Amyotrophic lateral sclerosis

Each one of you might have heard about famous theoretical physicist, cosmologist and author, Stephen Hawking. Do you know about the disease from which he was suffering? Do you remember the Ice Bucket Challenge for raising awareness of this disease? If not, then don’t worry, as we are going to discuss it. So, the disease was Amyotrophic lateral sclerosis or ALS. Amyotrophic lateral sclerosis (ALS) is often called Lou Gehrig’s disease which was named after the famous baseball player who was diagnosed with it.

WHAT IS ALS?

A-myo-trophic comes from the Greek language.

  • A” means No
  • Myo” refers to Muscle
  • Trophic” means Nourishment – “No muscle nourishment

As the muscle has no nutrition it atrophies.

Amyotrophic lateral sclerosis or ALS  is one of the several types of motor neuron disease. It is a group of rare neurological diseases. It is a progressive nervous system disease that is, the symptoms get worse over time, which affects nerve cells of the brain and spinal cord, subsequently losing muscle control. It gradually and inevitably paralyzes patients and usually kills them within four years. Most people with ALS die from mainly respiratory failure, usually after 3 to 5 years of the appearance of symptoms.  Although, 10 per cent of the affected people from ALS have survived 10 years or more. It often starts as mere muscle twitching (fasciculations) or maybe weakness in the limb or Dysarthria (slurred speech).

TYPES OF AMYOTROPHIC LATERAL SCLEROSIS

There are mainly two kinds of ALS

  1. SPORADIC ALS is the most common type of ALS. It affects up to 90 to 95% of the cases. There is no clear cause or risk factor for this type.
  2. FAMILIAL ALS (FALS) is hereditary. About 5 to 10 per cent of people affected are suffering from this kind of ALS. FALS is caused by a change in the sequence of genes.

SYMPTOMS OF AMYOTROPHIC LATERAL SCLEROSIS

Early symptoms of ALS include muscle stiffness or weakness. These signs and symptoms may vary from person to person, depending on the neuron affected. Not all people suffering from ALS experience the same symptom or same patterns of progression. ALS does not affect your mental abilities. Though, progressive muscle weakness and paralysis are universally experienced. Signs and symptoms include the following:

  • Trouble in doing normal daily activities or even walking
  • Loss of balance
  • Fasciculations or twitches in the arm, leg, shoulder or tongue, clumsiness
  • Slurred and nasal speech or trouble swallowing
  • Untimely laughing, crying or yawning
  • Cognitive and behavioural changes
  • Shortness of breath or trouble breathing

CAUSES OF AMYOTROPHIC LATERAL SCLEROSIS

The cause of ALS is not known yet; researchers are still searching for why ALS occurs in some people and not in others. The evidence from scientific studies shows that both genetics and environment play some role in the development of ALS. The other possible causes are glutamate, immune system problems, mitochondria problems, or oxidative stress.

GENETICS

ALS is inherited in 5 to 10 per cent of people, as found in a study (familial ALS). In people with familial ALS, their little ones have a 50 per cent probability of developing this disease. Some studies examined the entire human genome and found many similarities between the genomes of people with familial ALS with some people having non-inherited ALS. Genetic variation like these might make people more vulnerable to ALS.

ENVIRONMENTAL FACTORS

On the lookout for the cause of ALS, researchers started studying the impact of environmental factors on ALS. Researchers are investigating many areas that could be responsible like exposure to toxic agents, viruses, diet, behavioral and occupational factors. Environmental factors which trigger ALS are as follows:

  • SMOKING– Cigarette smoking is very likely to be the risk factor triggering ALS. The risk factor is higher for women after menopause.
  • MILITARY SERVICES– Studies suggest that people who have served in the military are at higher risk of suffering from ALS. The reason behind this is still not clear. It may be due to exposure to certain chemicals or metals, injuries, or intense exertion. Researchers have suggested that it may be due to exposure to toxins during warfare and strenuous physical workout may be the reason why some veterans and athletes are at higher risk.
  • TOXIN EXPOSURE– Some cases suggest that exposure to toxin might have induced the development of ALS. Many studies have been conducted but no single agent has been found uniformly associated with this disease. Dietary factors like neurotoxin present in the seed of tropical cycad plants, Cycas circinalis, is believed to be the reason behind increasing cases of ALS in the West Pacific Guam region.

DIAGNOSIS OF AMYOTROPHIC LATERAL SCLEROSIS

No test can provide a definite diagnosis for ALS. However, the presence of lower and upper motor neuron symptoms in a single limb is quite intriguing. The diagnosis is primarily based on the symptom and other series of tests are run to rule out other diseases like ‘ALS- mimics’. Numerous biomarkers are being studied for diagnosis. The diagnosis includes a series of steps like MRI ( Magnetic Resonance Imaging) of the neck and sometimes head and lower spine, EMG ( electromyography) which generally tests nerve conduction, and series of blood tests. Sometimes genetic tests, urine tests, or a lumbar puncture (also known as a spinal tap) are also sometimes necessary.

PREVALENCE:

  • The frequency of ALS is 6 per 1,00,000 of the total population.
  • The occurrence of ALS is higher in cases of people aged above 50 years.
  • The male to female ratio occurrence of this disease is 2:1. Incidence peaks at about the age of 55 to 65 years.
  • According to a report of the Foundation for Research on Rare Diseases and Disorders, the prevalence of ALS cases in India is 5 in 1,00,000.

TREATMENT:

As of now, there is no treatment for ALS but management focuses on treating signs and symptoms and providing better supportive care for leading a better life.

It mostly depends on the stage of the disease. Medication and therapy can decrease the rate of progression and minimise discomfort.

  • Physical therapy
  • Palliative care
  • Drugs like muscle relaxants and glutamate blocker
  • Gastrostomy and Tracheostomy

RECENT ADVANCES AND FUTURE APPROACH:

There are mainly three categories where research is being done – gene therapy, stem cells and drugs. Cellular and molecular studies seek to understand the mechanisms which trigger these motor neurons to degenerate. Many researches are ongoing by different institutions. RNA- based drug discovery for treatment of ALS is going on by Cerevance Inc. Another study is LBT-3627: A Novel Immunomodulatory Disease-Modifying Approach to ALS Treatment. These are just a few listed here.

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REFERENCES-

  1. https://www.als.org/understanding-als/what-is-als
  2. https://www.massgeneral.org/neurology/als/patient-education/diagnosing-als
  3. http://www.rarediseasesindia.org/als
  4. https://www.webmd.com/brain/understanding-als-basics
  5. https://stanfordhealthcare.org/medical-conditions/brain-and-nerves/amyotrophic-lateral-sclerosis/types.html

3 Comments

  1. Supriya shukla

    Very crucial knowledge..as always

  2. Nandan Kumar

    Helpful

  3. Gilgamesh

    Just what I wanted

Comments are closed