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DELIRIUM: EPIDEMIOLOGY
The incidence and prevalence of delirium have been difficult to ascertain, in part, because the syndrome has gone by various names in various settings and because there have been no generally accepted criteria for diagnosis. A more important issue may be that delirium is often unrecognized or undocumented by family physicians, internists, and surgeons?the doctors who see it most. The following case illustrates this problem.
The Case of Mr. G.-Mr. G., a 76-year-old man with hypertension, atrial fibrillation, dilated cardiomyopathy, and diabetes mellitus, was referred to the psychiatric consultation service thirteen days after palliative surgery for cancer. The evaluation was requested because the patient had “blunted affect” and failure to adjust.”
On each of the six days before consultation, the patient’s physical therapist had described him as poorly motivated or refusing to participate in treatment. On three of the four nights before consultation, the nursing staff had documented insomnia, agitation, or incontinence.
Two days before consultation, at 4:00 a.m., the surgical resident was asked to see Mr. G. for possible weakness of the left arm. Neurological examination was normal, and the patient was observed to be alert and “oriented X 3,” though he also had “flat affect” and needed “repeated coaxing” to answer questions.
One day before consultation, at 6:45 a.m., the attending surgeon described Mr. G. as “depressed” but continued to plan for discharge that afternoon. At 11:00 a.m., the social worker noted that the patient had “waxing/waning alertness” and “seemed unable to understand conversation.” At 11:15, the surgical resident was asked to see Mr. G. because the social worker feared he was unfit to travel. The resident found Mr. G. “distracted, and not appropriately responsive to commands and questioning.” The patient’s affect was judged to be “noticeably blunted and has been worsening given prognosis.” The resident decided to request psychiatric consultation for “altered mental status with blunted affect. . . r/o major depressive disorder.” Discharge was canceled. That afternoon, the patient did not recognize his daughter, but sometime later the social worker reported that Mr. G. was “oriented and more appropriate in
responses.”
At 9:40 that night, the psychiatric consultation resident found Mr. G. alert, dressed in a hospital gown, and lying in bed. The patient had marked psychomotor retardation and a short attention span. His behavior was generally appropriate to the situation, though when the resident left the room for several minutes she returned to find him sitting nude on the side of his bed in front of an open door.
Mr. G. denied family or personal history of psychiatric disorder. He was a college graduate, had worked as an accountant, and had been happily married for forty-nine years. He did not drink alcohol or use illicit drugs. The patient described his premorbid personality as “not much of a fighter” and said that his usual mood was “as middle as you can be.”
Mr. G.’s speech was brief, with occasional perseveration and one para-phasic error. (When asked to copy the interlocking pentagons on the Mini-Mental State Examination [MMSE], he refused, saying: “Not under these circumcisions.”) The patient initially described his mood as
“punk” and said that he was disappointed by the prognosis for his tumor. Later, he reported that he was “happy as usual,” and when asked to recall three words to test his memory, he said: “You must be kidding.” He denied suicidal thoughts, hallucinations, and delusions.
Mr. G.’s score on the MMSE was 15/30, with poor performance on all sections of the test. Although he was oriented to place, he gave the date (1994) as “1960 or 1970.”
The next day I found the patient alert, with mild psychomotor retardation. He refused to be examined, saying that he was sick of answering questions and wanted to rest. His mood appeared to be sad and irritable. The patient’s daughter reported that Mr. G. had been well oriented that morning but had had visual hallucinations the night before. She believed that her father was understandably disappointed and that he was impatient to be discharged. The daughter immediately agreed when I told her that Mr. G. was delirious?she had seen her father in a similar state during an illness the year before and recognized its signs.
Review of the chart revealed that four days before consultation, Mr. G.’s hematocrit was 30.9, his white blood cell count 10,400, his serum urea nitrogen 22, and his creatinine 1.5. On the day of consultation, hematocrit was 29.2, white blood cell count 16,100, serum urea nitrogen 37, and creatinine 1.8. Several other metabolic tests (e.g., bilirubin) were also abnormal, but stable, and the patient had been afebrile. Mr. G.’s medications included oxycodone and temazepam, both of which he had been given in recent days.
I told the attending surgeon that Mr. G. was saddened by his situation but did not seem to have an affective disorder. The surgeon was relieved by my report and said that he would proceed with discharge the next day. When I added that the patient was delirious?probably from the combined effects of medications, anemia, decreased renal function, and possible infection?and that he might get worse as he traveled to his home in another state, the surgeon (a very experienced one) tried to reassure me. “Delirium?” he said, “We see that all the time.”
The case of Mr. G. is typical in that delirium usually occurs in non-psychiatric settings, where it may not be recognized or documented. In recent years, however, with increasing agreement on nomenclature and diagnostic criteria, with the development of bedside methods for the detection of delirium, and with growing interest in the care of elderly persons, much has been done to establish the syndrome’s prevalence and incidence among those who are most vulnerable.
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