Amyotrophic lateral sclerosis, or ALS, is a progressive neurodegenerative disease affecting the nerve cells in the brain and spinal cord. It is commonly known as Lou Gehrig's disease, named after the famous New York Yankee who was forced to retire in 1939 after developing symptoms. According to the CDC, about 32,000 adults live with ALS in the United States . It affects men more than women, and while there is a 50 percent chance that the children of someone with ALS will also develop the disease, there is no known family history in most cases.
ALS is a progressive disease that affects the motor neurons , causing the muscles to weaken and eventually waste away. Early symptoms include muscle twitches, weakness, and difficulty speaking, swallowing, or breathing. As the disease progresses, symptoms worsen and can include being unable to stand or walk, get out of bed independently, or use the arms and hands. Chewing food, swallowing, and speaking may become difficult, and maintaining weight and proper nourishment can be challenging. People with ALS eventually lose their ability to breathe on their own and will become ventilator-dependent. ALS generally does not affect a person's ability to think, remember, reason, or understand, so they typically remain aware of their disease progression, which can greatly affect their mental health and daily lives.
There is no definitive test for diagnosing ALS . The doctor will do a thorough exam, including an extensive family history and testing reflexes and muscle strength. Some diagnostic tests can confirm a suspected ALS diagnosis, including electromyography (EMG), which detects electrical activity in the muscle fibers, and a nerve conduction study (NCS), which measures the electrical activity in the nerves and muscles to determine if the nerves can send signals properly. Many diseases can mimic the symptoms of ALS, including myasthenia gravis, spinal muscular atrophy, Lambert-Eaton syndrome, and poliomyelitis. The fact that there is no definitive test for ALS, combined with the number of conditions that mimic its symptoms, can make diagnosing ALS challenging.
Most cases of ALS are considered sporadic ALS, which means that the disease seems to occur randomly in people with no family history of the disease and no associated risk factors. People with sporadic ALS usually develop symptoms in their late fifties or early sixties.
About five to ten percent of ALS cases are familial or genetic. People with familial ALS usually develop symptoms in their late forties or early fifties. Although rare, some people with familial ALS can develop symptoms as early as childhood.
There are multiple subtypes of ALS that determine the pattern and progression of symptoms and may inform the prognosis. The most common type is limb onset, which affects about 70 percent of people with ALS. Limb onset ALS that starts in the upper extremities usually begins close to the body and progresses down the arm to the hand until the limbs are severely impaired. It can also begin in the lower extremities, starting in the toes and feet and working its way up the legs. About 25 percent of ALS cases are bulbar onset, which affects the cranial nerves; in this subtype, some of the earliest symptoms are speech and swallowing difficulties. The limbs are involved as the disease progresses. Another type of ALS is primary lateral sclerosis, which has a slower progression. People with this subtype may not have severe symptoms in the first four years of the disease, but they will develop them eventually.
The stages of progression vary for every person with the disease, including how fast and in what order symptoms appear. Some people with ALS may have periods or weeks to months with little loss of function, but once ALS starts, it almost always progresses. In the early stages, people with ALS may experience muscle weakness or stiffness. These symptoms progress in the middle stage, increasing to weakness, wasting, and paralysis. In the late stage, the muscles of the trunk and those that control vital bodily functions are affected, and the person will likely require a ventilator. There is no timeline for how long each stage will take, but the type and subtype of ALS may contribute to the prognosis.
Unfortunately, there are no medications that can stop or reverse ALS, but several drugs have obtained FDA-approval and may slow progression or prolong the life of people with ALS. For example, studies on sodium phenylbutyrate–taurursodiol found that it slowed functional decline by more than 25 percent and resulted in a 6.5-month longer survival time than a placebo. Another drug can prolong the life of someone with ALS by an average of three months. Physical therapy for ALS may focus on preventing falls, stretching, doing a range of motion exercises, educating about proper positioning and joint support, assisting with exercise, and teaching airway clearing techniques. Respiratory care is also essential to treating ALS, especially as the disease progresses. Such care can include multiple interventions, including breathing techniques, coughing techniques, coughing equipment, and mechanical ventilation.
Many people with ALS eventually get a feeding tube, a tube that is inserted through the skin into the stomach or intestines. Feeding tubes may be necessary when oral nutrition or hydration is insufficient or when the person has difficulty chewing or swallowing to the point that eating leads to fatigue or aspiration. Doctors may recommend having a feeding tube placed before one is needed to ensure that the person will be able to fully recover from the procedure. People with ALS also need to make decisions about their end-of-life care. Advanced directives are important as they let the person's wishes be known while they can still communicate. The goals of end-of-life care for someone with ALS include alleviating prolonged discomfort, optimizing quality of life, and making them at ease with dying.
Generally, most people with ALS survive between two and five years, but some can live for twenty years or longer. Factors that indicate a poor prognosis may include early onset, being single, smoking history, bulbar onset, and rapid deterioration. Factors that benefit prognosis may include atypical presentation and diagnosis delay time and disease duration, which may be because the more prolonged symptoms are present without a diagnosis, the slower the disease is likely progressing. Quality of life in ALS may be directly related to integrity and functional independence, and it is essential to remember that quality of life must reflect the views of the patient.
There have been significant advances in ALS genetic research, with researchers making considerable progress in understanding the genetics and pathophysiology behind the disease, which may open the door to more treatment possibilities. Cases have been identified, and many drugs are being developed, including genetic therapies to alter gene expression.
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