The 3 stages of amyotrophic lateral sclerosis (ALS)

Amyotrophic lateral sclerosis (ALS) is a disease that affects the brain and spinal cord, causing progressive loss of muscle function and control. The abilities to walk, talk and swallow are gradually impaired to the point of being completely lost.

ALS is a disease whose exact causes are still unknown, but it has multiple contributing factors: genetic and environmental. Although there is currently no known cure, there are therapies that can help people diagnosed with ALS live longer and improve their quality of life.

There are two main types of ALS whose symptoms manifest in specific phases. In this article, we will talk in detail about the different stages of ALS as a pathology that unfolds its symptoms over time.

    What is ALS?

    Amyotrophic lateral sclerosis is a degenerative disease that attacks the nervous system and produces the progressive loss of motor functions. Worldwide, the prevalence of ALS is 5 in 100,000 people, so it is considered a rare disease.

    It is a progressive disease, but the progression of symptoms may differ from person to person. Nerve cells called motor neurons or motor neurons control voluntary muscle actions in different parts of the body, such as the arms, legs and face, and ALS affects these nerve cells, which gradually lose function and eventually die. then, the messages that are sent by motor neurons stop being sent and the brain’s ability to control voluntary movements is lost. Over time, when not used, the muscles begin to degenerate and weaken.

    Although progressive muscle weakness is a symptom that occurs in all patients diagnosed with ALS, it may not be the first sign or indication of the disease.

    The progression of the disease varies between people, and the beginnings of the disease can be difficult to notice, since no manifestation is seen. Over time, the signs and symptoms of the disease become more evident. Some of the first noticeable symptoms include clumsiness, unusual limb fatigue, muscle cramps and spasms, and difficulty speaking. Symptoms spread throughout the body as the disease progresses.

    Brain function deteriorates over time and in some people with ALS this can lead to a form of dementia, known as frontotemporal dementia. In addition, people’s decisions and memory can also be compromised as the disease progresses. When it comes to psychological functions, the emotional lability that results from illness can also cause people to have more variable moods and emotional responses.

      ALS stages

      There is no cure for ALS. The average lifespan of an ALS patient is 3 years after diagnosis. 20% will live 5 years and 10% 10 years. Only 5% of people with ALS live 20 years or more. The majority of diagnosed patients die within 2 to 10 years of diagnosis, due to respiratory failure resulting from progressive loss of function.

      There is no official definition of the stages of ALS, as the disease progresses differently for each patient. Some people experience different symptoms at different times, and the progression of the disease and its consequences are variable, some people will lose their functions more quickly than others. I say this, in general terms, ALS can be divided into three stages: early, intermediate and late.

      early stage

      Although there are cases of early onset, the average age of onset of the disease is 50 years. The disease initially progresses slowly and often does not cause painwhich can cause patients to delay their visit to the doctor for a long time.

      If the first symptoms affect the patient’s speech or ability to swallow, then it is called “bulbar ALS”.

      If the hands and feet are the first affected and there are abnormal muscle movements, we speak of “ALS of the extremities”,

      Sometimes the disease begins with loss of body weight or muscle mass, or with abnormal breathing. About 3% of patients have breathing problems as the first symptom.

      At first, people usually experience muscle weakness, stiffness, and cramps. Since there is no linear progression of the disease, some people may have more symptoms than others. People can be prevented from carrying out daily tasks because the symptoms affect the muscles: ALS patients may fall, drop objects or be unable to button their shirt.

        Intermediate stage

        ALS is a variable disease in its development. Sometimes the progression is slow, spread over years and has periods of stability with different levels of disability. Other times it’s fast and there are no steady periods.

        During this phase of ALS, different symptoms can be experienced: there are difficulties in swallowing and breathing. Muscles can be paralyzed, muscle loss is felt and even these can become shorter. Joints lose motion, speech becomes slower, and patients may laugh or cry in ways they cannot control.

        Speech, swallowing and breathing are long-term effects of the disease: ALS patients often show signs of bulbar involvement when weakness and paralysis spread to the muscles of the trunks of their body.

        The patient may completely lose the ability to speak and have difficulty swallowing, and a reduced ability to cough. These problems expose patients to various respiratory problems (asphyxia, respiratory infection, pneumonia) and malnutrition.

        As the disease progresses, the muscles used for breathing can deteriorate and lose function, requiring the patient to use a ventilator for life.

        The muscle changes a person may experience during the early stages of ALS may worsen during the middle stages of the disease. This means that the symptoms can also affect other parts of the body. Patients increasingly need help with daily activities when the disease enters this phase.

        The patient will be cared for by several specialized teams. Today, pulmonology has made great progress, which can improve the quality of life of the patient at this stage of ALS.

          Later steps

          Over time, the patient becomes fully aware of his disease and its evolution. Often, this awareness causes psychological problems related to fear of death and physical disability. The patient may suffer from anxiety or depression. Quality of life is one of the main goals of ALS treatment, since the patient and his family must face all aspects of the disease together.

          When the patient has ALS, he becomes completely dependent on others. Patients and their families must face all phases of the disease with the help of specialized professionals.

          When a person reaches the later stages of the disease, all of their muscles begin to paralyze, including those in the throat and mouth. This makes it impossible to speak, eat or drink. A tube may be needed to deliver food and drink to the person.

          The patient may also develop the following complications: respiratory failure, malnutrition and pneumonia.

          Some people with ALS also develop frontotemporal dementia (FTD), while others who are initially diagnosed with FTD develop symptoms of ALS, FTD is also a progressive disorder that affects speech, behavior and personality.


          ALS is a disease that affects the neurons that control movement and produces the progressive loss of motor functions.

          There is no cure for ALS, it is considered a progressive disease. Although its stages are not officially defined, since it is a disease that is quite variable in the appearance of symptoms and their evolution.

          Generally speaking, amyotrophic lateral sclerosis can be divided into three stages. In the early stages, it can cause muscle spasms or weakness. In the later stages, there may be paralysis, breathing problems, or loss of muscle mass. The most common cause of death is respiratory failure resulting from loss of function.

          People with ALS can improve their lives by using different treatment options that also include mental health support.

          Bibliographic references

          • Brotman, RG, et al. (2020). Amyotrophic Lateral Sclerosis [Abstract].
          • Marcu, IR, et al. (2018). Diagnostic particularities of amyotrophic lateral sclerosis in an elderly patient
          • Nguyen, HP, et al. (2018). ALS genes in the genomic era and their implications for FTD.

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