Amyotrophic lateral sclerosis (ALS) - Lou Gehrig's disease
Amyotrophic lateral sclerosis (ALS) was first described in 1869. It is frequently referred to as "Lou Gehrig's disease" in memory of the famous baseball player who died of ALS in 1941. ALS is defined as adult-onset, idiopathic, progressive degeneration of anterior horn cells and upper and lower motor neurons resulting in progressive muscle weakness, wasting and fasciculations. The clinical picture varies, depending on the location and progression of the pathologic changes. Diagnostic criteria of the World Federation of Neurology can help define and classify ALS. Amyotrophic lateral sclerosis (ALS) - widely known as Lou Gehrig's disease - causes degeneration of the nerve cells in certain regions of the brain and spinal cord that control your voluntary muscles. Eventually, you lose your ability to move your limbs and the muscles you need to breathe.
The causes of the disease remain elusive. Although there's no reversing the progression of ALS, advances in treatment have meant that many who have the disease are living longer.
Signs and symptoms
ALS commonly begins in one part of your body and progresses slowly. Gradual death of nerve cells saps muscles of their control. Early signs and symptoms of ALS include:
The disease typically begins in the hands, feet and limbs, then spreads to the trunk. It eventually affects bulbar functions such as chewing, swallowing, speaking and breathing. Less commonly, ALS begins with these bulbar symptoms. As the disease advances, your muscles become progressively weaker until they're paralyzed. ALS usually leaves your intellect intact and spares your senses of sight, hearing, smell, taste and touch.
Eventually, ALS paralyzes the muscles you use to breathe. Most people with ALS die of respiratory failure. Sometimes, people with ALS stop breathing because they aspirate food and oral secretions that they can't swallow.
The basic units of your central nervous system (brain and spinal cord) are nerve cells (neurons). These cells communicate with one another and send and receive signals throughout your body. Each neuron consists of a cell body, a major branching fiber (axon) and numerous smaller branching fibers (dendrites). Nerve cells communicate with adjacent nerve cells at contact points called synapses.
Nerve signals provide information to your brain through your senses, they communicate with your involuntary muscles — the ones that control activities such as digestion, sexual function and heartbeat — and they activate your voluntary muscles, through your peripheral nervous system.
ALS is a disease that involves death of motor neurons — nerve cells that control voluntary muscles. These are the muscles you use to move your limbs, face, neck and torso and to talk, chew, swallow and breathe. In ALS, both upper motor neurons, located in your brain, and lower motor neurons, located in your spinal cord, gradually die. Over time, this results in your voluntary muscles no longer receiving messages. Your muscles become weak and begin to waste away (atrophy).
ALS occurs in two forms:
Researchers aren't sure what causes ALS. One possible cause is excess glutamate, which is one of the many chemicals (neurotransmitters) that neurons use to send signals to one another. Too much glutamate can cause neurons to die. People with ALS appear to have too much glutamate in their nervous system.
Although most cases of ALS occur from no apparent cause, about 5 percent to 10 percent of people who have ALS inherit it. Inherited ALS may strike at a younger age and in consecutive generations. If you're the first person in your family to have ALS, you likely don't have an inherited form, and your children aren't at a greater risk.
Noninherited ALS often develops between ages 40 and 60, although the disease affects people of all ages. Men are somewhat more frequently affected than women are.
When to seek medical advice
If you've noticed slow, progressive weakness in one of your limbs, accompanied by twitching and cramping of the affected muscles, see your doctor to determine if there may be a neurologic cause such as ALS. Although there's no treatment to reverse the course of ALS, other neurologic conditions that may mimic some of the signs and symptoms of ALS are treatable. The sooner you see your doctor, the sooner a diagnosis and treatment decisions can be made.
Screening and diagnosis
ALS is difficult to diagnose early because it may appear similar to other neurologic diseases. Your doctor may refer you to a specialist in nerve disorders (neurologist) if you have signs and symptoms of a neurologic condition.
Diagnosing ALS first involves reviewing your family's medical history and your signs and symptoms. You'll then have a physical examination that may include some basic in-office testing of your nerves and muscles. Additionally, you'll undergo a variety of tests, including tests to rule out other conditions. These diagnostic tests may include:
Because there's no reversing the course of ALS, treatments mainly involve efforts to make you more comfortable and independent and to slow the progression of symptoms. Treatments may involve many professionals, including doctors, therapists, nutritionists, social workers and hospice nurses, and may include:
Having ALS greatly changes your lifestyle and that of your family and creates a high financial burden. Fortunately, you can share your concerns in a support group with others who have ALS and their family members.