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amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis, also known as ALS, "Lou Gehrig's disease," or Motor Systems Disease, is a progressive condition of the nervous system.

Nerve cells known as motor neurons are located in the spinal cord and brain and normally give signals to muscles. ALS causes these neurons to degenerate, or break down.

When the motor neurons stop sending signals to muscles, the muscles atrophy, meaning that they weaken and shrink. This may progress to paralysis. Spasticity, an increase in the muscle tone that makes it hard to coordinate movement, may also develop as a result of ALS.

What is going on in the body?

The muscle weakness in ALS can affect the muscles of the limbs or of the tongue, mouth, and throat. The nerves that connect the brain and spinal cord, called motor neurons, can also degenerate.

What are the signs and symptoms of the disease?

Weakness often starts in one arm or leg and progresses to the other limbs. Muscles may atrophy or have cramps or twitches. Hands, arms, and legs can become clumsy and stiff. The person may have trouble swallowing, and speech may be slurred.

Ultimately, the muscles involved in breathing weaken and eventually stop working. ALS does not usually affect bowel and bladder control.

What are the causes and risks of the disease?

Cases that run in families are rare and result from a defect on one of the chromosomes, the structures in the cells that hold genetic information. In most cases the cause of ALS is not known.

What can be done to prevent the disease?

There is no known way to prevent ALS.

How is the disease diagnosed?

A neurological exam and a clinical history are most important

One test that is used in conjunction with the history and physical is electromyography (EMG). A nerve conduction test usually accompanies the EMG and helps to clarify the diagnosis.

Other diseases that mimic ALS, such as Guillain-Barré syndrome (GBS), cervical spinal stenosis, or lumbar stenosis, must be ruled out. A spinal tap is usually done to rule out other more rare conditions that mimic ALS.

What are the long-term effects of the disease?

ALS is progressive and usually results in death in about three to five years from the time of symptom onset, due to paralysis of the respiratory muscles.

What are the risks to others?

Genetic counseling is advised in the inherited forms of the disease.

What are the treatments for the disease?

There is no effective treatment for ALS. The drug riluzole (i.e., Rilutek) may add 3 months to life expectancy. Creatine may help improve strength. Physical, occupational, and speech therapy are helpful. Baclofen (i.e., Kemstro), tizanidine (i.e., Zanaflex), and diazepam (i.e., Valium) may help to relax spastic muscles.

Feeding tubes are often needed in the end stages of the disease. A ventilator - an artificial breathing machine - can be used to prolong the life of someone with ALS. However, the poor quality of life and the risks of pneumonia and other complications with long-term dependence on a ventilator have dissuaded most people with ALS from using one.

What are the side effects of the treatments?

There are very few side effects from the medicines used for people with ALS. Sedation is probably the most common side effect.

What happens after treatment for the disease?

Treatment usually does not extend life. It can ease pain or discomfort and spasticity and help with general care.

How is the disease monitored?

The disease is monitored by a healthcare professional on a routine basis. Pulmonary function tests may be used to monitor weakness of muscles used for breathing. Any new or worsening symptoms should be reported to the healthcare professional.