Amyotrophic lateral sclerosis
Table of Content:
- What is amyotrophic lateral sclerosis?
- Who gets ALS?
- What causes ALS?
- What are the symptoms?
- Risk Factors & Complications
- How is ALS diagnosed?
- How is ALS treated?
What is amyotrophic lateral sclerosis?
“Amyotrophic’ means “without nourishment to the muscles”, and comes from Greek roots. Amyotrophic lateral sclerosis, also known as Lou Gehrig’s disease after the baseball player who was affected by it, is a progressive neurological disorder characterised by loss of control of skeletal muscles of the body. It affects the nerve cells of the brain and the spinal cord. ALS often shows symptoms like twitching or slurred speech in the beginning, but as the muscles get weaker, it becomes increasingly harder to walk, talk, or breathe. It has no cure yet and is a fatal condition.
Who gets amyotrophic lateral sclerosis?
Amyotrophic lateral sclerosis or ALS is a common neuromuscular condition and can affect people of all races and ethnic backgrounds. Few potential risk factors have been identified. People in the age-group of fifty five to seventy-five years, those of Caucasian and non-Hispanic origin, and men more than women are more likely to get amyotrophic lateral sclerosis.
About 5-10% of the cases of ALS have shown a familial etiology, meaning it can be inherited from one of the parents. Over a dozen genes have been identified that can cause amyotrophic lateral sclerosis in individuals.
What causes amyotrophic lateral sclerosis?
It is still not known what causes the motor neurons to die in amyotrophic lateral sclerosis. A protein called SOD1 is thought to be toxic to the neurons. Mutations in the gene that makes this protein could be one of the causative factors. Other such genes are being looked into as well. Environmental causes such as exposure to certain chemicals have also been considered as etiological factors. Other areas of research to identify potential causes of amyotrophic lateral sclerosis include:
- Glutamate is a neurotransmitter that sends chemical signals within the brain and the nervous system. In this condition, glutamate accumulates around the motor neurons and leads to damage.
- Immune system defects. The immune system plays a vital role in protection from invading organisms in the body. Microglia, the immune cells of the brain, destroy healthy neuron cells in ALS.
- Defects in the mitochondria. Mitochondria are the energy houses of a cell and their defects are known to be associated with the pathogenesis of amyotrophic lateral sclerosis.
What are the symptoms of amyotrophic lateral sclerosis?
At the onset, the symptoms of amyotrophic lateral sclerosis can be subtle such as:
- Muscle twitches, or fasciculations in the leg, arm, shoulder, or tongue.
- Tightness or stiffness of muscles
- Muscle cramps
- Slurred speech or nasal speech
- Difficulty in chewing or swallowing
Simple activities like buttoning a shirt, turning a key in a lock, or even writing may become difficult. Some people find it awkward to walk and may find themselves tripping or stumbling more often.
When your symptoms first appear in the arms or limbs, it is referred to as “limb onset”, while it is known as “bulbar onset” when the first symptoms are those affecting speech or swallowing. When only the upper motor neurons are affected, the condition is referred to as Primary Lateral Sclerosis.
Irrespective of the first signs of ALS, the disease progresses to symptoms such as difficulty in swallowing, speaking and breathing, and inability to use your arms or legs.
Complications
As ALS progresses, complications arise which include problems such as:
- Breathing difficulty. With time, the muscles that assist breathing are paralysed and the individuals may require devices such as CPAP (continuous positive airway pressure) and BiPAP (Bilevel Positive Airway Pressure) to breathe. A common cause of death for people with ALS is respiratory failure.
- Speech problems. What begins as slurring of speech soon becomes more pronounced and people affected require other technologies to communicate.
- Difficulty in eating. Damage to muscles that control swallowing can cause malnutrition and dehydration. It can also lead to an increased risk of aspiration pneumonia.
How is amyotrophic lateral sclerosis diagnosed?
Amyotrophic lateral sclerosis is usually diagnosed after obtaining a detailed history of the signs and symptoms as well as a physical examination. The presence of upper and lower motor neuron symptoms strongly supports a diagnosis of amyotrophic lateral sclerosis. Here are some of the tests that will be advised if you are a suspected case of ALS:
- Electromyography: An electromyograph is a device that records the electrical activity of muscles. Another test that can be used is the nerve conduction study. These assess the ability of a nerve to send a signal to a muscle.
- Imaging studies: Your physician may require an MRI to rule out the presence of any spinal tumour, cervical spondylosis, or a herniated disc that may cause similar symptoms.
- Laboratory tests. Blood or urine tests will help to rule out the presence of other diseases.
How is amyotrophic lateral sclerosis treated?
No cure for ALS is yet available. However, several ALS treatment options that are available help to reduce the severity of the amyotrophic lateral sclerosis symptoms, prevent complications and make living with the disease easier.
Multidisciplinary teams offer a personalised treatment plan for ALS to keep patients as comfortable, independent, and mobile as possible.
- Medical therapy for ALS: The FDA-approved drugs for ALS include Riluzole and Edavarone. These drugs have been shown to slow the progression of the disease and prolong survival respectively. Other drugs are also prescribed to relieve symptoms such as muscle cramps and stiffness.
- Physiotherapy: Gentle low-impact exercises such as walking and swimming help to improve cardiovascular health as well as keep depression and fatigue away. Special equipment is also provided to enhance an individual’s independence and safety.
- Speech therapy: Speech therapists can help by teaching strategies to speak loudly and clearly. They help in maintaining communication as the disease progresses. Aids such as computer-based speech synthesizers and eye-tracking technology are recommended which help people with advanced disease respond and interact.
- Nutritional support. People with ALS tend to become weak and lose weight. Nutritional support is necessary to prevent further complications. Nutritionists advise caregivers and individuals on how to give small frequent meals that provide sufficient calories, fibre, and nutrients. Feeding tubes are inserted in the later stages to reduce the risk of aspiration pneumonia.
- Breathing support. As the disease progresses, the muscles responsible for breathing may also weaken, requiring assistance from devices such as a CPAP or BiPAP. Doctors may also recommend what is known as non-invasive ventilation, or NIV to facilitate breathing.
Dr. Vikram Huded | Senior Consultant – Neurology | Mazumdar Shaw Medical Center, Bangalore