International psychogeriatrics
-
This prospective study determined the incidence and prevalence of delirium in 235 consecutive subjects over age 70 admitted to a general medicine hospital service. The DSM-III criteria for delirium were operationalized. ⋯ Analysis of these data indicates that the DSM-III criteria describe a discrete, recognizable syndrome. However, some of the symptoms are more specific than others in identifying the syndrome in this population.
-
It has long been known that the conventional electroencephalogram (EEG) is a useful tool in the evaluation of delirium. There are moderate correlations between the amount of slowing seen on EEG and the degree of confusion or level of arousal observed among delirious patients. The usefulness of the EEG for assessment and diagnosis in this area has been limited, however, by: (a) difficulties in assessing the significance of slow-wave activity, (b) problems in detecting changes in relative EEG power, and (c) the logistical problem of lengthy recording sessions with agitated patients. ⋯ Delirium shares electrophysiological characteristics with other organic mental syndromes, however, where quantitative EEG has been shown to be useful. Furthermore, analysis of digital EEG data is inherently superior to visual inspection in assessing the distribution of EEG power among different frequency bands. Previous studies, as well as data presented here, suggest that quantitative EEG is a clinically useful supplement to the conventional EEG for the assessment of elderly patients with delirium.
-
Delirium is often considered a global and nonspecific alteration in cerebral function. However, the recent clinical evidence for heterogeneity within the syndrome of delirium suggests that different systems of the brain may be important in different kinds of delirium. Some forms of delirium, such as anticholinergic toxicity and hepatic encephalopathy, may be caused by drugs or toxins acting on specific brain neurochemical systems. ⋯ Little is known about changes in these systems with aging. The well-known degeneration in cholinergic systems in Alzheimer's disease, and the sensitivity of individuals with Alzheimer's disease to anticholinergic toxicity, suggest a role of central cholinergic systems in anticholinergic delirium in demented patients. Further research into the involvement of the other systems in aging and delirium apparently would be fruitful.
-
"Delirium" is a reversible confusional state. It results from widespread but reversible interference with the function of cortical neurons, as documented by diffuse slowing on EEG and decreases in cerebral metabolic rate. Delirium can be due to impairments in neuronal metabolism, in neurotransmission (notably cholinergic), or in input from subcortical structures. ⋯ So many disorders can precipitate delirium that the differential diagnosis tests every facet of one's knowledge of medicine. With aging, both normative changes in the brain and the increasing incidence of brain diseases predispose to the development of delirium. The brain damage responsible for a dementia can sensitize to the development of a superimposed delirium.
-
Review Case Reports
Benzodiazepine-induced and anticholinergic-induced delirium in the elderly.
Encompassing the range from subtle cognitive impairments to frank delirium, toxicity due to benzodiazepines and to anticholinergic-containing compounds is reviewed. For benzodiazepines, an extensive literature suggests that they impair immediate and delayed memory, psychomotor performance, and subjective complaints of station. ⋯ Toxicity from anticholinergic compounds, detected by anticholinergic drug levels, is significantly correlated with the presence and severity of delirium in a number of settings including postoperative patients and elderly nursing home residents. Possible means of identifying the syndrome by prediction of dose and type of medication, as well as by quantitative EEG, are reviewed.