS: Several studies suggest that occupational and environmental exposures to metals, pesticides, head injuries and viral infections and other risk factors such as smoking and physical exercise may play a role in ALS. Studies also suggest that military veterans are two times more likely to be affected, with a possible reason being an exposure to lead or other environmental toxins, but the exact reason for it is still unclear.

Signs and symptoms of amyotrophic lateral sclerosis^3-7

ALS early onset usually starts with weakness in limbs (spinal onset), showing loss of muscle strength, resulting in muscle cramps or twitching in muscles also called limb-onset ALS, or trouble swallowing or speaking (bulbar-onset) called progressive bulbar palsy.

Spinal onset presents with weight loss, spasticity (muscle tightness), muscle twitches, muscle cramps or weakness in the arms, legs or feet, tripping or falling, trouble walking or doing any daily activities that involve the movement of hands and feet.

People with bulbar-onset often show symptoms of trouble speaking, chewing, swallowing, or episodes of uncontrollable laughing or crying. As the disease worsens, it spreads to other muscles causing difficulty in breathing, which is the end stage of the disease where the patient requires ventilation to survive.

Cognitive symptoms like memory loss, getting easily distracted, acting inappropriately or impulsively, lack of planning or organising, and lack of insight in social situations are common, whereby ALS is often overlapped with another neurological disorder called frontotemporal dementia.¹

Management and treatment for amyotrophic lateral sclerosis^3-7

ALS cannot be cured, but there have been advances in therapy to improve the life of the patient. Treatment differs from person to person. Healthcare specialists and neurologists are working together to take care of patients by relieving their symptoms and also helping them to maintain a good quality of life. There are no single tests for diagnosing the disease and it is difficult to test at early stages as most neurological disorders have similar symptoms. Brain and spine scans help rule out other conditions, and there are also spinal taps (where the fluid from the spine is tested), genetic testing (where the genes responsible for ALS are tested), as well as tests that identify muscle function.

Accepting the diagnosis and living with the disease can be very difficult as ALS is a multi-system disease. Various therapies are used to manage the symptoms, and physical, emotional and nutritional needs are taken care of by palliative care teams.⁸

• Occupational therapy, involving a specialist nurse, is suggested to help make everyday tasks easier.
• Physiotherapy is most commonly advised by the healthcare specialist for muscle strength training, to relieve muscle pain and overall physical fitness. 
• Patients may need support from a nutritionist for suggestions about the foods to be taken for easy swallowing and chewing. 
• A speech therapist can teach you about the techniques to communicate. 
• A healthcare provider may test for regular breathing and suggest non-invasive ventilation.

Medication: Riluzole is prescribed for reducing glutamate toxicity as it slows down the disease and increases life expectancy. Edaravone increases the daily activities of an individual by preventing oxidative stress.⁹ Drugs like baclofen (Lioresal) or tizanidine (Zanaflex), are used to relieve muscle spasms. Antidepressants, antioxidants, and vitamin supplements are also recommended based on the patient’s condition. 

FAQs

How is amyotrophic lateral sclerosis diagnosed?

It is difficult to test ALS, as its symptoms are common and similar to any other neurological disorder. Scans of the brain and spine may be helpful in ruling out disorders, and a spinal tap may be used, where the fluid of the spine is tested for any abnormalities. Genetic testing is done to check if the individual carries a faulty gene that is responsible for ALS.^10,11,12 There are also tests to identify muscle strength and blood.⁷ 

Can I prevent amyotrophic lateral sclerosis?

ALS is a complex disease with no definitive preventive measures.¹³ Leading a healthy lifestyle, preventing exposures to heavy metals, and engaging in activities to keep your brain healthy may all play a role in slowing down the progression of the disease. As the disease differs from person to person, patients are consulted for personalised advice.

Who is at risk of amyotrophic lateral sclerosis?

As the real cause of the disease is still not known, a person’s background, race, age, family history, and environmental risk factors (exposure to heavy chemicals/metals etc.), may put them at a higher risk of ALS. People AMAB are slightly more affected than people assigned female at birth (AFAB), but the gender difference disappears with age.¹⁴

How common is amyotrophic lateral sclerosis?

ALS is present worldwide. Every year, out of 100,000 people, 3-4 new cases are diagnosed with ALS in the U.S. The annual incidence of ALS is approximately 2 to 3 cases for every 100,000 people, and it is suggested that around 1,500 to 2,500 new cases of ALS are diagnosed in the UK each year.

When should I see a doctor?

You may want to see a GP if your close relative is suffering from the disease and you are worried that you may be at risk too. You should see a GP if early symptoms like muscle weakness pop up. The symptoms are unlikely to be ALS, but correct diagnosis in the early stages helps you get the care and support needed.

Summary

In ALS, motor neurones that are responsible for the voluntary movements of limbs are affected. As a result, the brain loses its ability to control the muscles that initiate movement, leading to muscle weakness and eventual paralysis. Common symptoms include difficulty in swallowing, speaking, muscle twitches or mobility issues. With age, the disease progresses, affecting cognitive function, and there is no proper cure for the condition. Many supportive care approaches are considered that can help manage symptoms and improve a patient's daily life.