What is amyotrophic lateral sclerosis?
Amyotrophic lateral sclerosis (ALS) is a group of rare neurological diseases that mainly involve the nerve cells (neurons) responsible for regulatory voluntary muscle movement. Voluntary muscles produce actions like chewing, walking, and talking. The disease is progressive, which means that symptoms get worse over time. Now, there is no cure for amyotrophic lateral sclerosis and no effective treatment to stop or reverse the progression of the disease.
Amyotrophic lateral sclerosis goes to a larger group of disorders known as motor neuron diseases, which are caused by the gradual deterioration (degeneration) and death of motor neurons. Motor neurons are nerve cells that extend from the brain to the spinal cord and muscles throughout the body. These motor neurons initiate and provide vital communication links between the brain and voluntary muscles.
Messages from motor neurons in the brain (called upper motor neurons) are transmitted to motor neurons in the spinal cord and motor nuclei in the brain (called lower motor neurons) and from the spinal cord and motor nuclei in the brain to a muscle or muscles in particular.
In amyotrophic lateral sclerosis, both the upper motor neurons and the lower motor neurons decadent or die and stop sending to the muscles. Unable to function, muscles gradually weaken, begin to contract (called fasciculations), and wear out (atrophy). Finally, the brain loses its ability to initiate and control voluntary movements.
Symptoms of amyotrophic lateral sclerosis
The signs and symptoms of amyotrophic lateral sclerosis vary greatly from person to person, depending on the neurons affected. Signs and symptoms can include:
- Difficulty walking or doing normal daily activities
- Stumble and fall
- Weakness in the leg, feet, or ankles
- Weakness or clumsiness in the hands
- Difficulty speaking or difficulty swallowing
- Muscle cramps and spasms in the arms, shoulders, and tongue
- Crying, laughing, or yawning inappropriately
- Cognitive and behavioral changes
Amyotrophic lateral sclerosis often begins in the hands, feet, or extremities and then spreads to other parts of the body. As the disease progresses and nerve cells are destroyed, the muscles weaken. This eventually affects chewing, swallowing, speaking, and breathing.
There is usually no pain in the early stages of amyotrophic lateral sclerosis, and pain is rare in the later stages. ALS does not usually affect bladder control or the senses.
Causes of amyotrophic lateral sclerosis
Researchers still don’t know precisely what causes motor neurons to die with amyotrophic lateral sclerosis. Genetic changes, or mutations, are behind 5% to 10% of amyotrophic lateral sclerosis cases. Additional than 12 different genetic changes have been linked to amyotrophic lateral sclerosis.
One change is in a gene that makes a protein called SOD1. This protein can be toxic to motor neurons. Other genetic changes in ALS can also damage motor neurons.
The setting could also play a role in amyotrophic lateral sclerosis. Scientists are learning whether people who come into contact with certain chemicals or germs are more probable to get the disease.
Scientists are also watching at these other possible causes:
Glutamate: This chemical sends signals to and from the brain and nerves. It is a type of neurotransmitter. With amyotrophic lateral sclerosis, glutamate builds up in the spaces around nerve cells and can damage them. The medications riluzole (Rilutek) work by lowering glutamate levels and may help slow the development of the disease.
Immune system problems: Your immune system protects your body from foreign invaders like bacteria and viruses. In your brain, microglia are the main type of immune cell. They destroy germs and damaged cells. With amyotrophic lateral sclerosis, microglia may also destroy healthy motor neurons.
Mitochondria problems: Mitochondria are the parts of your cells where energy is produced. A problem with them could lead to amyotrophic lateral sclerosis or make an existing case worse.
Oxidative stress: Your cells use oxygen to produce energy. Some of the oxygen your body uses for energy can be converted into toxic substances called free radicals, which can damage cells. The drug edaravone (Radicava) is an antioxidant that can help control these free radicals.
Risk factors of amyotrophic lateral sclerosis
Established risk factors for ALS include:
Heritage: Between five and 10 percent of people with amyotrophic lateral sclerosis inherited it (familial ALS). In most people with familial ALS, their children have a 50 to 50 chance of developing the disease.
Years: The risk of ALS increases with age and is most common between the ages of 40 and mid-60.
Sex: Before age 65, slightly more men than women develop ALS. This sex difference disappears after age 70.
Genetics: Some studies that looked at the entire human genome found many similarities in the genetic variations of people with familial ALS and some people with non-inherited ALS. These genetic variations can make people more susceptible to ALS.
Environmental factors, such as the following, can trigger ALS:
Of smoking: Smoking is the only probable environmental risk factor for ALS. The risk appears to be higher for women, especially after menopause.
Exposure to environmental toxins: Some evidence suggests that exposure to lead or other substances in the workplace or at home could be related to amyotrophic lateral sclerosis. Many studies have been done, but no single agent or chemical has been consistently associated with ALS.
Military service: Studies indicate that people who have served in the military are at increased risk for amyotrophic lateral sclerosis. It is not clear which of the military service could trigger the development of ALS. It can include exposure to certain metals or chemicals, traumatic injuries, viral infections, and heavy exertion.
Diagnosis of amyotrophic lateral sclerosis
Diagnosing amyotrophic lateral sclerosis is problematic because there is no single medical test for it. Also, since many neurological diseases cause similar symptoms, these other conditions must first be ruled out by clinical examinations and medical tests. A complete diagnostic study includes most, if not all, of the following tests and procedures:
Electrodiagnostic tests counting electromyography (EMG) and nerve conduction velocity (NCV), which assess complicated areas such as the bulbar region (head, neck, and brain for speaking and swallowing) as well as the cervical region (arms, diaphragm ), thoracic region (breathing muscles) and lumbar region (legs)
Blood and urine studies, including high-resolution serum protein electrophoresis, thyroid, and parathyroid hormone levels, and 24-hour urine collection for heavy metals, to rule out any immune or inflammatory disease.
- Lumbar puncture
- X-rays and/or magnetic resonance imaging (MRI)
- CT scan of the cervical spine
- Muscle and/or nerve biopsy
- Thorough neurological examination
Individual physicians will determine which of the above tests to perform, usually based on physical examination and the results of prior medical tests that have been performed on the patient.
Treatment and prevention
There is no cure for amyotrophic lateral sclerosis, so treatment aims to relieve symptoms, prevent unnecessary complications, and slow the progression of the disease. Amyotrophic lateral sclerosis can cause a diversity of physical, mental, and social changes, so a team of specialists will often help patients manage their symptoms and care, improve their quality of life, and prolong survival.
Riluzole (Rilutek) was approved for the treatment of amyotrophic lateral sclerosis by the Food and Drug Administration (FDA) in 1995, and it appears to slow the progression of the disease. It can work by reducing the body’s levels of glutamate, an excitotoxin that has been linked to neuronal damage. In May 2017, Radicava (Edaravone) was accepted to treat ALS. It can slow the decline in physical function by one-third.
Various research projects are looking for ways to use new and existing medications to treat different aspects of ALS. Physicians can also recommend medications to treat the different symptoms.
Therapy: Physical therapy can help people with ALS manage pain and address mobility problems. A physical therapist can provide help and information with low-impact exercises to improve cardiovascular fitness and general well-being mobility aids, such as walkers and wheelchair devices to make life easier, such as ramps.
Occupational therapy can help a patient maintain their independence longer by help patients select adaptive equipment and assistive skills to help them maintain their daily routines train them to compensate for hand and arm weaknesses. Respiratory therapy may be needed over time, as the respiratory muscles weaken.
Breathing devices can help the patient breathe better at night. Some patients may require mechanical ventilation. One end of a tube connects to a respirator, while the other end is inserted into the trachea through a surgically created hole in the neck or tracheostomy.
Speech therapy is helpful when ALS begins to make speech difficult. Speech therapists can help by teaching adaptation techniques. Other communication methods include computer and written communication equipment.
Nutritional support is important, as difficulty swallowing can make it difficult to get enough nutrients. Nutritionists can advise on preparing nutritious meals that are easier to swallow. Suction devices and feeding tubes can help.
Complications of amyotrophic lateral sclerosis
By way of the disease progresses, ALS causes complications, such as:
Respiratory problems: Over time, amyotrophic lateral sclerosis paralyzes the muscles you used to breathe. You may need a device to help you breathe at night, similar to what a person with sleep apnea might use. For example, you may be given continuous positive airway pressure (CPAP) or bi-level positive airway pressure (BiPAP) to help you breathe at night.
Some people with advanced amyotrophic lateral sclerosis choose to undergo a tracheostomy, a surgically created hole in the front of the neck that leads into the windpipe (windpipe), for full-time use of a ventilator that inflates and deflates their lungs.
The most mutual cause of death for persons with ALS is respiratory failure. On average, death occurs three to five years after symptoms begin. However, some people with ALS live 10 years or more.
Trouble speaking: Most people with ALS develop trouble speaking. Usually, this starts out as an occasional slight drag of words but becomes more severe. Over time, speech becomes difficult for others to understand, and people with ALS often rely on other communication technologies to communicate.
Eating problems: People with ALS can progress malnutrition and dehydration from injury to the muscles that control swallowing. They are also at increased risk of getting food, liquid, or saliva into the lungs, which can cause pneumonia. A feeding tube can reduce these risks and ensure adequate hydration and nutrition.
Dementia: Some people with amyotrophic lateral sclerosis have problems with memory and decision-making, and some are eventually diagnosed with a form of dementia called frontotemporal dementia.