Alzheimer's disease: clinical features, pathogenesis, and treatment.

Alzheimer's disease is an insidious degenerative disease of the brain and is the leading cause of dementia in the U.S. Numerous etiologies have been postulated, including a large body of evidence suggesting a slow viral infection, possibly in genetically predisposed individuals, but this remains to be proven. Differential diagnosis is based primarily on exclusion of other treatable forms of dementia. Neurochemical studies suggest a cholinergic deficit; thus primary emphasis in treatment has been directed at enhancing cholinergic activity. Choline and lecithin supplementation generally has been ineffective. Results with physostigmine are encouraging and further studies with this drug prototype are needed. Physostigmine's clinical usefulness is limited, however, due to peripheral side effects and its short duration of action. Other pharmacological approaches, such as naloxone, neural metabolic enhancers, stimulants, and vasopressin analogs, have been investigated. The clinical features and pathology of the disease are reviewed.