brain, spinal cord, and nerve disorders
Amyotrophic Lateral Sclerosis (ALS) and Other Motor Neuron Diseases (MNDs)
Symptoms
Muscle strength is affected, but people do not have pain or any changes in sensation. Depression is common. This progressive form begins with weakness, often in the hands and less frequently in the feet or mouth and throat. Weakness may progress more on one side of the body than on the other and usually proceeds up the arm or leg. Muscles, usually those in the hands and feet, start to waste away (atrophy). Muscle cramps are also common and may occur before the weakness, but no changes in sensation occur. People lose weight and feel unusually tired. Over time, weakness increases. When amyotrophic lateral sclerosis affects motor nerves in the brain, muscle tone typically increases, and muscles tend to become stiff and tight, leading to muscle spasms (called spasticity). Movements are stiff and clumsy. When motor nerves in the spinal cord are affected, muscle tone decreases, making the limbs seem loose and floppy. When the connection between motor nerves and muscles is lost, the muscles twitch spontaneously (called fasciculations). Controlling facial expressions may become difficult. Weakening of muscles in the throat may lead to slurred speech and difficulty swallowing (dysphagia). Because swallowing is difficult, people sometimes drool and are more likely to choke on liquids. Food or saliva can be inhaled (aspirated) into the lungs, increasing the risk of pneumonia (called Aspiration Pneumonia and Chemical Pneumonitis ). The voice usually sounds nasal but may be hoarse. As symptoms progress, people may be unable to control emotional responses and may laugh or cry inappropriately. Eventually, the muscles involved in breathing weaken, leading to breathing problems. Some people need a ventilator to breathe. How rapidly amyotrophic lateral sclerosis progresses varies: About 50% of people with the disorder die within 3 years of the first symptoms. About 20% live 5 years. About 10% live 10 years or more. A few people survive more than 30 years. These motor neuron diseases are rare, slowly progressive variants of amyotrophic lateral sclerosis: Primary lateral sclerosis affects mainly the arms and legs. Progressive pseudobulbar palsy affects mainly the muscles of the face, jaw, and throat. In both disorders, muscles are weak and very stiff and tight (spastic), but muscle twitching (called fasciculations) and wasting do not occur. Emotions may be changeable: People with progressive pseudobulbar palsy may switch from happiness to sadness quickly and without reason. Inappropriate emotional outbursts (for example, sudden laughter or crying) are common. Symptoms usually progress for several years before total disability results. Progressive muscular atrophy can develop at any age. It is similar to amyotrophic lateral sclerosis, except motor nerves in the brain are not affected. Also, it progresses more slowly, spasticity does not occur, but muscles weaken, become limp (flaccid), and waste away. Involuntary contractions or twitching of muscle fibers (fasciculations) may be the earliest symptoms. The hands are usually affected first, followed by the arms, shoulders, and legs. Eventually, the whole body is affected. Many people with this form survive 25 years or longer. In progressive bulbar palsy, the nerves controlling the muscles of chewing, swallowing, and talking are affected, making these functions increasingly difficult. The voice may have a nasal tone. In some people, emotions are changeable. Because swallowing is difficult, food or saliva is often inhaled into the lungs, causing choking or gagging and increasing the risk of Aspiration Pneumonia and Chemical Pneumonitis . Death, which is often due to pneumonia, usually occurs 1 to 3 years after symptoms appear. 