Elsevier

General Hospital Psychiatry

Volume 29, Issue 5, September–October 2007, Pages 442-445
General Hospital Psychiatry

Psychiatric–Medical Comorbidity
Delirium: patient characteristics that predict a missed diagnosis at psychiatric consultation

https://doi.org/10.1016/j.genhosppsych.2007.05.006Get rights and content

Abstract

Objective

This study evaluates patient characteristics that might predict a missed diagnosis of delirium prior to being seen by a psychiatric consultant.

Method

Study participants were assessed using quantitative standardized scales of cognitive function, delirium and physical impairment.

Results

Referring service personnel missed the diagnosis of delirium in 46% of psychiatric consultations. Two factors were associated with their failure to identify delirium accurately: use of a past psychiatric diagnosis to explain delirium symptoms and the presence of pain. Symptoms of delirium and quantitative scale scores did not distinguish between patients with whom diagnosis had been missed and those with accurate diagnoses.

Conclusion

The consulting physicians of patients with delirium often incorrectly turn to past psychiatric diagnoses and/or are distracted by the presence of pain and, thus, fail to accurately diagnose delirium.

Introduction

Delirium is a common mental disorder in medical and surgical inpatients. It is associated with higher mortality rates, longer lengths of hospital stay, poor functional recovery and increased likelihood of nursing home placement [1], [2], [3], [4], [5], [6]. Delirium is a psychiatric manifestation of an underlying medical illness. The importance of the rapid recognition and treatment of delirium cannot be overstated.

A prompt search for its underlying cause is one of the most important aspects in the management of delirium. Consulting psychiatrists, however, find that medical and surgical doctors often mistake delirium for other psychiatric illnesses such as depression or anxiety. This delays the diagnosis and treatment of delirium, and contributes to an exacerbation of the medical illness causing the symptoms. It also complicates the medical and nursing care provided by staff, who are typically untrained to deal with agitated and often combative behaviors in a medical or surgical ward setting.

The purpose of this study was to examine the factors, including patients' characteristics and symptoms of delirium, associated with a missed diagnosis of delirium by medical and surgical staff.

Section snippets

Method

This study investigated patients given a diagnosis of delirium by the psychiatric consultation team at Tokai University Hospital in Japan. Only patients who were diagnosed as having delirium, as assessed independently by two fully trained consultation psychiatrists (Y.K., M.K., or T.O.). were included. After providing informed consent, study participants were given the Mini-Mental State Examination (MMSE; a tool that had been validated with eight Japanese subjects) [7] to measure cognitive

Statistical analysis

For comparisons of parametric data in two groups, appropriate two-sample t tests were performed based on equal or unequal variances by Levene's test. Chi-square test was used to compare categorical data. When sample sizes were prohibitively small, we used Fisher's Exact Test.

Results

Of 48 patients who received a final psychiatric diagnosis of delirium, 26 (54%) were correctly diagnosed prior to referral. In 22 instances, the diagnosis had been missed. Among those with a diagnosis inconsistent with delirium, five were considered depressed, and five were anxious. Four were noted to have suicidal proclivities, and four others had unexplained somatic complaints. In six patients, the request was psychiatric evaluation or assessment of an unspecific mental condition. Other

Discussion

This study suggests that medical and surgical specialists fail to correctly diagnose delirium in almost half of all cases referred for psychiatric consultation. This rate is consistent with the study of Armstrong et al. [12], who reported a similar percentage (46%) in a Veterans Affairs setting. At a university teaching hospital setting in the United States, 63% of patients with delirium were incorrectly diagnosed by the referring service personnel [13].

It has long been suggested that a

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