What do Usain Bolt, Ethel Kennedy, Justin Bieber and the Cookie Monster all have in common? They are just a few of the thousands of people that have participated in the ice bucket challenge: an Internet sensation that has been used to promote awareness of amyotrophic lateral sclerosis in 2014.
Amyotrophic lateral sclerosis (ALS) is a progressive neurological disease that causes dysfunction of the nerves that control muscle movement. Over time, this leads to muscle weakness, gradually affecting how the body functions. In the late stages of ALS, the condition affects nerves that control breathing and other vital bodily functions, resulting in death.
ALS is the most common type of motor neuron disease (MND); in the US, most people use the term ALS to mean MND. ALS is sometimes also referred to as Lou Gehrig's disease, after the famous baseball player who had the condition.
The disease was first discovered in 1869 by the French neurologist Jean-Martin Charcot, and first written about in 1874, but it was the impact on Gehrig's career that truly brought ALS into public awareness in 1939.2
According to the ALS Association, about 6,400 people are diagnosed with the condition every year in the US, with an estimated 20,000 living with ALS at any one moment.3
This Medical News Today article will give you the essential details about ALS. You will also see introductions at the end of some sections to any recent developments that have been covered by MNT's news stories. Also look out for links to information about related conditions.
Here are some key points about ALS. More detail and supporting information is in the main article.
- ALS affects nerve cells found in the brain and spinal cord, leading to muscle weakness, a gradual loss of motor function and, eventually, death.
- The average life expectancy of ALS patients after diagnosis is between 2-5 years.
- No one knows what causes ALS, but environmental and genetic factors are thought to be involved.
- Common symptoms of ALS include weakness in the limbs and difficulties with speech and breathing.
- Progressive muscle weakness and paralysis eventually occur in all people with ALS.
- ALS is usually diagnosed based on presenting symptoms while ruling out other illnesses.
- There is currently no cure for ALS. Treatment focuses on the alleviation of symptoms, and possibly slowing down the rate of ALS progression.
- As ALS causes a range of physical, social and psychological symptoms, multidisciplinary care teams are important.
- As well as physical treatment, it is important for ALS patients to receive social and psychological support.
- The ice bucket challenge raised around $115 million dollars in asix-week period in 2014. The ALS Association has already allocated around $47.5 million of that money to research projects investigating ALS.
What is ALS?
ALS belongs to a group of diseases called motor neuron diseases. It is a disease that attacks the nerve cells that are used in voluntary muscle actions; actions that we can control such as those in the arms, face and legs.4
As ALS progresses, motor neuron cells in the body degenerate and die.
These nerve cells are called motor neurons and are found in the brain and spinal cord. As ALS progresses, these cells degenerate and die, ceasing to send messages to muscles, which in turn causes them to weaken and waste away.
The brain's ability to control voluntary movement is lost, with all muscles under voluntary control affected as the disease progresses. As well as control of the arms, face and legs, ALS can cause people to lose the ability to breathe unsupported, often leading to respiratory failure.
ALS greatly reduces an individual's life expectancy; most people die within 2-5 years of diagnosis.
There are, however, many examples of people living for much longer, however. After ALS diagnosis, around 20% of people will live five years or more, 10% will live for 10 years or more and 5% will live for a further 20 years.3
Causes of ALS 3,4,5
Currently, experts do not know precisely what causes ALS. It can affect anyone, regardless of gender, race, ethnicity or geographical location. There are two types of ALS: sporadic (randomly occurring) and familial.
Familial ALS accounts for around 10% of cases and is inherited, with the offspring of a person with ALS having a 50% chance of developing the condition.In addition to genetic factors contributing to the heritability of familiar ALS, researchers are investigating several possible causes of ALS, including:
- Disorganized immune response: the immune system may attack some of the body's cells, potentially killing nerve cells
- Chemical imbalance: people with ALS often have higher levels of glutamate, a chemical messenger in the brain, near the motor neurons. Glutamate in high quantities is known to be toxic to nerve cells
- Mishandling of proteins: if proteins are not processed correctly by nerve cells, abnormal proteins could potentially accumulate and cause the nerve cells to die.
According to the National Institute of Neurological Disorders and Stroke (NINDS), researchers are also investigating whether environmental factors play a role in the development of ALS. For example, a study reported that military personnel deployed in the Gulf region during the 1991 war were more likely to develop ALS than military personnel deployed elsewhere.
Environmental and lifestyle factors likely play a role in the development of ALS, but no conclusive evidence is available to support making specific changes to decrease the risk of the disease. Some possible links have been found between ALS and exposure to:14
- Mechanical or electrical trauma
- Military service
- High levels of exercise
- High levels of agricultural chemicals
- High levels of a variety of heavy metals.
A study that examines an overlooked area of research in ALS, or Lou Gehrig's disease, reveals a new way in which the devastating and incurable neurological condition kills nerve cells.
A new study provides the first evidence-based description of a type of protein clump thought to play an important role in ALS, or Lou Gehrig's disease, by killing the nerve cells that control movement.
Despite furious research, the exact causes of Lou Gehrig's disease are yet to come to light. New research published in the journal Science slots a new piece into the puzzle.
The nerve cells of some people with the serious disorder amyotrophic lateral sclerosis can accumulate clumps of a protein called SOD1. A mutation in the SOD1 gene is known to cause the disease, but it has not been clear if the characteristic clumps of the protein associated with the faulty gene are active drivers or harmless byproducts of the disease. Now, a new study suggests they are drivers.
On the next page we look at the signs and symptoms of ALS and how it is diagnosed. On the final page we discuss the treatments for ALS and the impact of the ice bucket challenge.