Alternative Names Lou Gehrig's disease, progressive bulbar palsy, ALS, motor neurone disease (MND)
Definition Amyotrophic lateral sclerosis (ALS) is a progressive disease of the nervous system. The nerve cells, or neurons, that are located in the spinal cord and brain degenerate, or break down. The affected nerves in ALS normally give signals to muscles, so their break down causes muscles to weaken and atrophy, or shrink. Paralysis or spasticity, which is increased muscle tone that can make co-ordinated movement difficult, may also develop. There is no damage to the sensory neurones, thus there is no sensory disturbance.
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, or motor neurons, that connect the brain and spinal cord 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. Bowel and bladder control are usually not affected until late in the course of the disease.
What are the causes and risks of the disease? Cases that run in families are often due to a defect on one of the chromosomes, the structures that hold genetic information. Otherwise 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? The diagnosis is based on special tests known as electromyography (EMG) and nerve conduction (NCV) studies, as well as a neurological examination and a clinical history. Other diseases that mimic ALS, such as conditions known as cervical spinal or lumbar stenosis, must be ruled out.
What are the long-term effects of the disease? ALS is usually progressive. Half of people with ALS die within 3 years, and 90% die within 6 years.
What are the risks to others? Genetic counselling 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 may add 3 months to life expectancy. Creatine may help improve strength. Physio, occupational, and speech therapy are helpful. Baclofen, and diazepam may help to relax spastic muscles. Feeding tubes are often needed in the end stages of the disease. A ventilator, or breathing machine, can be used to prolong the life of someone with ALS. However, most people with ALS do not request a ventilator to prolong their lives.
What are the side effects of the treatments? There are very few side effects from the medications 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 doctors and specialists.
Author: Michael Curiel, MD Reviewer: HealthAnswers Australia Medical Review Panel Editor: Dr David Taylor, Chief Medical Officer HealthAnswers Australia Last Updated: 1/10/2001 Contributors Potential conflict of interest information for reviewers available on request
