Lou Gehrig's Disease (Amyotrophic Lateral Sclerosis)

Lou Gehrig's disease, or amyotrophic lateral sclerosis (a-my-o-TROF-ik LATer-al skle-RO-sis) (ALS), is a rare disease. It is hereditary in some cases, but in most cases, its cause is unknown. ALS is not an infectious disease, meaning people cannot catch it from someone who has it. ALS affects the body's neurons, or nerve cells, that control movement of the voluntary (skeletal) muscles.

Lou Gehrig's disease or amyotrophic lateral sclerosis (ALS) is a progressive and fatal neurological disease that attacks the nerve cells (neurons) responsible for controlling voluntary muscles (such as those in the arms, legs, and face). It belongs to a group of disorders known as motor neuron diseases, which are characterized by the gradual degeneration and death of motor neurons.

There are many different types of ALS, differentiated by their signs, symptoms, and genetic association. Sporadic ALS is the most common form of ALS, and occurs in people with no apparent history of the disorder in their family. Family members of a person with sporadic ALS are not considered to be at an increased risk for developing the disease. Symptoms of sporadic ALS usually first develop in a person's late 50s or early 60s. Less common is familial ALS, meaning there is a family history of ALS or a related condition called frontotemporal dementia (FTD), which is a progressive brain disorder that affects personality, behavior, and language. The familial form of ALS is usually inherited; it only requires one parent to carry the gene responsible for the disease. The signs and symptoms of familial ALS typically first appear in a person's late 40s or early 50s. Rarely, people with familial ALS develop symptoms in childhood or their teenage years. It a rare form of the disorder known as juvenile ALS.

Lou Gehrig's disease 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. In late stages of the disease most people with ALS need help getting to and from the bathroom.

Lou Gehrig's disease is one of the most common neuromuscular diseases worldwide. As of 2016, more than 12,000 people in the United States had a diagnosis of ALS. It affects people of all races and ethnic backgrounds. The disease is more common among white males, non-Hispanics, and persons aged 60 to 69 years, but younger and older people can also develop the disease. Men are affected more often than women. Sporadic ALS accounts for 90 to 95 percent of all ALS cases. About 5 to 10 percent of all ALS cases are inherited.

A variant of ALS, known as Western Pacific ALS, had a particularly elevated incidence among people on the Pacific island of Guam in the 1950s and 1960s. The rate later declined, and researchers believe that an undetermined environmental factor may have been the cause.

ALS affects the upper and lower motor neurons * in the body. The upper motor neurons are located in the cerebral cortex * of the brain and send signals for muscle movement to the spinal cord, where the lower motor neurons then carry the signals to the muscles. Damage to the upper motor neurons results in such symptoms as heightened gag reflex or other reflexes, and stiff muscles. Damage to the lower motor neurons includes muscle weakness, cramps, and twitches. In ALS, both upper and lower motor neurons degenerate or die. In either case, they no longer function. For this reason, symptoms of both upper and lower motor neuron damage are part of the diagnosis of ALS.

Typically, the disease produces weakness and paralysis * in the muscles it affects, and it causes these muscles to waste away. About 40 percent of people with ALS first notice very minor symptoms, such as clumsiness in their hands when they try to perform such routine tasks as buttoning a shirt. Others may feel weakness in their legs or notice that their speech has become slower.

People usually die within a few years after they develop ALS. In a very few cases, symptoms may stabilize at some point, remaining the same for years without getting any worse.

Physicians can distinguish ALS from other diseases of the nervous system by its usually late onset in life and by the progressive nature (worsening of symptoms) of the illness. The fact that the sense of touch is not affected also helps in diagnosis. Like ALS, multiple sclerosis (MS), a more common disease, affects the nervous system. Unlike ALS, however, MS attacks the nervous system in a number of different ways rather than involving only the motor nerves.

Physicians perform different kinds of medical tests to diagnose ALS. Tests may include the following:

As of 2016, Lou Gehrig's disease had no known cure, but a few medications can ease the muscle spasms and possibly even slow the rate at which symptoms get worse. People who have ALS maintain an independent lifestyle as much as possible by taking different measures. Physical therapy, such as massage and regulated exercises, can reduce disability somewhat by helping the muscles to work better. Such aids as canes, walkers, and wheelchairs can help people with ALS remain independent. Mechanical ventilation (machine-assisted breathing support) is often needed in the later stages of the disease.

French neurologist Jean-Martin Charcot (1825–1893) was the first to describe ALS and gave the disease its name.

Charcot noted in detail the wasting of muscles (amyotrophy) and the hardening (sclerosis) of motor nerves along the sides (laterally) of the spinal cord. In France, ALS is known as la maladie de Charcot (meaning “Charcot's disease”) and in Great Britain it is called motor neurone disease.

See also Multiple Sclerosis (MS) • Paralysis

* neurons are nerve cells. Most neurons have extensions called axons and dendrites through which they send and receive signals from other neurons.

* cerebral cortex (suh-REE-brul KOR-teks) is the part of the brain that controls functions such as conscious thought, listening, and speaking.

* paralysis (pah-RAH-luh-sis) is the loss or impairment of the ability to move some part of the body.