Amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, is a progressive degeneration of nerve cells that control muscle movements. The disease, the most common motor neuron disease among adults, became known as Lou Gehrig's disease after the New York Yankee's Hall of Fame first baseman. Gehrig's career ended in 1939 because of the condition. About 30,000 patients in this country have the disease and about 5,000 are diagnosed with ALS every year.

ALS tends to strike in mid-life between the ages of 40 and 60, but others can develop the disease. Men are about one-and-a-half times more likely to have the disease than women. In most cases, it occurs at random with no family history of the disease.

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ALS attacks nerve cells and pathways in the brain and spinal cord, causing the body's motor neurons to waste away. The result is progressive muscle weakness and in coordination, causing difficulty with mobility, speaking, swallowing and breathing.

Proper medication and physical therapy, however, can help control symptoms and allow patients to lead more independent lives.

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At first, symptoms of ALS may be barely noticed. But over time, the disease worsens. As nerve cells die, the muscles they control stop acting and reacting correctly.

  • Arms and legs may lose strength and coordination.
  • Feet and ankles may become weak.
  • General fatigue may develop
  • Muscles in the arms, shoulders and tongue may cramp or twitch.
  • Swallowing, speaking and breathing may become difficult.

Eventually, ALS weakens muscles, including muscles used for breathing, until they become paralyzed. Unable to swallow, patients with ALS may aspirate or inhale food or saliva into their lungs. In fact, most people with ALS die of respiratory failure. The ability to think, see, hear, smell, taste and touch, however, usually is not affected.

ALS can be very difficult to diagnose. There is no one test or procedure to confirm the diagnosis.

To determine if you have ALS, your doctor will perform an evaluation that includes a physical exam, medical history, lab tests such as blood and urine tests, and imaging tests such as magnetic resonance imaging (MRI) of the brain and spinal cord.

Electromyography (EMG) may be used to test the health of your muscles and the nerves controlling your muscles. This test is very sensitive in detecting lower motor neuron disease.

There are no standard laboratory tests for upper motor neuron disease. But certain signs may be interpreted by your doctor as signs of ALS such as:

  • Babinski's reflex, an unusual flexing of the toes that signals damaged nerve paths
  • Diminished fine motor coordination
  • Muscle cramps, which can be painful, and twitching
  • Spasticity, a specific type of stiffness that causes jerky, hard to control movements

Although there is no known cure for ALS, the drug riluzole has been approved for treatment and may slow progression of the disease. It is expensive, however, and appears modestly effective. Generally, treatment is designed to help control symptoms.

Medications prescribed include

  • Drugs such as baclofen or diazepam may help control spasticity.
  • Gabapentin may be prescribed to help control pain.
  • Trihexyphenidyl or amitriptyline may help patients swallow saliva.

Because choking is common as ALS progresses, patients may need a tube called a percutaneous endoscopic gastrostomy (PEG) tube or feeding tube to be placed into the stomach for feeding. A referral to an otolaryngologist — an ear, nose and throat specialist — may be recommended.

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Reviewed by health care specialists at UCSF Medical Center.