Delirium
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Introduction
"Little red pill" (ink/acrylic) by Michelle Micuda
Delirium is a disturbance in consciousness, along with a change in cognition (memory, disorientation, language disturbance), due to a general medical condition. It is very common, underdiagnosed, and can have a significant impact of health of the patient and the comfort of everyone involved, especially family and caregivers.
Delirium is distinguished from other changes in mental status such as dementia by it's occurrence over a short period of time (hours to days), and its tendency to fluctuate.
Symptoms tend to be present from each of the following categories:
- consciousness and attention
- cognition (illusions and hallucinations, impaired thinking and comprehension, inhcoherence)
- psychomotor (hypo- or hyperreactivity, increased reaction time, increased or decreased speech)
- sleep disturbance (wake cycle disruption, daytime drowsiness, nocturnal worsening of symptoms, disturbing dreams or nightmares)
- emotional (depression, anxiety, irritability, euphoria, apathy, perplexity)
The Case of Ms. Dewar
Ms. Dewar is an 86 year-old woman admitted to the hospital with a hip fracture. Post-operative day two, her nurse nitces she is agitated, yelling at her roommates and attempting to climb out of her bed.
- how would you diagnose delirium?
- what investigations would you order?
- how would you treat her symptoms?
Causes and Risk Factors
Infection and medications are most common causes of delirium.
Medications:
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Organ failure
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Infection:
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Acute metabolic disorder:
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Other
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Risk factors for developng delirium include:
- hospitalization (incidence 10-40%), major surgery, ICU stay
- nursing home residents (incidence 60%)
- childhood (febrile illness)
- old age (65+)
- male
- previous delirium
- multiple medications
- poor social contacts
- poor baseline vision or hearing
- poor nutrition or dehydration
- catheterization
- severe illness: cancer, AIDS
- pre-existing cognitive impairment
- recent anesthesia
- substance abuse
Pathophysiology
There is no pathophysiologic explanation for delirium, though it likely results from interplay between acute illness and cognitive frailty. There is usually some global cortical dysfunction.
Theories:
- increased anticholinergic activity
- decreased cerebral blood flow
- altered BBB function
Signs and Symptoms
Disturbance in consciousness can include reduced clarity of awareness of the environment, with reduced ability to focus, sustain, or shift attention. These disturbances develop over a short time (usually hours to days) and tend to fluctuate over the course of a day. This is in contrast to dementia, which shows an irreversible decline over time.
Upon history, physical exam, or lab findings, direct physiological causes can be found.
- history
- physical exam
History
Mental Status Assessment
Change in cognition can involve a memory deficit, disorientation, or language disturbance. Perceptual disturbances, such as illusions or hallucinations, can also occur. Agitation is unfortunately quite common.
Common symptoms include:
- wandering attention
- distractibility
- disorientation (usually time and place)
- misinterpretations, illusions, hallucinations
- speech/language disturbances (dysarthria, dysnomia, dysgraphia)
- affective symptoms: anxiety, fear, depression, irritability, anger, euphoria, apathy
- shifts in psychomotor activity: groping, picking at clothes, attempts to get out of bed when unsafe, sudden movements, sluggishness, lethargy
Confusion Assessment Method (Need 1 and 2 and 3 or 4)
- Is this of acute onset and with fluctuating course?
- Does the patient have difficulty focusing attention? (easily distractible, difficulty keeping track)
- Is the patient's thinking disorganized or incoherent, rambling or irrelevant, unclear or illogical, unpredictable?
- Is the patient's consciousness hyperalert, drowsy, stuporous, or comatose?
A 2010 Meta-analysis best supports the CAM for screening (Wong et al, 2010).
Physical Exam
Investigations
- lab investigations
- diagnostic imaging
Lab Investigations
- CBC + diff
- electrolytes
- calcium (hypercalcemia)
- phosphate
- magnesium
- glucose
- ESR
- liver enzymes
- RFTs
- TSH
- vitamin B12, folate, thiamine
- albumin
- urine C&S, R&M
as indicated:
- toxicology/heavy metal screen
- VDRL, HIV, blood cultures
Diagnostic Imaging
As indicated:
- ECG
- CXR
- CT head
Do imaging if there is a focal neurological deficit, acute change in status, anticoagulant use, acute incontinence, gait abnormality, or history of cancer.
Differential Diagnosis
Treatments
The NICE has produced a set of evidence-based recommendations for the prevention and management of delirium (O'Mahony et al, 2011).
Consequences and Course
2x mortality, 7x if not detected (Siddiqi, 2006)
Up to 50% mortality rate one year after an episode of delirium.
Up to 76% mortality rates in hospitalized pts
Additional Resources
O'Mahoney R. 2011. Synopsis of the National Institute for Health and Clinical Excellence guideline for prevention of delirium. Ann Intern Med. 154(11):746-51.
Wong CL et al. 2010. Does this patient have delirium? value of bedside instruments. JAMA. 304(7):779-86.
Siddiqui. 2006 Age Aging
Inouye 2006. NEJM. 354:1157-65.
Preventing Delerium (NEJM, 1999)
Topic Development
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