Biological aging inevitably occurs in all organisms and related to a progressive reduction in the reparability and regenerative capacity of tissues and organs. An increasing aging population poses significant health-associated challenges in our society. Aging serves as one of the most prevalent risk factors for neuro-degenerative diseases, such as amyotrophic lateral sclerosis.
ALS is an irreversibly lethal disease characterised with the degeneration of motor neurons in the brain and spinal cord. There are 2 to 5 incidences of ALS per 100,000 individuals every year worldwide. Most people develop ALS between the ages of 40 and 70, with the average age of 55 at the time of diagnosis. The mean survival time of ALS patients is 2-5 years, but the rate at which ALS progresses varies among them.
Causes of ALS
The exact cause of ALS remains unknown. However, genetic and environmental factors have been suggested to be equally important in triggering ALS.
ALS can be classified into two main groups by their root cause. Familial ALS contributes to 5-10% of all ALS cases and only requires one parent to carry the gene responsible for ALS. Sporadic ALS, on the other hand, have no clear etiology and pathogenesis yet. The age of onset of sporadic ALS patients is about 10 years later than those with familial ALS.
Established causes for ALS
Heredity – familial ALS contributes to 5-10% of all ALS cases Genetics – four major ALS-linked gene variations (SOD1, TDP-43, FUS, and C9orf72) Sex – more men than women develop ALS before the age of 65 Age – risk increases with age
Environmental risk factors
Smoking – greatest for women, particularly after menopause Military service – may due to exposure to certain metals or chemicals, traumatic injuries, viral infections and intense exertion Environmental toxin exposure – exposure to lead or other toxic substances may increase risk for ALS
Symptoms and Diagnosis
Signs and symptoms of ALS vary due to the difference in the affected regions of neurons. Despite this, patients usually experience painless progressive muscle weakness and paralysis.
It is difficult to diagnose ALS at early stage since it shares common symptoms with other neurological diseases. Diagnostic methods are usually performed to rule out other conditions. These include MRI, blood and urine tests, muscle biopsy, electromyogram and nerve conduction study.
Slurred and nasal speech
Difficulty chewing or swallowing
Difficulty performing simple tasks such as writing
Awkwardness when walking or running
Muscle cramping/twitching: single body region
Minor symptoms, e.g. fatigue and poor balance
More widespread symptoms: paralysed muscles
Weakness is swallowing and respiratory muscle
Most voluntary muscles are paralysed
Extremely limited mobility; fail to use mouth; poor respiration
Majority is due to respiratory failure that progress slowly
Other possible cause: malnutrition, pulmonary embolism, cardiac arrhythmias and pneumonia
Drugs for ALS patients
Riluzole (Rilutek) and Radicava (Edaravone) are the only FDA-approved medications that can be used to treat ALS. Unfortunately, the treatment can only slow down the progression of the disorder. It cannot reverse the damage seen in ALS and only some of the patients respond to the treatment.
Supportive cares for ALS patients
Low-impact aerobic exercise (such as walking, swimming and stationary cycling): strengthen unaffected muscles, improve cardiovascular health and help people fight fatigue and depression
Speech therapy: maintain the ability to communicate
Nutritional support: ensure enough nutrients are absorbed and avoid food that are difficult to swallow; may involve the use of suction device to remove excess saliva and prevent choking
Breathing support: non-invasive ventilation treatment for patients who have respiratory insufficiency; mechanical ventilator for those with late-stage ALS