Delirium
Thomas Bartuska, M.D.
Delirium is one of the
most common conditions seen in the inpatient setting, believed
to affect 10-15% of inpatients. The etiology of the syndrome is
often multifactorial and it is under-diagnosed, yet delirium is
a medical emergency associated with high mortality if left untreated.
Delirium is
- a transient disorder
of global cognitive function that is acute or sub-acute in onset.
- characterized by an
alteration in sensorium (level of consciousness) and abnormal
response to environmental stimuli (either lethargy or agitation)
often with hallucinations, misperceptions and paranoia.
- manifest by disorientation
to time, place and, in more severe cases, person.
- noted to have a fluctuating
pattern over the course of the day and is often worse at night
(sun-downing).
- distinguished from dementia,
which is chronic and not characterized by alterations in sensorium.
The two syndromes often co-exist because dementia is a risk factor
for development of delirium.
- always caused by an
underlying medical condition that must be treated before cognition
can improve.
Risk Factors
- advanced age
- sensory impairments
- substance abuse
- pre-existing dementia
or other CNS structural damage (i.e., stroke)
- the ICU environment
- infections
- polypharmacy
- a previous episode of
delirium
- poor functional status
- post operative status,
especially hip fracture
Evaluation
- history and physical
examination to determine duration of symptoms, drug use or other
risk factors, co-existing illnesses, new physical or neurologic
findings. Surrogate historians will be essential. Infection and
drug effects are the most common causes of delirium. Diphenhydramine
(Benadryl) and OTC medications such as cold treatments are common
causes even though they seem innocuous. Infections may present
atypically.
- Rule out life threatening
processes:
- hypoxemia
- metabolic disorders
- cardiovascular abnormalities
- (MI/arrhythmias, hypotension)
- intracranial events
Laboratory
- electrolytes, calcium, magnesium,
phosphorus, CBC, BUN&Cr, glucose, ABG, urinalysis, medication
levels, ECG, and thyroid function tests.
- Toxicology screen for alcohol,
drugs and poisons.
- Head CT has not been shown
to contribute to evaluation of delirium in the absence of focal
findings or history of head trauma.
- If clinically indicated: lumbar
puncture, EEG, appropriate cultures, HIV titer.
- B12, Folate, and VDRL - the
syndromes associated with abnormal values cause chronic cognitive
deficit. These tests have no place in the evaluation of acute
mental status changes.
Management
- Provide supportive care as
urgently required.
- Identify and treat underlying
condition.
- Treat agitation to protect
patient and staff safety.
- Minimize stimulation and use
a sitter (a calm family or staff member) to provide frequent
reorientation, simple explanations and soothing encouragement.
This will decrease need for medication or restraints. Restraints
can actually cause injury. Consult nursing staff on safe use
of restraints.
When medication is
required to control agitation in delirium
- Haloperidol (Haldol) is the
drug of choice because it has minimal anticholinergic effects
and is least likely to cause cardiovascular or respiratory compromise.
- In younger adults, a dose
of 2-10mg is appropriate but the dose in older adults should
be much lower, i.e., 0.5 mg repeated if necessary. Increased
total body fat in older adults makes this fat soluble medication
exhibit slower onset, wider volume of distribution, increased
concentration in brain, slower clearance and prolonged effects
(both good and bad).
- Anticipate agitation and treat
with scheduled, low, oral doses rather than risk over-sedation,
extrapyramidal or other negative side effects with PRN, high,
parenteral doses.
- Most patients can be maintained
at 0.5-1.0mg BID orally.
- Have a high index of suspicion
for alcohol or sedative withdrawal for which benzodiazepines
are the drug of choice.
Managing delirious patients
can be quite complicated. It may be advisable to obtain geriatrics
or psychiatry consultation.
