Delirium Due to Medical Cause Often Misdiagnosed as Psychiatric Disorder



WASHINGTON – Delirium due to underlying medical conditions was misdiagnosed as a psychiatric disorder in a significant proportion of patients who were admitted to an inpatient geriatric psychiatric unit, a retrospective chart review found.

The analysis of charts from 112 consecutive patients admitted to Central Regional Hospital, Butler, N.C., with a diagnosis of a psychiatric disorder, showed that 27 (24%) were subsequently found to have delirium due to an underlying medical condition. All 27 also had prior psychiatric diagnoses. The results were reported at the annual meeting of the American Association for Geriatric Psychiatry.

"If a patient has a previous psychiatric history, physicians are not as scrupulous or as careful to screen them for underlying medical issues. They are more likely to send them to a psych unit, thinking all of their behavior manifestations are actually psychiatric. ... The message is be more careful and consider any behavioral manifestation as delirium until proven otherwise," Dr. Meera Balasubramaniam said in an interview.

Upon evaluation in the psychiatric unit, most of the patients were diagnosed with hyperactive delirium (23), with the other 4 having mixed delirium. Urinary tract infection was the most common medical etiology for the delirium (11), followed by medications (6), poor glycemic control (3), electrolyte disturbance (1), acute central nervous system events (1), and dehydration (1). The rest did not have a cause documented in the discharge summary, said Dr. Balasubramaniam, a psychiatry resident at Duke University, Durham, N.C.

Nearly half of the patients (12) had been referred from the emergency department, while another 11 had been sent from an inpatient medical unit. An additional 4 were referred from an inpatient psychiatry unit. Among the patients with delirium, the most common referral diagnosis was cognitive disorder (16), followed by psychotic disorder (7), and mood disorder (4).

The delirium group was significantly more likely than those without delirium to be transferred to medical units (41% vs. 4%), and was also more likely to be subsequently discharged to a higher level of care, such as assisted living or skilled nursing, although this was not statistically significant (33% vs. 28%). "The overall outcome was poorer than if the delirium had been recognized in the first place ... There’s a lot of expense involved," she commented.

Visual and hearing impairment were significantly more likely to be present in the patients with delirium, compared to those without, but no differences were found with regard to age, past psychiatric history, number or type of psychotropic medications, or Charlson comorbidity index, she and her associates reported in a poster.

The bottom line, she said: "Even if it’s a patient who has a previous psych history, be careful about making sure they don’t have any underlying medical causes. Rule that out before sending them to a psych unit."

Dr. Balasubramaniam stated that she has no disclosures.

Next Article: