Amyotrophic lateral sclerosis (ALS) (Charcot disease) is a medical condition characterized by progressive damage to the nerves supplying the different voluntary muscles of the body (motor neuron). It is a progressive disease characterized by gradual degradation of the motor neurons.

Common presenting symptoms include progressive weakening of different muscles of the body due to muscle atrophy, impairment of speech (dysarthria), swallowing reflex (dysphagia) and difficulty in breathing (dyspnoea). There is no cure for the disease and eventually the affected person dies. This disease is considered to be one of the most common diseases affecting the motor neurons (motor neuron disease), other diseases include primary lateral sclerosis, progressive muscular atrophy etc.

Amyotrophic lateral sclerosis is sometimes referred to as Loy Gehrig’s disease after the famous basketball player who suffered from this disease.

Symptoms
Common presenting symptoms of amyotrophic lateral sclerosis include gradual onset of weakening of limbs resulting into difficulty in walking, increased tripping due to lower limb weakness, increased clumsiness due to upper limb weakness, slurring of speech, difficulty in swallowing, painful cramps in the muscles which usually starts with twitching in the arms, tongue or in the shoulders etc. Weakness may progress to such an extent that it becomes difficult for the patient to hold the head high or maintain normal posture.

Muscle weakening is the most common presenting symptom and also it is of the earliest symptoms. However bowel and bladder control remains intact, so is the normal thought process and brain function of the affected person.

Common complications associated with later stage of amyotrophic lateral sclerosis include

1. Breathing difficulty: it occurs due to impaired functioning of the respiratory muscles hence requiring use of respirator especially at the time of sleeping. Sometimes tracheostomy, a hole created in front of the trachea surgically, is done to facilitate round the clock use of respirator at advanced stage of the disease. Respiratory failure is one of the most common reasons of death in these patients and usually the affected people die within 3 to 5 years. However 4% of the affected persons survive for more than 10 years after diagnosis of the disease. Famous physicist Stephen Hawking is diagnosed with amyotrophic lateral sclerosis and is living with the disease for more than 50 years.
2. Speech problem: initially there is only mild slurring of speech which gradually becomes so severe that ultimately the patient has to depend upon other ways of communication.
3. Impaired swallowing: it results into inability to eat adequate amount of food resulting into malnutrition and dehydration. Also the risk of choking increases due to impairment of this reflex. Hence eventually feeding tube becomes essential.
4. In some people of amyotrophic lateral sclerosis severe degree of dementia may occur during the late stage of the disease.

Causes
In this disease the nerves (neurons) which supply the voluntary muscles gradually become degenerated and eventually die.

There are several underlying possible causes of amyotrophic lateral sclerosis namely

1. mutation (sudden irreversible change in the genetic material) of genes
2. high level of glutamate in the brain and the spinal cord, glutamate is known to be toxic to nerves
3. Malfunctioning of the immune system: instead of attacking foreign invading cells, the immune cells of the body wrongly attacks own cells, in this case motor neurons leading to death of these cells and the disease.
4. Mishandling of proteins: usually abnormal proteins produced in the body are destroyed however in some patients of amyotrophic lateral sclerosis, certain abnormal proteins may get accumulated in the nerve cells killing them.

Risk factors
Common risk factors include
1. Hereditary factors: in about 5-10% of the cases of amyotrophic lateral sclerosis there is positive family history. There is 50-50 chance that the offspring will suffer from amyotrophic lateral sclerosis if one of the parents has the disease.
2. Age: the disease is more common between 40 and 60 years.
3. Gender: the incidence of the disease is more in males before 65 years of age however no such difference exists after 65 years
4. Smoking increases the risk of suffering from amyotrophic lateral sclerosis
5. Lead exposure especially at workplace is another important risk factor
6. Being in military services increases the risk although the exact cause is not known. However exposure to certain chemicals, viral infections, excessive stress, injury etc might be the possible causes.

Treatment
There is no cure for the disease. The aim of treatment is to slow the progression of the disease, prevention of complications and making life a little bit comfortable and normal to some extent.

The only drug approved by FDA for amyotrophic lateral sclerosis is riluzole; it acts by reducing the level of glutamate in the nervous system. Other drugs are prescribed to relieve certain symptoms namely muscle cramps, spasticity, pain, excessive saliva production, insomnia etc.

Breathing support, speech therapy, physical therapy, nutritional support become essential as the disease progresses. Psychological help is also required for the both the patient and the family members.