698
Chapter 21: Neurocognitive Disorders
Table 21.2-3
Predisposing Factors for Delirium
Demographic characteristics
Age 65 years and older
Male sex
Cognitive status
Dementia
Cognitive impairment
History of delirium
Depression
Functional status
Functional dependence
Immobility
History of falls
Low level of activity
Sensory impairment
Hearing
Visual
Decreased oral intake
Dehydration
Malnutrition
Drugs
Treatment with psychoactive drugs
Treatment with drugs with anticholinergic properties
Alcohol abuse
Coexisting medical conditions
Severe medical diseases
Chronic renal or hepatic disease
Stroke
Neurological disease
Metabolic derangements
Infection with human immunodeficiency virus
Fractures or trauma
Terminal diseases
(Adapted from Inouye SK: Delirium in older persons.
N Engl J Med
.
2106;354(11):1157.)
Table 21.2-4
Precipitating Factors for Delirium
Drugs
Sedative–hypnotics
Narcotics
Anticholinergic drugs
Treatment with multiple drugs
Alcohol or drug withdrawal
Primary neurologic diseases
Stroke, nondominant hemispheric
Intracranial bleeding
Meningitis or encephalitis
Intercurrent illnesses
Infections
Iatrogenic complications
Severe acute illness
Hypoxia
Shock
Anemia
Fever or hypothermia
Dehydration
Poor nutritional status
Low serum albumin levels
Metabolic derangements
Surgery
Orthopedic surgery
Cardiac surgery
Prolonged cardiopulmonary bypass
Noncardiac surgery
Environmental
Admission to intensive care unit
Use of physical restraints
Use of bladder catheter
Use of multiple procedures
Pain
Emotional stress
Prolonged sleep depravation
(Adapted from Inouye SK: Delirium in older persons.
N Engl J Med
.
2106;354(11):1157.)
Table 21.2-2
Delirium Incidence and Prevalence in Multiple
Settings
Population
Prevalence
Range (%)
Incidence
Range (%)
General medical inpatients
10–30
3–16
Medical and surgical
inpatients
5–15
10–55
General surgical inpatients
N/A
9–15
postoperatively
Critical care unit patients
16
16–83
Cardiac surgery inpatients
16–34
7–34
Orthopedic surgery patients 33
18–50
Emergency department
7–10
N/A
Terminally ill cancer patients 23–28
83
Institutionalized elderly
44
33
N/A, not available.
Advanced age is a major risk factor for the development
of delirium. Approximately 30 to 40 percent of hospitalized
patients older than age 65 years have an episode of delir-
ium, and another 10 to 15 percent of elderly persons exhibit
delirium on admission to the hospital. Of nursing home
residents older than age 75 years, 60 percent have repeated
episodes of delirium. Male gender is also an independent risk
factor for delirium.
Delirium is a poor prognostic sign. Rates of institutional-
ization are increased threefold for patients 65 years and older
who exhibit delirium while in the hospital. The 3-month mor-
tality rate of patients who have an episode of delirium is esti-
mated to be 23 to 33 percent. The 1-year mortality rate for
patients who have an episode of delirium may be as high as
50 percent. Elderly patients who experience delirium while
hospitalized have a 21 to 75 percent mortality rate during that
hospitalization. After discharge, up to 15 percent of these per-
sons die within a 1-month period, and 25 percent die within
6 months.
Etiology
The major causes of delirium are CNS disease (e.g., epilepsy),
systemic disease (e.g., cardiac failure), and either intoxication or
