Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disease that primarily affects the motor neurons in the brain and spinal cord. This disease leads to the gradual atrophy and loss of function of motor neurons, ultimately resulting in muscle weakness, paralysis, and in severe cases, life-threatening conditions. The progression of ALS varies; some patients may experience rapid deterioration within a few years, while others may progress slowly. Currently, there is no cure, but early diagnosis and multidisciplinary treatment can effectively delay symptom progression and improve the quality of life for patients.
ALS primarily affects the neurons that control voluntary muscle movements, including upper motor neurons (located in the brain and spinal cord) and lower motor neurons (located in the spinal cord and brainstem). When these neurons are damaged, muscles cannot receive nerve signals, leading to gradual atrophy and loss of control. The disease typically manifests in middle or older age, although a small number of cases may occur in younger populations. According to statistics, approximately 2 to 3 people per 100,000 are diagnosed globally each year, with a male-to-female ratio of about 2:1. Although the exact cause of ALS is not fully understood, the interplay of genetic, environmental, and biological factors is considered crucial.
About 5-10% of ALS patients have a family history of the disease, with approximately 20% associated with specific gene mutations, such as SOD1, C9ORF72, and TARDBP genes. These genetic abnormalities may lead to protein accumulation or metabolic dysfunction, triggering neuronal death. Familial ALS typically presents at a younger age, and multiple generations in a family may have similar cases.
The causes of sporadic ALS are more complex and may involve various mechanisms, including oxidative stress, protein misfolding, and neuroinflammatory responses. Recent studies suggest that dysfunction in the intracellular glutathione system may lead to decreased antioxidant capacity, accelerating neuronal damage.
The early symptoms of ALS are often subtle and easily overlooked. Patients may first experience unilateral limb weakness, such as difficulty controlling hand muscles, leading to challenges in writing or buttoning clothes. Approximately 40% of patients report their initial symptoms in the hands, while 30% may start with leg symptoms, such as tripping or unsteady gait. Additionally, some patients may experience muscle fasciculations or atrophy, but these early symptoms may be misdiagnosed as fatigue or sports injuries.
Speech and swallowing functions may also be affected. About 25% of patients experience slurred speech (dysarthria) at the onset, with a hoarse voice or slowed speech, impacting daily communication. Swallowing difficulties (dysphagia) may lead to prolonged eating times or the sensation of food getting stuck.
As the disease progresses, symptoms gradually spread throughout the body. Patients may completely lose the ability to walk and need to rely on a wheelchair for mobility. Damage to the respiratory muscles can lead to inadequate ventilation, and patients may require respiratory assistance. When swallowing and speaking functions severely deteriorate, communication and nutritional intake may need to be managed through gastrostomy or speech-assisted devices.
The diagnosis of ALS requires the exclusion of other neurological diseases, thus the diagnostic process involves multiple steps. First, a neurologist will conduct a detailed medical history inquiry and physical examination to assess muscle strength, reflex responses, and the presence of muscle atrophy. Electrophysiological tests such as electromyography (EMG) and nerve conduction velocity tests can confirm the extent of motor neuron damage.
Imaging studies such as MRI and muscle/nerve biopsies are used to rule out multiple sclerosis, spinal cord injuries, or other neurodegenerative diseases. Blood tests are used to screen for genetic mutations or metabolic abnormalities. The diagnostic criteria rely on the "El Escorial criteria," which require observation of simultaneous damage to both upper and lower motor neurons, with lesions present in at least two different spinal cord segments.
The only FDA-approved medications currently are riluzole and edaravone, both of which can slow neuronal damage but cannot completely halt disease progression. Riluzole reduces oxidative stress on nerve cells by inhibiting the excessive release of excitatory amino acids, while edaravone has antioxidant properties. Clinical trials have shown that these medications can extend patient survival by approximately 2-3 months on average.
Symptom management is central to treatment. Muscle spasms can be alleviated with baclofen or diazepam; sialorrhea can be improved with anticholinergic medications. When respiratory function declines, bronchodilators or respiratory assistance may be required. For nutritional support, dietitians will design high-calorie diets based on swallowing ability, and in severe cases, feeding may need to be done via a gastrostomy tube.
Stem cell therapy and gene therapy are currently hot research topics. Stem cell transplantation aims to replace damaged motor neurons, while gene therapy seeks to correct genetic mutations associated with familial ALS. Additionally, neuroprotective agents such as ciltacabtagene autotemcel are in clinical trials, attempting to slow neuronal death by modulating immune responses.
Currently, there is no evidence that specific measures can prevent ALS, but avoiding known risk factors may reduce potential risks. It is recommended to minimize exposure to pesticides, heavy metals, and industrial chemicals, especially for those who work long-term in agriculture or chemical industries. Maintaining regular exercise and a balanced diet can help sustain the antioxidant capacity of nerve cells.
Individuals with a family history should undergo genetic counseling and testing, especially if they are carriers of known mutated genes. Regular neurological examinations are advised, and if unexplained muscle weakness or cramps occur, early medical evaluation should be sought. Although complete prevention is not possible, early detection and treatment can significantly improve quality of life.
Seek medical attention promptly if the following symptoms occur: persistent unexplained muscle weakness for several weeks, unexplained weight loss, significant deterioration in hand coordination, or persistent hoarseness when speaking. While these symptoms may be caused by other factors, early assessment can rule out or confirm ALS and initiate treatment.
If there have been cases of ALS in the family, even mild symptoms should warrant a genetic risk assessment. Physicians may recommend electrophysiological tests or genetic testing to differentiate ALS from other motor neuron diseases, such as spinal muscular atrophy (SMA) or multiple sclerosis (MS).
Early symptoms of ALS, such as muscle weakness or fasciculations, may be confused with multiple sclerosis or spinal cord injuries. The key is to assess the selective involvement of motor neurons, such as fine motor difficulties in the hands accompanied by fasciculations, which usually require confirmation through electrodiagnostic and neuroimaging studies. It is advisable to seek medical attention promptly if persistent unexplained muscle atrophy occurs.
What emerging treatments are available to alleviate symptom progression?Recent studies indicate that, in addition to traditional medications like Riluzole, antioxidants such as EDARAVONE have been shown to slow functional decline in some patients. Gene therapy and neuroprotective therapies are currently in clinical trial stages, and patients are encouraged to discuss the indications and risks of the latest therapies with their healthcare providers.
What measures can effectively improve the quality of life for patients in daily care?Physical therapists recommend regular passive exercises to prevent joint contractures, and speech therapists can assist with swallowing and communication skills training. Using specialized aids such as speech synthesizers and electric wheelchairs can enhance mobility independence. Family members should learn proper handling techniques to avoid secondary injuries.
Does dietary adjustment help slow disease progression?While there is a lack of direct evidence showing that specific diets can treat ALS, balanced nutrition can maintain muscle energy supply and slow muscle atrophy caused by malnutrition. Patients may need to choose soft or semi-liquid foods due to swallowing difficulties, and consulting a dietitian for an individualized meal plan may be necessary.
What psychological support resources are available for patients and families?Patients often experience anxiety due to the irreversible nature of the disease, and it is recommended to participate in dedicated support groups or consult clinical psychologists. In Taiwan, several ALS patient associations provide free counseling and resource connections, and hospital social workers can assist in applying for long-term care subsidies. Psychological support and medical care should be conducted concurrently.
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