Cognitive disorders and delirium are neuropsychiatric syndromes that occur frequently in patients with cancer, particularly in those with advanced disease. Occurrence rates range from 28% to 48% in patients with advanced cancer on admission to hospital or hospice,[1-3] and approximately 90% of these patients will experience delirium in the hours to days before death.[3-5] The term acute confusional state has also been used to describe this syndrome; in the last days of life, the condition sometimes referred to as terminal restlessness probably represents a terminal delirium.[6] Although delirium clearly has a recognized association with the dying phase, many episodes of delirium are reversible; therapeutic intervention can result in delirium reversal, or at least improvement, in 30% to 75% of episodes.[3,5,7-10] Variability in reported occurrence rates and clinical outcomes most likely reflects sampling from different clinical settings or different stages in the clinical trajectory of cancer, in addition to inconsistency in diagnostic terminology.[11] The prevention of delirium in the patient with cancer has not been systematically examined, but studies in elderly medical patients suggest that early identification of risk factors reduces the occurrence rate of delirium and the duration of episodes.[12]

Delirium has been defined as a disorder of global cerebral dysfunction characterized by disordered awareness, attention, and cognition.[13] In addition, delirium is associated with behavioral manifestations. The fourth edition of the Diagnostic and Statistical Manual for Mental Disorders (DSM-IV) cites the core clinical criteria for diagnosis as follows:[14]

• A disturbance of consciousness with reduced clarity of awareness and attention deficit.
• Other cognitive or perceptual disturbances.
• Acuity of onset (hours to days) and fluctuation over the course of the day.
• The presence of an underlying cause such as a general medical condition (e.g., hypoxia or electrolyte disturbance), medication, a combination of etiologies, or indeterminate etiology.

Other associated noncore clinical criteria features include sleep-wake cycle disturbance, delusions, emotional lability, and disturbance of psychomotor activity. The latter forms the basis of classifying delirium into three different subtypes:[15,16]

1. Hypoactive.
2. Hyperactive.
3. Mixed, with both hypoactive and hyperactive features.

References

1. Minagawa H, Uchitomi Y, Yamawaki S, et al.: Psychiatric morbidity in terminally ill cancer patients. A prospective study. Cancer 78 (5): 1131-7, 1996.  [PUBMED Abstract]
   
   
2. Pereira J, Hanson J, Bruera E: The frequency and clinical course of cognitive impairment in patients with terminal cancer. Cancer 79 (4): 835-42, 1997.  [PUBMED Abstract]
   
   
3. Lawlor PG, Gagnon B, Mancini IL, et al.: Occurrence, causes, and outcome of delirium in patients with advanced cancer: a prospective study. Arch Intern Med 160 (6): 786-94, 2000.  [PUBMED Abstract]
   
   
4. Massie MJ, Holland J, Glass E: Delirium in terminally ill cancer patients. Am J Psychiatry 140 (8): 1048-50, 1983.  [PUBMED Abstract]
   
   
5. Bruera E, Miller L, McCallion J, et al.: Cognitive failure in patients with terminal cancer: a prospective study. J Pain Symptom Manage 7 (4): 192-5, 1992.  [PUBMED Abstract]
   
   
6. Travis SS, Conway J, Daly M, et al.: Terminal restlessness in the nursing facility: assessment, palliation, and symptom management. Geriatr Nurs 22 (6): 308-12, 2001 Nov-Dec.  [PUBMED Abstract]
   
   
7. Gagnon P, Allard P, Mâsse B, et al.: Delirium in terminal cancer: a prospective study using daily screening, early diagnosis, and continuous monitoring. J Pain Symptom Manage 19 (6): 412-26, 2000.  [PUBMED Abstract]
   
   
8. Maddocks I, Somogyi A, Abbott F, et al.: Attenuation of morphine-induced delirium in palliative care by substitution with infusion of oxycodone. J Pain Symptom Manage 12 (3): 182-9, 1996.  [PUBMED Abstract]
   
   
9. Tuma R, DeAngelis LM: Altered mental status in patients with cancer. Arch Neurol 57 (12): 1727-31, 2000.  [PUBMED Abstract]
   
   
10. Breitbart W, Gibson C, Tremblay A: The delirium experience: delirium recall and delirium-related distress in hospitalized patients with cancer, their spouses/caregivers, and their nurses. Psychosomatics 43 (3): 183-94, 2002 May-Jun.  [PUBMED Abstract]
    
    
11. Lawlor PG: The panorama of opioid-related cognitive dysfunction in patients with cancer: a critical literature appraisal. Cancer 94 (6): 1836-53, 2002.  [PUBMED Abstract]
    
    
12. Inouye SK, Bogardus ST Jr, Charpentier PA, et al.: A multicomponent intervention to prevent delirium in hospitalized older patients. N Engl J Med 340 (9): 669-76, 1999.  [PUBMED Abstract]
    
    
13. Lipowski ZJ: Delirium in the elderly patient. N Engl J Med 320 (9): 578-82, 1989.  [PUBMED Abstract]
    
    
14. Delirium, dementia, and amnestic and other cognitive disorders. In: American Psychiatric Association.: Diagnostic and Statistical Manual of Mental Disorders: DSM-IV. 4th ed. Washington, DC: American Psychiatric Association, 1994, pp 123-33. 
    
    
15. Clinical features, course, and outcome. In: Lipowski ZJ: Delirium: Acute Confusional States. New York, NY: Oxford University Press, 1990, pp 54-70. 
    
    
16. Camus V, Burtin B, Simeone I, et al.: Factor analysis supports the evidence of existing hyperactive and hypoactive subtypes of delirium. Int J Geriatr Psychiatry 15 (4): 313-6, 2000.  [PUBMED Abstract]
    
    

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