Diagnosis and management of geriatric patients exhibiting symptoms and signs of impaired cognitive functioning can make a critical difference to their overall health and their ability to function independently. Impaired cognitive function can be acute in onset, or it can be slowly progressive. The major causes of impaired cognition in the geriatric population are delirium and dementia. As more people live into the tenth decade of life, the chance that they will develop some form of dementia increases substantially. Community-based studies report a prevalence of dementia as high as 47% among those 85 years of age and older. Recent evidence suggests that the incidence of dementia is decreasing in more recent cohorts of people studied (Larson et al, 2013; Satizabal et al, 2016). Between 25% and 40% of older patients admitted to acute care medical and surgical services are delirious on admission or develop delirium during their hospital stay. In nursing homes, 50% to 80% of those older than 65 years of age have some degree of cognitive impairment which can range from mild cognitive deficits to end-stage dementia. Dementia is a major risk factor for delirium, and delirium is often superimposed on dementia in both hospital and community settings, can persist for days to weeks after discharge from an acute hospital, and is a risk factor for functional decline and mortality. Both dementia and delirium are associated with high health-care costs (Amjad et al, 2016; Okie, 2011).
Misdiagnosis, overdiagnosis, or underdiagnosis and resulting inappropriate management of conditions associated with cognitive impairment in geriatric patients can cause substantial morbidity among the patients, hardship for their families and caregivers, and excessive health-care expenditures. This chapter provides a practical framework for diagnosing and managing geriatric patients who demonstrate “confusion” or signs of cognitive impairment. We focus on the most common causes of confusion in the geriatric population—delirium and dementia—although a variety of other disorders can cause the same or similar signs.
Imprecise definition of the abnormalities of cognitive function in older patients labeled as “confused” has led to problems in diagnosis and management. Descriptions such as impairment of cognitive function or cognitive impairment coupled with careful documentation of the timing and nature of specific abnormalities provide more precise and clinically useful information. Screening for dementia is controversial and is not recommended by the U.S. Preventive Services Task Force (Moyer, 2014). The best method of evaluating a patient suspected of cognitive impairment or dementia is a thorough mental status examination.
MENTAL STATUS EXAMINATION
In acutely ill older patients, identification of delirium can be accomplished with the confusion assessment method (CAM). There are many cognitive tests that can be used to identify patients with dementia (Tsoi et al, 2015). The Mini-Cog is useful in screening for cognitive impairment and dementia. These tests are discussed later in the chapter.