Amyotrophic lateral sclerosis (ALS)
Amyotrophic lateral sclerosis (ALS), sometimes called Lou Gehrig’s disease, is a rapidly progressive, fatal neurological disease that attacks the nerve cells (neurons) responsible for controlling voluntary muscles. The disease belongs to a group of disorders known as motor neuron diseases, characterized by the gradual breakdown and death of motor neurons, which makes it impossible for them to send messages to muscles. Unable to function, the muscles gradually weaken and waste away. Eventually, the ability of the brain to start and control voluntary movement is lost.
ALS causes weakness with a broad range of disabilities. Eventually, all muscles under voluntary control are affected, and patients lose their strength and the ability to move their arms, legs and body. When muscles in the diaphragm and chest wall fail, patients lose the ability to breathe without the support of a ventilator. Most people with ALS die from respiratory failure, usually within 3 to 5 years from the onset of symptoms. However, about 10 percent of ALS patients survive for 10 or more years.
ALS does not affect a person's ability to see, smell, taste, hear or recognize touch. Patients usually maintain control of eye muscles and bladder and bowel functions, although in the late stages of the disease most patients will need help getting to and from the bathroom.
ALS affects approximately five out of every 100,000 people worldwide. In 90 to 95 percent of all ALS cases, the disease occurs apparently at random with no clearly associated risk factors. Patients do not have a family history of the disease, and their family members are not considered to be at increased risk for developing ALS. About 5 to 10 percent of all ALS cases are considered inherited.
The onset of ALS may be so subtle that symptoms are overlooked.
- Stiffness of muscles
- Muscle weakness affecting an arm or a leg
- Slurred and nasal speech
- Difficulty chewing or swallowing
- Awkwardness when walking or running
- Tripping and stumbling more often than usual
- Difficulty with tasks that require manual dexterity, such as writing
- Increasing problems with movement
- Difficulty swallowing and speaking
- Tight and stiff muscles (spasticity)
- Exaggerated reflexes, including an overactive gag reflex
- Progressive muscle weakness and atrophy
- Muscle cramps and twitching
- Difficulty standing
Because the disease usually does not affect cognitive abilities, patients are aware of their progressive loss of function and may become anxious and depressed. A small percentage of patients may experience problems with memory or decision-making, and growing evidence suggests that some may even develop a form of dementia.
No single test can provide a definitive diagnosis of ALS, although the presence of upper and lower motor neuron signs in a single limb is a strong suggestion of the disorder. The diagnosis of ALS is primarily based on the symptoms and signs the doctor observes in the patient and a series of tests to rule out other diseases.
Doctors begin the process with a full medical history and usually conduct a neurologic examination at regular intervals to assess whether symptoms such as muscle weakness, atrophy of muscles, hyperreflexia and spasticity are getting progressively worse.
Because symptoms of ALS can be similar to those of a variety of other, more treatable diseases or disorders, appropriate tests must be conducted to exclude the possibility of other conditions. These include:
- Electromyography (EMG)
- Nerve conduction studies (NCS)
- MRI to rule out other conditions, such as tumor or herniated disc
- Routine laboratory tests
- Muscle biopsy
No cure has yet been found for ALS. However, the Food and Drug Administration (FDA) has approved the first drug treatment for the disease – riluzole (Rilutek). Riluzole is believed to reduce damage to motor neurons by decreasing the release of glutamate. Clinical trials with ALS patients showed that riluzole prolongs survival by several months, mainly in those with difficulty swallowing. The drug also extends the time before a patient needs ventilation support.
Riluzole does not reverse the damage already done to motor neurons, and patients taking the drug must be monitored for liver damage and other possible side effects. However, this first disease-specific therapy offers hope that the progression of ALS may one day be slowed by new medications or combinations of drugs.
Other treatments for ALS are designed to relieve symptoms and improve the quality of life for patients. They include:
- Supportive care by a multidisciplinary team of healthcare professionals
- An individualized plan of medical care and physical therapy
- Medications to reduce fatigue, ease muscle cramps and control spasticity and other symptoms
- Antidepressants and sleep medications
- Physical therapy and special equipment to enhance independence
- Low-impact aerobic exercises such as walking, swimming and stationary bicycling
- Range-of-motion and stretching exercises
- Speech therapy
- Nutrition counseling
- Ventilator support when muscles that assist in breathing weaken
- Social workers, home care and hospice nurses to help with the medical, emotional and financial challenges of coping with ALS
Source: National Institute of Neurological Disorders and Stroke
For More Information
National Institute of Neurological Disorders and Stroke
Les Turner ALS Foundation