Medicina

Amyotrophic Lateral Sclerosis: Lou Gehrig's Disease
ANNE D. WALLING, M.D.
University of Kansas School of Medicine
Wichita, Kansas

Amyotrophic lateral sclerosis (ALS), commonly called Lou Gehrig's disease, is a progressive neuromuscular condition characterized by weakness, muscle wasting, fasciculations and increased reflexes. Approximately 30,000 Americans currently have the disease.The annual incidence rate is one to two cases per 100,000. The disease is most commonly diagnosed in middle age and affects more men than women. It usually presents with problems in dexterity or gait resulting from muscle weakness. Difficulty in speaking or swallowing is the initial symptom in the bulbar form of the disease. Over a period of months or years, patients with ALS develop severe,progressive muscular weakness and other symptoms caused by loss of function in both upper and lower motor neurons. Sphincter control, sensory function, intellectual abilities and skin integrity are preserved. Patients become completely disabled, often requiring ventilatory support and gastrostomy. Death usually occurs within five years of diagnosis and is attributed to respiratory failure or cachexia.The etiology of the disease is unknown. Current research is focused on abnormalities of neuronal cell metabolism involving glutamate and the role of potential neurotoxins and neurotrophic factors. New drugs are being developed based on these theories. Current management involves aggressive, individualized alleviation of symptoms and complications.


Amyotrophic lateral sclerosis (ALS) was firstdescribed in 1869.1 It is frequently referred to as "Lou Gehrig's disease" in memory of the famous baseball player who died of ALS in 1941.2 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.3-5(pp9-15) The clinical picture varies, depending on thelocation and progression of the pathologic changes. Diagnostic criteria of the World Federation of Neurology (the "El Escorial criteria")6 can help define and classify ALS (Table 1).


Illustrative Case 1


Bulbar Form
Relatives of a 61-year-old woman reported that she appeared to have difficulty concentrating during long discussions. Apart from longstanding thyroid and estrogen supplementation,her medical history was unremarkable. Review of systems, a mental status examination and a physical assessment were normal. The patient was a psychologist who usually read several books a week and had an active social life, including competitive bridge and vigorous daily exercise. She had no symptoms of depression, or mental or intellectual difficulties, and denied alcohol or substance abuse. Shebelieved her family's concerns were unwarranted but eventually conceded that her voice "just wore out" during prolonged conversations.

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|TABLE 1 |
|Diagnostic Criteria for ALS |
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|Positive features |
|• Definite ALS |
|--LMN and UMN signs in three to four regions |
|-- Evidence of progression |
|• Probable ALS|
|LMN and UMN signs in at least two regions with UMN above |
|LMN signs and evidence of progression |
|• Possible ALS |
|--LMN and UMN in one region |
|--UMN in two regions |
|--LMN above UMN signs |
|--LMN and UMN signs...