Assessment, Diagnosis, and Monitoring
The diagnosis of delirium should be considered for any patient with cancer demonstrating an acute onset of agitation or uncooperative behavior, personality change, impaired cognitive functioning, altered attention span, fluctuating level of consciousness, or uncharacteristic anxiety or depression. However, the diagnoses of delirium and cognitive impairment are frequently missed and poorly documented.[1-5]
Medical and nursing staff, as well as family members, may attribute a functional cause to some of the early, prodromal, and more subtle signs of delirium such as increased anxiety, restlessness, and emotional lability. Failure to recognize delirium is particularly likely if the patient is encountered in a transient lucid phase, which can commonly occur as part of the fluctuating nature of delirium. Delirium is most frequently misdiagnosed as depression or dementia.[7-10] The hypoactive subtype is considered especially likely to be misdiagnosed as depression.
Differentiating delirium from dementia or recognizing delirium superimposed on dementia can be difficult because of some shared clinical features such as disorientation and impairment of memory, thinking, and judgment.[11-13] However, dementia typically appears in relatively alert individuals; disturbance of consciousness is not a common feature. The temporal onset of symptoms of delirium is acute (hours to days), not insidious (months to years) as in dementia. In elderly patients with cancer, delirium is often superimposed on dementia, giving rise to a particularly difficult diagnostic challenge. In this situation, the diagnosis may become more apparent when delirium fails to reverse or when some features of delirium, especially cognitive impairment, persist. Dementia is often then the most likely explanation for a persistent or residual cognitive deficit.
Vigilance on the part of nursing staff and a systematic approach to recording serial observations assist in the detection of delirium. Regular cognitive screening facilitates the diagnosis of delirium in cancer patients. Instruments such as the Mini-Mental State Examination (MMSE), Blessed Orientation Memory and Concentration Test (BOMC), and Confusion Assessment Method (CAM) have favorable psychometric properties and are brief enough to allow repeated administration in cancer patients.[16-18] The BOMC and MMSE screen for cognitive impairment and require active patient participation in assessment. The Bedside Confusion Scale also requires active patient participation; however, it is remarkably brief, and its psychometric potential as a screening instrument compares favorably with the CAM. The CAM does not require formal patient participation. The Memorial Delirium Assessment Scale (MDAS) and Delirium Rating Scale-Revised-98 have been validated as having diagnostic and severity rating potential.[20,21] The MDAS allows prorating of scores when a patient cannot actively participate in testing for reasons such as dyspnea or fatigue.References
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