“A 40-year-old person from Dubai came to our hospital with foot drop [difficulty in lifting the foot due to muscle weakness] only on the right side while walking. Also, the person said there were no other significant symptoms besides occasional muscle twitching (fasciculations) in the upper limbs,” recollects Dr A Nalini, professor, department of neurology, National Institute of Mental Health and Neurosciences (NIMHANS), Bengaluru.
Despite the absence of prominent symptoms, Dr Nalini and her team suspected a more severe underlying condition. Consequently, they conducted a comprehensive medical evaluation to ascertain the true nature of the person’s ailment. The meticulous evaluation revealed the presence of fine muscle twitches in the tongue, which had been overlooked in an earlier examination elsewhere.
The final diagnosis delivered unsettling news to the person: amyotrophic lateral sclerosis (ALS).
Amyotrophic lateral sclerosis is a progressive neuromuscular health condition characterised by the degeneration of motor neurons responsible for the movement of muscles in the body. First described and named by the French neurologist Jean-Martin Charcot in the 19th century, ALS is often called Charcot’s disease. The term ‘amyotrophic’ signifies muscular atrophy or loss of muscle, while ‘lateral sclerosis’ refers to the scarring or hardening of tissues in the lateral spinal cord. The typical symptoms of amyotrophic lateral sclerosis are muscle weakness, atrophy and fasciculations.
Dr Nalini says the survival rate is low for amyotrophic lateral sclerosis – typically 3-5 years after its onset. However, in the Indian population, it is slightly higher, spanning between 7-9 years or sometimes up to 15 years after onset, she adds. She also states that ALS affects men more than women, with a ratio of 1.5:1 globally. However, for Indians, this ratio is about 3:1, and the mean onset age is between 55-65 years.
Muscles in peril
The onset of symptoms is usually limited to one region of the body, which progressively spreads to adjacent body regions, says Dr Nalini. She enlists the hallmark symptoms of ALS:
- Progressive muscle weakness accompanied by loss of muscle (muscle atrophy),
- muscle twitching (fasciculations),
- muscle cramps and slowness of movements with muscle stiffness,
- Weakness and atrophy in upper or lower limb muscles or in bulbar muscles that helps in speech, chewing and swallowing. Weakness of bulbar muscles leads to difficulty in speech (dysarthria), swallowing (dysphagia), and drooling.
- Head drop and posture issues are common in later stages. About one‐third of the affected can have bouts of uncontrolled laughing or crying, referred to as a pseudobulbar effect.
Dr Nalini adds that, individuals with amyotrophic lateral sclerosis experience an elevated basal metabolic rate, often resulting in weight loss despite receiving sufficient nutrition. In addition to the physical manifestations, cognitive functions are also affected, leading to memory loss or dementia. The rapid progression of the disease ultimately culminates in complete paralysis.
Dr Rajani Bhat, pulmonologist, Sparsh Hospital, Bengaluru, says, “The muscle involved in breathing becomes weak over the period, and the person has breathlessness and eventually respiratory failure in a few years.”
Read more: Silent Struggles: the effect of amyotrophic lateral sclerosis on speech and swallowing
Read more: Fading signals: detecting the symptoms of amyotrophic lateral sclerosis
Unravelling the culprits
A complex interplay of cellular processes leads to this form of neurodegeneration. “The exact cause for the development of amyotrophic lateral sclerosis is unknown. Although several mechanisms have been proposed, mutations in certain genes, glutamate excitotoxicity, viral infections, inflammation and changes in gut microbes lead to degeneration of motor neurons and ultimately amyotrophic lateral sclerosis,” says Dr Nalini.
Around 10 per cent of amyotrophic lateral sclerosis cases are familial, with at least one family member affected. The remaining 90 per cent are sporadic and is caused by multiple factors. Motor neurons in the spinal cord and specific brain regions such as the cerebral cortex and medulla oblongata are affected in amyotrophic lateral sclerosis. Upper motor neurons and lower motor neurons are degenerated.
Read more: Behind the agony of amyotrophic lateral sclerosis
Diagnosis
Diagnosing amyotrophic lateral sclerosis (ALS) is a complex process, as there is no definitive test for its identification. Instead, a combination of medical history review, physical examination, neurological testing, and imaging studies are used to evaluate and detect the presence of the disease. Some of the diagnostic examinations used are:
- Needle Electromyography detects the electrical activity of muscle fibres and can help to diagnose ALS.
- Nerve conduction study is also performed to diagnose ALS in which the nerve’s ability to send a signal to the muscle is assessed.
- Magnetic resonance imaging gives detailed brain and spinal cord images and provides insights into neurodegeneration in certain regions.
- Ultrasound of muscles can be done to look for twitching in muscles.
- Genetic testing plays a crucial role, particularly in inherited ALS. Mutations in specific genes associated with ALS, such as C9orf72, SOD1, TDP‐43, FUS, and TBK‐1, are examined to determine their presence and contribution to the disease.
Navigating solutions
Dr Nalini emphasises that due to the complexity of this health condition, a cure for amyotrophic lateral sclerosis remains elusive. However, pharmacological and non-pharmacological approaches provide some relief for the symptoms.
Slowing with medicines:
Medicines are often prescribed to slow the disease progression. They target the glutamate receptors in the neurons. Other medications help manage symptoms, including muscle cramps, stiffness, excess saliva, unwanted crying and/or laughing, or other emotional displays.
Lifestyle and supportive therapies:
- Dietary changes: Modifying the consistency of the diet, controlling the size of each swallow, and implementing a high-protein, high-calorie diet can help improve nutrition and manage ALS-related challenges.
- Nutrition via feeding tube: When caloric intake becomes insufficient, or swallowing becomes impossible, the option of nutrition via a feeding tube can be considered to ensure proper nourishment.
- Speech therapy: As communication abilities are impaired in ALS, speech therapy plays a vital role. In cases where speech is lost, speech-generating devices can facilitate effective communication.
- Non‐invasive ventilation (NIV): It is recommended when there is respiratory insufficiency. It involves breathing support delivered through a mask placed over the nose or mouth.
These measures only help manage the symptoms and not reverse the course of ALS. The individual can lead a better quality of life. Collaborating with healthcare professionals can help tailor these interventions to meet the specific needs of the affected individuals.
