Amyotrophic lateral sclerosis


Amyotrophic lateral sclerosis, or ALS, is a disease of the nerve cells in the brain and spinal cord that control voluntary muscle movement.ALS is also known as Lou Gehrig's disease.

Alternative Names

Lou Gehrig's disease; ALS; Upper and lower motor neuron disease; Motor neuron disease

Causes, incidence, and risk factors

1 out of 10 cases of ALS are due to a genetic defect. The other times, the cause is unknown.In ALS, nerve cells (neurons) waste away or die, and can no longer send messages to muscles. This eventually leads to muscle weakening, twitching, and an inability to move the arms, legs, and body. The condition slowly gets worse. When the muscles in the chest area stop working, it becomes hard or impossible to breathe.ALS affects approximately 5 out of every 100,000 people worldwide.There are no known risk factors, except for having a family member who has a hereditary form of the disease.


Symptoms usually do not develop until after age 50, but they can start in younger people. Persons with ALS have a loss of muscle strength and coordination that eventually gets worse and makes it impossible to do routine tasks such as going up steps, getting out of a chair, or swallowing.Breathing or swallowing muscles may be the first muscles affected. As the disease gets worse, more muscle groups develop problems.ALS does not affect the senses (sight, smell, taste, hearing, touch). It only rarely affects bladder or bowel function, eye movement, or a person's ability to think or reason.Symptoms include:Difficulty breathingDifficulty swallowing Choking easilyDroolingGaggingHead drop due to weakness of the neck musclesMuscle crampsMuscle contractions called fasciculationsMuscle weakness that slowly gets worse Commonly involves one part of the body first, such as the arm or handEventually leads to difficulty lifting, climbing stairs, and walkingParalysisSpeech problems, such as a slow or abnormal speech pattern (slurring of words)Voice changes, hoarsenessWeight loss

Signs and tests

The doctor or nurse will examine you and ask questions about your medical history and symptoms.The physical exam may show: Weakness, often beginning in one areaMuscle tremors, spasms, twitching, or loss of muscle tissue Twitching of the tongue (common)Abnormal reflexesStiff or clumsy walkIncreased reflexes at the jointsDifficulty controlling crying or laughing (sometimes called emotional incontinence)Loss of gag reflexTests that may be done include:Blood tests to rule out other conditionsBreathing test to see if lung muscles are affectedCervical spine CT or MRI to be sure there is no disease or injury to the neck, which can mimic ALSElectromyography to see which nerves or muscles do not work properlyGenetic testing, if there is a family history of ALSHead CT or MRI to rule out other conditionsSwallowing studiesSpinal tap (lumbar puncture)


There is no known cure for ALS. A medicine called riluzole helps slow down the symptoms and lets you live longer. Treatments to control other symptoms include:Baclofen or diazepam for spasticity that interferes with daily activitiesTrihexyphenidyl or amitriptyline for people with problems swallowing their own salivaPhysical therapy, rehabilitation, use of braces or a wheelchair, or other measures may be needed to help with muscle function and general health.Choking is common. Patients may decide to have a tube placed into their stomach for feeding. This is called a gastrostomy.A nutritionist is very important. Patients with ALS tend to lose weight. The illness itself increases the need for food and calories. At the same time, problems with swallowing make it hard to eat enough.Breathing devices include machines that are used only at night, and constant mechanical ventilation.Patients should discuss their wishes regarding artificial ventilation with their families and doctors.

Support Groups

Emotional support is vital in coping with the disorder, because mental functioning is not affected. Groups such as the ALS Association may be available to help people who are coping with the disorder.Support for people who are caring for someone with ALS is also available, and may be very helpful.See: ALS - support group

Expectations (prognosis)

Over time, people with ALS progressively lose the ability to function and care for themselves. Death often occurs within 3 - 5 years of diagnosis. About 1 in 4 patients survive for more than 5 years after diagnosis.


Breathing in food or fluid (aspiration)Loss of ability to care for selfLung failure (See: Adult respiratory distress syndrome)PneumoniaPressure soresWeight loss

Calling your health care provider

Call your health care provider if:You have symptoms of ALS, particularly if you have a family history of the disorderYou or someone else has been diagnosed with ALS and symptoms get worse or new symptoms developIncreased difficulty swallowing, difficulty breathing, and episodes of apnea are symptoms that require immediate attention.


You may want to see a genetic counselor if you have a family history of ALS.


Murray B, Mitsumoto H. Disorders of upper and lower motor neurons. In: Daroff RB, Fenichel GM, Jankovic J, eds. Bradley’s Neurology in Clinical Practice. 6th ed. Philadelphia, Pa: Saunders Elsevier; 2012:chap 74.Shaw PJ. Amyotrophic lateral sclerosis and other motor neuron diseases. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 418.

Review Date: 8/26/2012
Reviewed By: Luc Jasmin, MD, PhD, Department of Neurosurgery at Cedars-Sinai Medical Center, Los Angeles, and Department of Anatomy at UCSF, San Francisco, CA. Review provided by VeriMed Healthcare Network. David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.
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