Morbidity and Mortality Rounds is adapted from WebM&M, an online journal and forum on patient safety and health care quality funded by the Agency for Healthcare Research and Quality. The site features monthly expert analyses of interesting cases of medical errors and patient safety problems submitted anonymously by readers.
Visit WebM&M at www.webmm.ahrq.gov.
Case Objectives
•State the key diagnostic differences between delirium and dementia.
•Describe the Confusion Assessment Method for workup of suspected delirium.
•Explain the risks associated with using physical restraints in geriatric inpatients.
•Describe the initial workup of delirium in a hospitalized patient.
Case & Commentary: Part 1
An 86-year-old woman, admitted with complaints of shortness of breath and cough, was found to have pneumonia. Her past medical history included cataract surgery, hypertension controlled with medications, and type 2 diabetes controlled by diet. She was ambulatory, lived alone, and at baseline completed all activities of daily living independently. According to her daughter, the patient was never disoriented. At admission, the patient appeared mildly dehydrated on physical examination. Her oxygen saturation was 94% on 2 liters oxygen by nasal cannula, and an arterial blood gas showed a normal pCO2 of 40 mmHg. Her daughter requested to spend the night at the bedside but was told she could not stay.
Overnight, the patient was noted to be disoriented by the nursing staff. She began pulling at her IV lines and attempting to get out of bed. The covering physician was called and ordered that the patient be placed in four-point restraints.
The following morning, the daughter returned to find her mother in restraints, speaking incoherently and severely short of breath. Upon finding her mother confused, the daughter asked the nurse what had happened and reiterated to the nurse that her mother had never been confused before.
Elderly hospitalized patients frequently develop altered mental status as a complication of their illness. Distinguishing delirium from dementia is a common problem for physicians, particularly those who work in hospitals or long-term care facilities. Up to 25% of geriatric general ward patients and as many as 80% of ICU patients experience delirium during hospitalization.1 Upon presentation to the emergency department, 26% of geriatric patients meet diagnostic criteria for delirium.2
Given the frequency of delirium, all patients should be screened for cognitive functioning at the time of hospital admission. Screening serves two important purposes: to assess for delirium upon admission and to provide a baseline if delirium subsequently develops during the hospitalization.
Delirium in the Hospital
In the inpatient setting, any change in mental status should be considered delirium until proven otherwise. In fact, published guidelines preclude making the diagnosis of dementia in the setting of delirium3; thus, diagnosis of dementia should be reserved for the outpatient setting. Although it is not mentioned whether formal cognitive screening was performed in this patient, the patient’s excellent functional status and the corroborating information obtained from her daughter make it unlikely that the patient suffered from dementia at baseline.
Prediction rules for delirium have been validated in medical4, and noncardiac5 and cardiac surgery6 patients. While each patient population has unique attributes, there are several common, important factors. First, preexisting cognitive deficits are the strongest risk factor for delirium.4-6 Patients with higher burden of illness, as measured by Acute Physiology, Age, and Chronic Health Evaluation (APACHE) scores7,8, or comorbidities5,6 are at higher risk of delirium. Those with laboratory abnormalities, such as a BUN/creatinine ratio ≥18 (a marker of dehydration), decreased albumin, or abnormal sodium, potassium, or glucose4-6, are also predisposed to develop delirium. Additionally, patients with preexisting sensory deficits (visual or hearing) are at risk for delirium due to decreased cognitive input. For medical patients, cognitive impairment, acuity of illness, visual changes, and dehydration were combined into a validated prediction rule.4 This patient’s pneumonia and dehydration placed her at moderate risk of delirium, even in the absence of preexisting cognitive or visual impairment.
Delirium poses several risks to the patient. First, a delay in diagnosis and assessment of underlying causative factors can cause the underlying condition to fester, resulting in worse physiologic function when delirium is discovered. Patients with the hyperactive and mixed variants of delirium are at risk for overmedication (particularly sedation). Delirium amplifies the risks of hospitalization and bed rest in older patients, including malnutrition, deconditioning, dehydration, iatrogenic infection (such as catheter-associated urinary tract infection or aspiration pneumonia), pressure ulcers, falls, and iatrogenic events.9-11 On a larger scale, delirious patients require more staff time12, resulting in less staff time for other patients.
As a result of all of these factors, delirium is associated with severe consequences for patients. In fact, the diagnosis of delirium carries a mortality risk equivalent to that of sepsis or an in-hospital acute myocardial infarction.11 Patients who develop delirium have longer length of stay, increased hospital costs, and increased posthospitalization costs.13,14 In a recent analysis, patients who developed delirium accrued $16,000 to $64,000 in additional medical costs over the year following hospitalization compared to age-, gender-, and comorbidity-matched controls.15