Amyotrophic lateral sclerosis (ALS) is a progressive neurological disease that affects the nerve cells responsible for controlling voluntary muscle movement. Commonly known as Lou Gehrig’s disease, ALS attacks nerve cells in the brain and spinal cord, leading to muscle weakness and, eventually, loss of muscle control.
Stay with us as we explore the critical aspects of ALS disease, including its symptoms, diagnosis, and treatments.
What is ALS?
Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig’s disease, is a severe neurological condition. It primarily impacts motor neurons—nerve cells in the brain and spinal cord responsible for controlling voluntary muscle movements like walking and talking.
As ALS progresses, these motor neurons deteriorate and eventually die, ceasing communication with muscles. This breakdown leads to muscle weakness, visible muscle twitching, and a reduction in muscle size.
Over time, individuals with ALS will find it challenging to perform voluntary movements, including essential functions such as breathing. Characterized by its progressive nature, ALS’s symptoms worsen, significantly impacting a person’s ability to move, speak, eat, and even breathe, as the disease advances.
What are the Signs and Symptoms of ALS Disease
The initial symptoms of ALS disease can vary considerably from person to person, and they may be so minor that they are overlooked. However, common early symptoms include:
- Muscle twitches in the arm, leg, shoulder, or tongue
- Muscle cramps
- Tight and stiff muscles (spasticity)
- Muscle weakness affecting an arm, a leg, or the neck
- Slurred and nasal speech
- Difficulty chewing or swallowing
As the disease progresses, symptoms spread, leading to issues such as:
- Difficulty with chewing and swallowing, which may cause drooling
- Challenges in speaking clearly
- Breathing difficulties
- Unexpected emotional outbursts, like crying or laughing
- Constipation and trouble maintaining weight due to eating difficulties
In the later stages, individuals with ALS may lose the ability to walk, stand, use their arms and hands, or breathe independently. Despite these physical challenges, their ability to think, remember, and understand remains intact, making them aware of their declining physical abilities. This awareness can lead to anxiety and depression. A small percentage may also face difficulties with language or decision-making, and some develop a type of dementia called FTD-ALS.
Who is most likely to get ALS?
ALS can affect anyone, regardless of gender, race, or age. However, certain risk factors increase the likelihood of developing the disease.
In the United States, the Centers for Disease Control and Prevention (CDC) estimates that over 16,000 people have ALS, with around 5,000 new diagnoses annually. Worldwide, ALS affects approximately 2–5 people in every 100,000.
Key risk factors for developing ALS include:
- Gender: Before the age of 65, men are slightly more likely to be diagnosed with ALS than women. However, this gender difference evens out after age 70.
- Age: ALS most often shows up in people in their late 50s or early 60s, though it can occur at other ages as well.
- Race: While anyone can develop ALS, Caucasian, non-Hispanic individuals have a higher incidence rate.
Causes of ALS Disease
While a small group of individuals inherits ALS, the cause remains unknown in most cases. Current research primarily explores genetics and environmental factors as potential triggers for ALS.
1. Genetics
ALS can be inherited, and research has found that certain genetic mutations can increase the risk of developing the disease. The C9ORF72 gene is responsible for making a protein in nerve cells in the brain and spinal cord, and mutations in this gene have been found in 20-40% of familial ALS cases and a few sporadic cases. The SOD1 gene, which is key to the functioning of motor neurons and other cells, has also been linked to 12-20% of familial ALS cases.
Additionally, a 2021 study found that mutations in the SPTLC1 gene are linked to a rare form of genetic ALS that affects children as young as 4 years.
2. Environmental Factors
Some studies have suggested that certain environmental factors may also play a role in the development of ALS. For example, one study found that military personnel deployed in the Gulf region during the 1991 war were more likely to develop ALS than those deployed elsewhere. Additionally, research has found possible links between ALS and:
- Mechanical or electrical trauma
- Military service
- High levels of exercise
- Exposure to high quantities of agricultural chemicals
- Exposure to high levels of a variety of heavy metals
However, there is no conclusive evidence that any lifestyle changes can reduce the risk of developing ALS.
3. Other Possible Causes
While genetics plays a role in some cases of ALS, the cause of the disease is still unknown in the majority of cases. Research has explored several other possible causes, including:
- Disorganized immune response
- Chemical imbalance
- Mishandling of proteins
Diagnosis of ALS
Diagnosing ALS is challenging, as there is no single medical test for it. Instead, a comprehensive diagnostic workup is necessary to rule out other neurological diseases that may cause similar symptoms.
- Electrodiagnostic Tests: Electrodiagnostic tests, such as electomyography (EMG) and nerve conduction velocity (NCV), are essential in evaluating the areas affected by ALS. These tests assess the functioning of muscles and nerves, particularly in the bulbar region (head, neck, and brain), cervical region (arms and diaphragm), thoracic region (muscles of breathing), and lumbar region (legs).
- Blood and Urine Studies: Blood and urine studies are crucial in ruling out other conditions that may cause similar symptoms. These tests include high-resolution serum protein electrophoresis, thyroid and parathyroid hormone levels, and 24-hour urine collection for heavy metals.
- Spinal Tap: A spinal tap, also known as a lumbar puncture, is a procedure that involves collecting cerebrospinal fluid from the spine. This test helps to rule out other conditions that may affect the central nervous system.
- Imaging Tests: Imaging tests, such as X-rays and magnetic resonance imaging (MRI), are used to visualize the brain and spinal cord. These tests help to identify any structural abnormalities that may be contributing to the symptoms.
- CT Scan of the Cervical Spine: This is a specific imaging test for evaluating the neck and brain region.
- Muscle and Nerve Biopsy: In some cases, a muscle or nerve biopsy may be necessary to confirm the diagnosis of ALS. This involves removing a small sample of muscle or nerve tissue for examination under a microscope.
- Neurological Examination: A neurological examination is an essential part of the diagnostic workup for ALS. It evaluates the patient’s symptoms, medical history, and physical condition.
Treatment of ALS Disease
While there is currently no cure for ALS disease or a way to reverse the damage to motor neurons, there are treatments available that can slow the disease’s progression, improve life quality, and potentially extend survival. In recent years, new treatments have emerged, and ongoing research continues to explore different approaches to delay the progression of ALS.
Supportive care is essential for individuals with ALS, and it is best provided by integrated, multi-disciplinary teams of healthcare professionals. By working together, professionals can develop a personalized treatment plan and provide specialized equipment to maximize mobility, comfort, and independence.
In supporting the treatment plan for ALS, doctors may prescribe medications approved by the U.S. Food and Drug Administration (FDA). These medications include:
- Riluzole (Rilutek): This oral medication reduces motor neuron damage by decreasing levels of glutamate, a chemical that transmits messages between nerve cells and motor neurons. Clinical trials have shown that riluzole may prolong survival by several months. For swallowing difficulties, a thickened liquid form (Tiglutik) or a dissolvable tablet (Exservan) may be preferred.
- Edaravone (Radicava): Available in oral or intravenous form, this antioxidant has demonstrated the ability to slow functional decline in some individuals with ALS.
- Sodium phenylbutyrate/taurursodiol (Relyvrio): This oral medication prevents nerve cell death by blocking stress signals in cells. It has shown effectiveness in slowing functional decline and extending survival in certain individuals with ALS.
- Tofersen (Qalsody): Administered through spinal injection, this treatment is specifically used for ALS patients with a known mutation in the SOD1 gene. While the benefits of this drug are still being studied, it may help reduce one of the indicators of neuronal damage.
