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Amyotrophic Lateral Sclerosis by Rosalyn Carson-DeWitt, MD

Definition

Amyotrophic lateral sclerosis (ALS) is a progressive nervous system disorder. It gradually destroys the nerves responsible for muscle movement. Over time, ALS leads to almost total paralysis of muscle movement, including breathing.

Prognosis is poor in most cases because of the progressive nature of the condition. Eventually, the disorder leads to respiratory failure. After diagnosis, life span ranges from 2 to 5 years. The five-year survival rate ranges from 14% to 25%. Up to 10% of patients will survive more than 10 years. In general, the younger the age of onset, the slower the disease progresses.

The Nervous System

Causes

The cause of ALS is unknown. In a small number of cases, it appears that genes may play a role. Also, research has shown that there may be a reduced response to cell stress and cell toxicity. The reduced response may be due to a build-up of certain protein in the brain.

Risk Factors

A risk factor is something that increases your chance of getting a disease or condition. Risk factors include:

Having a family member with ALS
Being in the military or having other occupations with risk of exposure
Having certain genetic mutations

Symptoms

Symptoms of ALS include:

Progressive weakness in arms and legs (at first often on only one side) over weeks to months without changes in sensory abilities.
Initial presentation may be a wrist or foot drop
Trouble holding things without dropping them
Frequent tripping while walking
Shrunken muscles
Twitchy muscles
Unpredictable changing emotions
Clumsiness
Overactive reflexes
Slurred speech
Hoarseness
Trouble chewing and swallowing, resulting in frequent choking and gagging
Weight loss due to trouble eating
Trouble breathing
Excess salivation, drooling
Mental skills and abilities remain unchanged in most
Sensation is intact
Trouble coughing, resulting in development of pneumonia

Diagnosis

The doctor will ask about your symptoms and medical history and perform a physical exam. There are no tests that definitively diagnose ALS.

Tests may be used to rule out other medical conditions. These tests may include:

Electromyogram (EMG)/nerve conduction velocities (NCV)—To evaluate the muscles and the nerves
Computed tomography (CT) Scan—A type of x-ray that uses a computer to make pictures of the structures inside the head and spine
Magnetic Resonance Imaging (MRI) Scan—A test that uses magnetic waves to make pictures of the structures inside the head and spine
Blood tests—To rule out metabolic, heavy metal exposure, or rarely infections (e.g., Lyme disease, HIV, human T-lymphotropic virus [HTLV])
Lumbar puncture—A procedure to collect cerebrospinal fluid (CSF)
Urine tests

Treatment

There is currently no cure for ALS.

Some treatment may help to reduce or manage symptoms for a time. For you and your family, a multidisciplinary approach may work best. This approach may include:

Taking medicines
Working with therapists and joining a support group
Participating in religious and social activities

Treatment options include:

Medications

The drug riluzole has been approved for ALS. Clinical trials reveal a modest lengthening of survival. The drug may slightly improve functioning, but it does not stop the disease from progressing. Other drugs are also being studied.

Your doctor may prescribe these medicines for symptoms:

Diazepam (e.g., Valium), baclofen (e.g., Lioresal), or dantrolene—To reduce spasticity
Nonsteroidal anti-inflammatory drugs (NSAIDs) and other pain medicines
Atropine (e.g., AtroPen), scopolamine (e.g., Isopto), botulinum toxin (e.g., Botox), antihistamine—To reduce heavy drooling
Antidepressants and anti-anxiety medicines
A combination of dextromethorphan and quinidine—To treat inappropriate laughter or crying

Other Types of Treatments

Supportive care may be needed as ALS progresses including:

Physical therapy—To reduce pain associated with muscle cramping and spasticity.
Respiratory care—In some cases, you may need to receive a mixture of air and oxygen from a machine. If you cannot move enough air in and out of your lungs, you may need surgery to have a tube inserted into your airway.
Nutritional care—Your doctor may make changes to your diet. In some cases, getting nutrition through tube feeding is needed.
Speech therapy—Speech therapy may be used to optimize communication. Therapy can include exploring alternative methods of communication.

Prevention

There are no guidelines for preventing ALS because the cause is unknown.

RESOURCES:

ALS Association http://www.alsa.org/
National Institute of Neurological Disorders and Stroke http://www.ninds.nih.gov/

CANADIAN RESOURCES:

ALS Society of British Columbia http://www.alsbc.ca/
ALS Society of Canada http://www.als.ca/

References:

Aggarwal, SP, Zinman L, Simpson E, et al. Clinical trial testing lithium in ALS terminates early for futility. Lancet Neurol. 2010; 9(5): 481-488.
Amyotrophic lateral sclerosis. EBSCO DynaMed website. Available at: https://dynamed.ebscohost.com/. Updated January 11, 2012. Accessed September 8, 2012.
Amyotrophic lateral sclerosis fact sheet. National Institute of Neurological Disorders and Stroke website. Available at: http://www.ninds.nih.gov/disorders/amyotrophiclateralsclerosis/detail_amyotrophiclateralsclerosis.htm. Accessed September 8, 2012.
Bradley WG, Daroff RB. Neurology In Clinical Practice. Philadelphia, PA: Butterworth Heinemann Publishing; 2004.
Kasper DL, Braunwald E, Fauci AS, et al. Harrison's Principles of Internal Medicine. 16th ed. New York, NY: The McGraw-Hill Companies; 2005.
Miller RG, Mitchell JD, Lyon M, et al. Riluzole for amyotrophic lateral sclerosis (ALS)/motor neuron disease (MND). The Cochrane Library. Chichester, England: John Wiley & Sons, Ltd; 2005.
Samuels MA, Feske SK. Office Practice of Neurology. Philadelphia, PA: Churchill Livingstone; 2003.
Sathasivam S. Managing patients with amyotrophic lateral sclerosis. Eur J Intern Med. 2009;24:355-358.
Walling AD. Amyotrophic lateral sclerosis: Lou Gehrig's disease. Am Fam Physician. 1999;59:1489-1496.
4/17/2008 DynaMed Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance: Fornai F, Longone P, Cafaro L, et al. Lithium delays progression of amyotrophic lateral sclerosis. Proc Natl Acad Sci USA. 2008;105:2052-2057.
1/14/2011 DynaMed's Systematic Literature Surveillance DynaMed's Systematic Literature Surveillance: Mateen FJ, Carone M, Sorenson EJ. Patients who survive 5 years or more with ALS in Olmsted County, 1925-2004. J Neurol Neurosurg Psychiatry. 2010;81(10):1144-1146.

Last reviewed October 2012 by Rimas Lukas, MD

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