Alzheimer's disease: preventing and recognizing a misdiagnosis

The incidence of Alzheimer's disease (AD), representing about 50% of all dementias, is rising in the United States. By the year 2040 there will be an estimated 9 million persons with AD in the United States. The diagnosis of AD is sometimes made prematurely and incorrectly. A significant number of conditions, ranging from the irreversible to the fully reversible, can produce cognitive impairment, and thus may be mistaken for AD. These conditions include other forms of dementia, delirium, and pseudodementia and other psychiatric conditions. Knowledge of the most common of these conditions and their presenting symptoms and precipitating factors, combined with a thorough assessment, can prevent a misdiagnosis of AD. This article reviews several conditions that may be mistaken for AD. Actual case studies (with fictitious names) depict the typical presentation of some of them.