Amyotrophic lateral sclerosis

Commonly called Lou Gehrig disease, after the New York Yankee first baseman who died of this disorder, amyotrophic lateral sclerosis (ALS) is the most common motor neuron disease causing muscular atrophy. Other motor neuron diseases include progressive muscular atrophy and progressive bulbar palsy. Onset occurs between ages 40 and 70. A chronic, progressively debilitating disease, ALS is rapidly fatal.

Causes
The disease is progressive, with death resulting from respiratory paralysis (the median survival is 3 to 5 years), and it’s three times more common in men than in women. The exact cause of ALS is unknown, but 5% to 10% of ALS cases have a genetic component. In these cases, it’s an autosomal dominant trait that affects men and women equally.

ALS and other motor neuron diseases may result from:

• a slow-acting virus
• nutritional deficiency related to a disturbance in enzyme metabolism
• metabolic interference in nucleic acid production by the nerve fibers
• an autoimmune disorder that affects immune complexes in the renal glomerulus and basement membrane.

Precipitating factors for acute deterioration include trauma, viral infections, and physical exhaustion.

Signs and symptoms
Patients with ALS develop fasciculations, accompanied by atrophy and weakness, especially in the muscles of the forearms and the hands. Other signs include impaired speech; difficulty chewing, swallowing, and breathing, particularly if the brain stem is affected; and, occasionally, choking and excessive drooling.
Mental deterioration doesn’t usually occur, but patients may become depressed as a result of the disease. Progressive bulbar palsy may cause crying spells or inappropriate laughter.

Diagnosis
Characteristic features indicate a combination of upper and lower motor neuron involvement without sensory impairment. Electromyography and a muscle biopsy help show nerve, rather than muscle, disease. The protein content of cerebrospinal fluid is increased in one-third of patients, but this finding alone doesn’t confirm ALS.
Diagnosis must rule out multiple sclerosis, spinal cord neoplasm, polyarteritis, syringomyelia, myasthenia gravis, and progressive muscular dystrophy.

Treatment
Management aims to control symptoms and provide emotional, psychological, and physical support.

Special considerations

• Care begins with a complete neurologic assessment—a baseline for future evaluations of progressing disease.
• Implement a rehabilitation program designed to help the patient maintain independence for as long as possible.
• Help the patient obtain equipment, such as a walker and a wheelchair. Arrange for a visiting nurse to monitor the patient’s status, to provide support, and to teach the family about the illness.
• Depending on the patient’s muscular capacity, assist with bathing, personal hygiene, and transfers from wheelchair to bed. Help the patient establish a regular bowel and bladder routine.
• To help the patient handle increased accumulation of secretions and dysphagia, teach him to suction himself. He should have a suctioning machine handy at home to prevent aspiration and to reduce his fear of choking. The family should also be taught which signs and symptoms of aspiration pneumonia are important to report (fever, increased respiratory rate, increased or colored secretions, difficulty breathing).
• To prevent skin breakdown, provide good skin care when the patient is bedridden. Turn him often, keep his skin clean and dry, and use sheepskins or pressure-relieving devices.
• If the patient has trouble swallowing, give him soft, solid foods and position him upright during meals. Gastrostomy and nasogastric tube feedings may be necessary if he can no longer swallow. Teach the patient (if he’s still able to feed himself) or family members how to administer gastrostomy feedings.
• Provide emotional support. Prepare the patient and family for his eventual death, and encourage them to begin the grieving process. Patients with ALS may benefit from a hospice program.