Amyotrophic Lateral Sclerosis (ALS), also known as Lou Gehrig’s disease, is a progressive neurological disease of the nervous system that causes the destruction of motor neuron cells. The motor neuron cells, which are responsible for voluntary movements, work to deliver messages from the brain down to the spinal cord and, in turn, to different muscles in the body. As a result of the motor neuron cells diminishing, patients with ALS will notice progressive muscle weakness causing daily routine activities to become increasingly difficult and at times completely impossible.
The majority of people diagnosed with ALS are usually aged between 40 and 80 years and statistically it affects men more frequently than women. Nevertheless, ALS can also occur in people in their 20s and 30s.
The rate at which the progression of ALS occurs varies from person to person and not all people suffering from the condition will experience the same symptoms or the same sequences or patterns of progression. However, progressive weakening of the muscles is experienced universally in patients with Amyotrophic Lateral Sclerosis. Individuals with ALS have an average survival time of three to five years after diagnosis, with twenty percent living five years or more and around ten percent living for more than ten years. Although there is currently no cure for the disease, some patients have been able to slow down the progression of their condition with the help of various treatments.
The speed at which the symptoms of Amyotrophic Lateral Sclerosis worsen and become life threatening varies from person to person. In general, the progression of ALS is divided into three distinct stages, each with associated symptoms of different levels of severity.
Nevertheless, the onset of the disease could also differ depending on which muscles are initially affected. In the early stages of ALS, signs and symptoms may hardly be noticeable, but will gradually become more apparent over time.
Some of the most common symptoms include:
Some of the earliest symptoms many ALS patients have occur in the hands or arms (limb-onset), which are made up of as many as 30 individual muscles working together to achieve diverse movements. In this stage, the symptom is usually limited to a single part of the body. Patients will find themselves having difficulty performing simple tasks that require manual dexterity such as writing, grasping objects, holding objects, or buttoning a shirt. Overtime, however, as the muscles are left unused for an extensive period of time, as well as the natural progression of the disease, the muscles may cause contractures, leaving the joints rigid and sometimes deformed.
Difficulty walking is another early sign of limb-onset Amyotrophic Lateral Sclerosis, where some patients might experience these symptoms even before they are diagnosed with the disease. However, in the middle stage when the symptoms have become more widespread, with some paralysed and weakened muscles, patients will have difficulty standing on their own and are at risk of falling. If and when ALS patients fall, they may not be able to get back up on their own. In the late stage of ALS, patients will lose the ability to walk, as well as all voluntary movements in their legs.
Due to the damage of motor neurons, the onset of ALS may include symptoms such as fasciculations, or muscle twitches, cramps and/or spasticity, which is a condition in which certain muscles are continuously contracted, resulting in stiffness and tightness. These conditions could interfere with movements and gait. Spasticity, for instance, has a negative effect on muscles and joints and can cause deformities. In the later stage, patients with Lou Gehrig’s disease will experience muscle loss and/or atrophy, and ultimately, paralysis.
According to the ALS Association, muscle weakness is the initial symptom in 60 percent of the people with the disease. Muscles twitch, become stiff and cramp, and ultimately waste away. In most cases usually within 3 to 5 years, the weakness spreads until all of the limbs are paralysed.
Muscle twitches, also known as fasciculations, are a predominant feature of motor onset ALS and are characterised by random jerky muscle movements. These occur due to muscle weakness and impaired nerve supply to the muscles.
Difficulty speaking and swallowing are caused by the weakening and paralysis of the vocal cord. The two symptoms indicate a clinical marker of Bulbar-onset ALS. Although they can occur during any point in the progression of the disease, most ALS patients develop these bulbar affected symptoms at the later stage, following more common Limb-Onset symptoms.
Trouble in swallowing, which occurs gradually in some patients and suddenly in others, puts these patients in the risk of choking. Not only that, an inability to swallow makes eating and drinking impossible, resulting in dramatic weight loss in the case of many ALS patients. On the other hand, difficulty speaking manifests signs of speech declination and reduction in speech intelligibility and rate. Speech may be soft, thick-sounding or slurred.
As a result of gradual muscle deterioration, ALS patients’ neck extensor weakens, and slowly becomes dysfunctional. This symptom can be seen as an early feature in the onset stage, whilst the others develop it during the later stage.
Over time, Amyotrophic Lateral Sclerosis results in trouble with breathing due to paralysis of the lung muscles used to inhale and exhale as well as the diaphragm. Patients can also experience shortness of breath, fatigue, disturbed sleep, and/or morning headaches. Eventually, one may need a device to help in breathing at night to provide continuous positive airway pressure (CPAP) or bi-level positive airway pressure (BiPAP) or an artificial ventilator. It worsens over time and is generally the cause of death. In a rare case is breathing the first symptom of ALS, which implies the severity of the disease. Respiratory failure remains the most common cause for death of ALS patients.
According to the National Institute of Health, ALS patients are at high risk of getting food, liquid or saliva into the lungs while trying to swallow, causing pneumonia. This occurs since the secretions accumulate in the lungs as the lungs are too weak to clear them effectively. Inhaling food or fluids results in pneumonia. In order to reduce these risks and ensure proper nutrition and hydration, artificial feeding through a feeding tube or intravenous solution is the only solution for ALS patients.
Patients in the later stages of ALS become totally paralysed as a result of muscles atrophy. Due to mixed signals from the brain and the spinal cord, muscle twitching often occurs without any purposeful movement. At the end stage, ALS patients become totally dependent on others for care.
Since ALS is a devastating disease and patients continuously lose their functions, it often comes with a depressive mental state.
Since this neurodegenerative disease attacks only motor neurons, sense of sight, touch, hearing, taste and smell do not get affected and for many people, the muscles of the eyes and bladder usually remain unaffected. Since ALS does not usually affect cognitive ability, patients are able to remain actively involved with their circle of friends and family. Moreover, ALS does not directly impact sexual function or cause pain but inability to move and other conditions may have their indirect impact. Hearing, vision and touch usually remain normal. Thus, ALS affects every patient differently depending on the severity and the location of the signs and symptoms. Doctors have been able to identify and diagnose ALS patients through some tests and trends.