Delirium, a clinical syndrome characterized as an acute disorder of attention and cognitive function, is the most frequent complication of hospitalization for elders and a potentially devastating problem. Delirium often is unrecognized despite sensitive methods for its detection, and its complications may be preventable.
[...] Drug and alcohol withdrawal are important and often unsuspected causes of delirium in the elderly. Environmental factors, such as unfamiliar surroundings, sleep deprivation, deranged schedule, frequent room changes, sensory overload, or sensory deprivation, may aggravate delirium in the hospital. Psychosocial factors, such as depression, psychological stress, pain, or lack of social supports, also may precipitate delirium. Incidence and Prevalence In the elderly, the prevalence of delirium at hospital admission is 10 to 40%. Delirium develops anew in 25 to 56% of patients during hospitalization. [...]
[...] These two conditions are differentiated by the acute onset of symptoms in delirium (dementia is much more insidious) and the impaired attention and altered level of consciousness associated with delirium. The differential diagnosis also includes depression and nonorganic psychotic disorders. Although paranoia, hallucinations, and affective changes can occur with delirium, the key features of acute onset, inattention, altered level of consciousness, and global cognitive impairment assist in the recognition of delirium. At times, the differential diagnosis can be difficult, particularly with an uncooperative patient or when an accurate history is unavailable. [...]
[...] Although not cardinal elements, other features frequently occurring during delirium include disorientation, cognitive deficits, psychomotor agitation or retardation, perceptual disturbances such as hallucinations and illusions, paranoid delusions, and sleep-wake cycle reversal. Diagnosis and Evaluation The cornerstone of evaluation of delirium is a comprehensive history and physical examination. The first step in evaluation should be to establish the diagnosis of delirium through cognitive assessment and determine whether the present condition represents an acute change from the patient's baseline cognitive function. Because cognitive impairment may not be apparent during conversation, brief cognitive screening tests, such as the Mini-Mental Status Examination and the Confusion Assessment Method, should be used. [...]
[...] Medications, the most common remediable cause of delirium, contribute to delirium in 40% of cases. Insufficiency or failure of any major organ system, particularly renal or hepatic failure, can precipitate delirium. Hypoxemia and hypercarbia have been associated with delirium. Clinicians must be attuned to occult respiratory failure, which in the elderly often lacks the usual signs and symptoms of dyspnea and tachypnea and can be missed by measuring oxygen saturation alone. Acute myocardial infarction or heart failure can be manifested as delirium in an elderly patient without the usual symptoms of chest pain or dyspnea. [...]
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