Cases & Commentaries

Delirium or Dementia?

Spotlight Case
Commentary By James L. Rudolph, MD, SM

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
intravenous 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 intensive care unit 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 delirium (3); 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 medical (4),
and non-cardiac (5) and
cardiac surgery (6)
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) scores
(7,8),
or comorbidities (5,6)
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
glucose (4-6),
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
(Table).(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 physiological function when delirium is
discovered. Patients with the hyperactive and mixed variants of
delirium (see below for explanation) are at risk for overmedication
(particularly sedation). Delirium amplifies the risks of
hospitalization and bedrest 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 time
(12),
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 post-hospitalization 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)

There are three psychomotor
variants of delirium: hyperactive (prevalence, 25%), hypoactive
(prevalence, 50%), and mixed disorder, with features of both
(prevalence, 25%).(16)
This patient appeared to have the hyperactive form of delirium. As
mentioned above, patients with the hyperactive and mixed disorders
are more likely to be physically and chemically restrained. Indeed,
this patient was placed in physical restraints when she became
confused and hyperactive. The Joint Commission has published
standards for restraint use. The key elements of the standards'
implementation are "the device's intended use (such as physical
restriction), its involuntary application, and/or the identified
patient need that determines whether use of the device triggers the
application of these standards."(17) As
such, consideration should be given to the following questions
prior to restraining a patient:

  • What is the intended effect of the
    restraint?
  • Is there another means by which the
    intended effect can be achieved?
  • Is this the least invasive
    restraint?
  • Is the use of restraints in the
    patient's best interest?
  • Am I restraining the patient for
    secondary benefits (to limit phone calls/pages, to assuage nursing
    requests, too busy to see patient, etc.)?
  • When is the restraint going to be
    removed?

Although necessary at times, the
use of restraints must be considered carefully prior to application
for three key reasons. First, restraints have been found to be
independently associated with the development of
delirium.(18,19)
Second, restraints may exacerbate underlying hyperactive behavior.
Finally, by restricting patients to bedrest, restraints further
limit external stimuli, which in itself may increase the risk for
delirium.(20)

Case & Commentary: Part 2

The doctor was called, and
an arterial blood gas was performed. The patient's PaO2 was 91
mmHg, but the PaCo2 was 58 mmHg, a marked increase since admission.
Despite the patient's deteriorating clinical condition, the
patient's worsening level of consciousness was attributed to
"senile dementia" and not impending respiratory failure (as
evidenced by the significant carbon dioxide retention). No further
action was taken. Over the course of the day, the patient developed
worsening respiratory distress and became comatose, and eventually
was transferred to the intensive care unit. She subsequently
developed respiratory failure requiring intubation and renal
failure requiring dialysis. Her condition did not significantly
improve, and she eventually died 2 weeks later.

This patient was incorrectly diagnosed with
dementia, despite a presentation most consistent with delirium. The
diagnosis of delirium follows the diagnostic algorithm of the
Confusion Assessment Method (CAM) and involves elements of history
and physical examination.(21)
The CAM algorithm has four features (Figure):

  • Feature 1 is acute onset and
    fluctuating course
    . Presence of this feature can generally be
    obtained from family and nursing history.
  • Feature 2, inattention, is
    assessed through brief cognitive assessment such as serial 7s (take
    the number 100 and subtract 7, keep going until I tell you to
    stop); digit span (I am going to read you some numbers and I want
    you to repeat them to me backwards); or asking the patient to
    recite months of the year or days of the week backwards.
  • Feature 3, disorganized
    thinking
    , can be assessed via response to interview questions.
    For example, does the patient respond inappropriately or
    tangentially?
  • Feature 4, disturbance of
    consciousness
    , helps identify the three psychomotor variants
    (hyperactive, hypoactive, mixed disorder).

Patients demonstrating features
1 and 2 along with either feature 3 or 4 should be considered to
have delirium until proven otherwise.(11) The diagnosis of "senile dementia" is not appropriate
in the setting of acute illness. The acute onset of confusion and
hyperactivity in this case should have prompted cognitive
assessment for inattention and disorganized thinking; such an
assessment would likely have led to the correct diagnosis of
delirium.

A thorough history and physical
examination are required for patients suspected of having delirium.
The neurological examination is especially important because while
acute, focal neurological changes require neuroimaging, patients
without such changes can usually have neuroimaging deferred,
reserved for situations in which the cause cannot be determined
from a medical/metabolic workup.(22)
Core laboratory tests to identify electrolyte abnormalities, renal
function, and infection (complete blood count and urinalysis) are
warranted in all patients. The history and physical examination
should guide further laboratory testing. An arterial blood gas was
appropriately performed in this case, but it appears that the
physician failed to tie the results (marked carbon dioxide
retention) together with the patient's delirium.

All patients should have a thorough review of
medications that may contribute to delirium, particularly
benzodiazepines, anticholinergic medications, and psychoactive
medications.(23)
All medications that can precipitate delirium should be
discontinued or have dosages lowered. Further consideration should
be given to drugs that have recently been stopped and may cause a
withdrawal syndrome (alcohol, chronic opioids, antidepressants,
etc.).

Delirium is treated by
identifying and remedying the underlying causes. Because of the
associated morbidity and mortality, multiple causative pathways and
treatments may need to be pursued and/or instituted simultaneously.
Such causes might include electrolyte abnormalities, assessment of
renal function, additional workup for other sources of infection
(urinalysis or lumbar puncture if indicated), fecal impaction, and
other myocardial/pulmonary causes of hypoxemia.

In this case, the best single
explanation for the patient's deterioration is progressive
pneumonia resulting in worsened gas exchange and carbon dioxide
retention. Thus, delirium was likely the presenting symptom of
impending hypercarbic respiratory failure. More aggressive
treatment of the pneumonia and associated CO2 retention was
warranted. Additionally, medication review should have been
conducted, resulting in the removal of sedative or anticholinergic
medications. It is unclear why further workup or treatment was not
pursued in this case.

In this case, the patient's
daughter was able to inform clinicians that her mother had never
been confused or disoriented prior to hospitalization. In addition
to their role in establishing the historical, behavioral, and
cognitive baseline, family members and caregivers are an
underutilized resource in the treatment of patients with delirium.
For example, family members serve as a re-orienting stimulus for
patients. In an average day on a hospital medical ward, 20-30
different staff members will enter a patient's room (nursing,
nutrition, housekeeping, housestaff, consultants, attending
physicians, etc.). As a result, patients with impaired cognition
may misinterpret the in-room presence of these staff members,
leading to paranoid thoughts and delusions. Family members or
caregivers may be the only people whom the patient recognizes and,
thus, can serve to reassure the patient about his or her current
location and medical situation. Family or caregivers can also
provide cognitive stimulation for the patient, such as by playing
cards, doing crossword puzzles together, or viewing family photos.
Additionally, family may be willing to participate in the care of
the patient, which may reduce patient agitation, provide a
constructive outlet for family concern, and decrease staff
requirements.(24) As
a result, family should be involved in the care of the delirious
patient to the extent possible. Formal "visiting hours" may need to
be relaxed or eliminated to ensure that the family is able to be
present to calm the patient during periods of
confusion.

The failure to recognize
delirium in this patient may have delayed recognition of her
worsening pneumonia, which in turn led to a failure to escalate the
level of care. Cognitive assessment at admission and appropriate
use of collateral information from the patient's daughter might
have helped the physician realize that the patient's altered mental
status represented delirium and not dementia. Delirium is
associated with severe clinical consequences, so earlier
recognition of delirium should have prompted a thorough search for
precipitants and aggressive treatment of the underlying illness.
Actively encouraging the family's participation in care may have
helped identify delirium earlier and may have obviated the need for
physical restraints in this case. In short, this patient's death
may have been preventable with optimal care; as such, this case
represents an instructive cautionary note.

Take-Home Points

  • Delirium, an acute change in cognition
    and attention, is common, morbid, and costly.
  • All change in mental status should be
    assumed to be delirium until proven otherwise.
  • The treatment of delirium is to identify
    and remedy the underlying causes.
  • Elements of the hospital environment can
    contribute to delirium and expose patients to safety risk.
  • Family members and caregivers are
    crucial to the diagnosis and management of delirium. Incorporating
    their contribution into the plan of care is strongly
    recommended.

James L.
Rudolph, MD, SM

Assistant Professor of Medicine

Harvard
Medical School

Associate Physician

Brigham
and Women's Hospital

Staff
Physician

VA Boston Healthcare
System

Faculty Disclosure: Dr. Rudolph has
declared that neither he, nor any immediate member of his family,
has a financial arrangement or other relationship with the
manufacturers of any commercial products discussed in this
continuing medical education activity. In addition, the commentary
does not include information regarding investigational or off-label
use of pharmaceutical products or medical devices.

References

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Table

Table. Delirium Prediction Rule for Patients
Based on Admission Characteristics.(4)

Feature (1 point each) Measurement

Points

Cognitive impairment MMSE 1
Acute illness APACHE >16 1
Visual impairment Corrected >20/70 1
Dehydration Urea nitrogen:creatinine 18 1

The points are added. The incidence of delirium in
patients scoring 0 points is 3-9%, 1-2 points is 16-23%, and for
3 points is 32-83%.
MMSE, Mini Mental State Examination; APACHE, Acute Physiology, Age,
and Chronic Health Evaluation.

Figure

Figure. The Confusion
Assessment Method (CAM) for the diagnosis of delirium. Diagnosis of
delirium using the CAM requires the presence of both features 1 and
2, and either feature 3 or 4.