Every clinician should be able to recognize delirium. As the most common behavioral complication of cancer treatment, delirium is often a harbinger of a serious medical disorder and is associated with increased morbidity and mortality, and increased length and cost of hospital stay.1,2,3,4,5 In addition to its physical implications, delirium typically is a terrifying experience that has a lasting psychological impact on patients and their families. The experience of delirium is remembered by the majority of patients and may result in long-term psychological morbidity for patients and their families.6 Delirium interferes with the patient's ability to communicate and hinders the clinician's attempts to evaluate physical symptoms and to perform a detailed physical examination. Delirious patients are more likely to have an accidental fall or other injury during their hospital stay.7 A diagnosis of delirium is a predictor of longer hospital stay and is also associated with more difficulty in identifying posthospital placement options for the patient.
Many terms have been used to describe the syndrome subsumed under the DSM-IV-TR syndrome of delirium (Table 7-1). Terms such as acute confusional state, acute brain failure, organic brain syndrome, and encephalopathy are still used by different clinicians to describe patients who meet criteria for delirium. This nosologic imprecision inevitably results in confusion among clinicians and families, and hampers the development of standardized approaches to assessment and management.8 Because delirium occurs so frequently in intensive care settings, it is still sometimes referred to as "ICU psychosis" and, unfortunately, may be regarded almost as a natural consequence of intensive care (the so-called "ICU psychosis").9,10,11
TABLE 7-1.Evaluation of the Delirious Patient ||Download (.pdf) TABLE 7-1. Evaluation of the Delirious Patient
History and chart review; attention to medications
Clinical interview and mental status examination
Physical examination; attention to neurological status
Laboratory assessment: complete blood count with differential and platelets, electrolytes, creatinine, BUN, calcium, magnesium, albumin, liver function tests, thyroid, glucose, RPR function tests, O2 saturation/arterial blood gases
Chest x-ray, EKG
Urine, blood cultures, cerebral spinal fluid studies, if indicated
Serum/urine drug and alcohol screens, serum drug levels
As indicated: B12 and folate levels, serum drug levels, EEF brain CT/MRI
Lipowski12 defined delirium as "a transient organic syndrome characterized by acute onset, global impairment of cognitive function, altered level of consciousness, inability to attend, psychomotor agitation or retardation, and disruption of sleep–wake cycle." This definition takes into account criteria not required by the Diagnostic and Statistical Manual of the American Psychiatric Association (Table 7-1).13 Several important points are relevant to both definitions of delirium:
Delirium is essentially a disorder of attention. This is because the ability to focus, sustain, and redirect attention is the bedrock of all cognition and behavior. As a disorder of attention, delirium will produce ...