Amyotrophic Lateral Sclerosis (Lou Gehrig's Disease)

--A rapidly progressive, degenerative disease of the upper and lower motor neurons characterized by atrophy of the hands, arms, legs, and, eventually, the entire body. Seventy percent of individuals die within 5 years of diagnosis.
 
Causes and Incidence
The etiology of amyotrophic lateral sclerosis (ALS) is unknown, but proposed explanations include genetics, metabolic disturbances, and external agents. Although the incidence worldwide is 60 to 70 people per 100,000, with large clusters of cases in the western Pacific, the incidence in the United States is only about 5 in 100,000. The disease usually occurs in men between 40 and 70 years of age.
 
Disease Process
Patterns of degeneration occur in the brain and spinal cord. The anterior horn cells deteriorate, resulting in denervation of muscle fibers. Atrophy of the precentral gyrus and loss of Betz's cells occur in the cortex. Motor neurons are lost in the brainstem, although neurons that control the sensory and urinary sphincters are spared. The corticospinal tract and large motor neurons in the spinal cord also atrophy.
 

Symptoms 
 
Early
Weakness, cramps in the hands and forearms
 
Midcourse     
Fatigue; dyspnea; slurred speech; dysphagia; asymmetric spread of muscle weakness to the rest of the body; spasticity; fasciculations; hyperactive deep tendon and extensor plantar reflexes
 
Late 
Paralysis of vocal cords; paralysis of chest muscles, necessitating ventilatory support
 
Potential Complications 

The end stage of ALS can be complicated by disuse syndrome, contractures, skin breakdown, and aspiration pneumonia.
 

Diagnostic Tests 
 
Clinical evaluation  
Any of the above manifestations; motor involvement unaccompanied by sensory abnormalities
 
Electromyography
Fibrillation, positive waves, fasciculations, giant motor units
 
Blood
Possible elevation in creatinine phosphokinase
 
Spinal tap
Elevated total protein; normal cell and IgG concentrations
 
Computed tomography scan
Normal until cerebral atrophy  late in disease
 
Myelogram
Normal; spinal cord atrophy late in disease
 

Treatments 
 
Surgery  
Cricopharyngeal myotomy to alleviate dysphagia; tracheostomy; esophagostomy/ gastrostomy
 
Drugs   
Muscle relaxants (e.g., baclofen) to control spasticity; tricyclic antidepressants to control saliva; phenytoin to reduce cramping
 
General            
Physical therapy to maintain muscle strength; occupational therapy for activity of daily living support; speech therapy to aid communication; splints for neutral joint alignment; leg braces, canes, walkers to aid ambulation; nutritional support/tube feedings; cardiac monitoring; mechanical ventilation; counseling for individual and family; respite care or placement if family is unable to provide care.