Delirium

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Contents 1 Introduction 2 Etiology 3 Epidemiology 4 Pathology 5 Clinical-manifestations 6 Laboratory 7 Diagnostic-procedures 8 Radiology 9 Complications 10 Differential-diagnosis 11 Management 12 More General Terms 13 Additional Terms 14 References

Introduction

• A confusional state. (from the Latin de-lira 'off the path')

Etiology

• D - drugs*, dehydration
• E - electrolyte imbalances*, environment, endocrine*
• L - liver disease ( encephalopathy), lungs ( hypoxia)
• I - infection*, immune dysfunction, intracranial lesions
• R - retention, restraint
• I - ischemia*, intoxication, intestinal obstruction
• U - uremia
• M - myocardial disease*, metabolic abnormalities
  

• Drugs & toxins: (see drugs commonly producing delirium)

• Endocrine:

• hypothyroidism, adrenal crisis, diabetic ketoacidosis, hypoglycemia

• Electrolytes:

• hyponatremia, hypocalcemia, hypercalcemia

• Infection:

• especially urinary tract infection & pneumonia

• Ischemia:

• cerebral or cardiac ischemia, seizures

• Retention ( urinary retention or fecal { constipation})
• Restraints & other tethers: IV lines, catheters, ECG leads
• Myocardial disease:

• myocardial infarction, arrhythmia, congestive heart failure

• Metabolic abnormalities:

• vitamin deficiencies ( vitamin B12, vitamin B3, thiamine)
  

• see risk factors for delirium
• see drugs commonly producing delirium

Epidemiology

• 20-50% of hospitalized elderly patients

• most common contributor to excess length of hospitalization [5]
• 75-90% of hospitalized patients with dementia [6]

• often unrecognized

• fluctuating symptoms
• often attributed to dementia or psychiatric disorder

• baseline assessment facilitates recognition

• may persist for months without correction of underlying cause

Pathology

• relative cholinergic deficiency & dopaminergic excess
• glucocorticoids may play a role
• cognitive impairment, dehydration, hypoxia, infection, immobility, pain, poor nutrition, medication overuse, visual impairment, hearing impairment, & sleep deprivation contribute [18]

Clinical-manifestations

• rapid onset (develops over hours to days) [6]
• fluctuating with nocturnal exacerbation

• 'sundowning'
• alteration in the sleep-wake cycle

• reduced level of consciousness
• inattention (distinguishing feature of delirium)
• impaired cognition

• disorganized thinking
• learning & memory impairment (recent & remote)

• perceptual disturbances

• hallucinations, visual > auditory

• psychosis & agitation

• delusions, generally paranoid & persecutional
• fleeting & poorly systematized thought processes

• impaired orientation
• disorders of affect

• emotional lability
• anxiety, depression, fear

• personality changes
• often incoherent speech; dysarthria may contribute
• unpredictable psychomotor activity
• asterixis, coarse tremor or myoclonus
• underlying disease or drug toxicity
• autonomic dysfunction

• tachycardia or bradycardia
• hypertension or hypotension
• flushing or pallor
• impairment of pupillary function
• abnormal control of sweating

• delirium may persist more that 6 months [3,7,8,9]
• confusion assessment method is the best beside measure [16]

Laboratory

• screening tests

• chemistries:

• electrolytes, serum glucose, renal function tests
• serum Mg+2, serum Ca+2, serum phosphate
• liver function tests, plasma NH3, serum albumin
• thyroid function tests
• serum vitamin B12, serum folate

• hematology:

• complete blood count ( CBC) & differential
• coagulation studies, PT, PTT
• arterial blood gas ( ABG)
• serum CRP or ESR

• urinalysis & urine toxicology screen
• blood alcohol
• toxicology for ingested drugs
• therapeutic drug monitoring as indicated
• HIV testing

• additional testing as indicated

• lumbar puncture with CSF analysis
• heavy metal screen

Diagnostic-procedures

• electrocardiogram ( EKG)
• electroencephalogram

• generally, slowing or low- voltage activity
• triphasic waves may suggest hepatic disease
• periodic lateralizing epileptiform discharges suggest CNS infection

Radiology

• chest X-ray
• computed tomography or magnetic resonance imaging of the head

Complications

• increased length of hospital stay [10]
• increased mortality [11,17] (HR=1.71)
• increased time spent on the ventilator, leading to increased incidence of ventilator associated pneumonia
• increased rate of subsequent institutionalization (HR=2.41) [17]
• delirium accelerates cognitive decline in patients with Alzheimer's disease
• 10-fold increased risk of cognitive impairment at hospital discharge (HR=12.52) [17]

• increased risk of dementia (HR=12.52)
  

• disease interaction(s) of delirium with urinary incontinence
• disease interaction(s) of delirium with Alzheimer's disease

Differential-diagnosis

• dementia
• psychosis
• transient global amnesia
• aphasia
• visual hallucinations due to structural lesions in the occipital lobes or cerebral peduncles
• depression
• sudden onset suggests cerebrovascular disease or seizure

Management

• supportive care
• correction of underlying precipitating factor(s)
• antidotes

• Narcan 0.1 mg/kg or 0.4-2.0 mg or more IV/ IM/ SC/ ET
• consider flumazenil

• withdrawal of non-essential medications
• restraints may actually precipitate delirium
• pharmacologic agents

• agitation not responding to non-pharmacologic measures
• antipsychotics, conventional

• Haldol* 0.5-5 mg IV/ IM/ PO every 30-60 min

• atypical antipsychotics:

• respiridone, quetiapine, olanzapine

• benzodiazepines

• lorazepam ( Ativan) 0.5-1 mg every 1-2 hours IV/ IM/ PO

• compared with placebo, neither haloperidol nor ziprasidone decreases the time that ICU patients remain alive without delirium or coma [14]

• close observation until delirium clears
• prognosis

• often leads to poor outcomes

• persistent cognitive changes in > 20% [6]

• increased risk of

• prolonged hospitalization
• loss of cognitive & functional abilities
• mortality (25-40% within 30 days) [6]

• increased risk persists for 1-2 months following in- hospital delirium
• delirium in the emergency department predicts high 6 month mortality [15]
• dementia worsens prognosis
• cognitive impairment during periods of delirium does not necessarily indicate dementia

• patient education after delirium clears

• avoidance of precipitating factors
• disease-specific information

• prevention - target risk factors [5]

• cognitive impairment
• sleep deprivation
• immobility
• visual impairment ( eyeglasses)
• hearing impairment ( hearing aids, earwax removal)
• orientation: calendar, clock, name of facility visible
• dehydration
• postoperative: keep hematocrit >= 30%

• * drug of choice in hospitalized elderly [5]

More General Terms

• altered mental status (AMS)
• mental disorder

Additional Terms

• confusion assessment method (CAM)
• dementia vs delirium vs depression
• diagnostic criteria for delirium (DSM III,IV)
• drugs commonly producing delirium
• metabolic encephalopathy; toxic encephalopathy
• prevention of delirium
• risk factors for delirium

References

1. Harrison's Principles of Internal Medicine, 13th ed. Companion Handbook, Isselbacher et al (eds), McGraw-Hill Inc. NY, 1995, pg 829-39
2. Saunders Manual of Medical Practice, Rakel (ed), WB Saunders, Philadelphia, 1996, pg 1025-27
3. Medical Knowledge Self Assessment Program (MKSAP) 11, 14, 15, American College of Physicians, Philadelphia 1998, 2006, 2009
4. Fong TG, Tulebaev SR, Inouye SK. Delirium in elderly adults: diagnosis, prevention and treatment. Nat Rev Neurol. 2009 Apr;5(4):210-20. Review. PMID: [1]
5. Geriatrics Review Syllabus, American Geriatrics Society, 5th edition, 2002-2004; 7th edition 2010
6. Mahler ME, In: Intensive Course in Geriatric Medicine & Board Review, Marina Del Ray, CA, Sept 29-Oct 2, 2004
7. Levkoff SE, Evans DA, Liptzin B, Cleary PD, Lipsitz LA, Wetle TT, Reilly CH, Pilgrim DM, Schor J, Rowe J. Delirium. The occurrence and persistence of symptoms among elderly hospitalized patients. Arch Intern Med. 1992 Feb;152(2):334-40. PMID: [2]
8. Rockwood K. The occurrence and duration of symptoms in elderly patients with delirium. J Gerontol. 1993 Jul;48(4):M162-6. PMID: [3]
9. Bergmann MA, Murphy KM, Kiely DK, Jones RN, Marcantonio ER. A model for management of delirious postacute care patients. J Am Geriatr Soc. 2005 Oct;53(10):1817-25. PMID: &dopt=Abstract
10. Thomason JW, Shintani A, Peterson JF, Pun BT, Jackson JC, Ely EW. Intensive care unit delirium is an independent predictor of longer hospital stay: a prospective analysis of 261 non-ventilated patients. Crit Care. 2005 Aug;9(4):R375-81. Epub 2005 Jun 1. PMID: [4]
11. Leslie DL, Zhang Y, Holford TR, Bogardus ST, Leo-Summers LS, Inouye SK. Premature death associated with delirium at 1-year follow-up. Arch Intern Med. 2005 Jul 25;165(14):1657-62. PMID: [5]
12. Fong TG et al. Delirium accelerates cognitive decline in Alzheimer disease. Neurology 2009 May 5; 72:1570. PMID: [6]
13. Brown LJE et al Cognitive visual perceptual deficits in patients with delirium. J Neurol Neurosurg Psychiatry 2009 Jun; 80:594. PMID: [7]
14. Girard TD et al. Feasibility, efficacy, and safety of antipsychotics for intensive care unit delirium: The MIND randomized, placebo- controlled trial. Crit Care Med 2010 Feb; 38:428. PMID: [8]
15. Han JH et al. Delirium in the emergency department: An independent predictor of death within 6 months. Ann Emerg Med 2010 Sep; 56:244. PMID: [9]
16. Wong CL et al. Does this patient have delirium? Value of bedside instruments. JAMA 2010 Aug 18; 304:779. PMID: [10]
17. Witlox J, Eurelings LS, de Jonghe JF, et al. Delirium in elderly patients and the risk of postdischarge mortality, institutionalization, and dementia: a meta-analysis. JAMA 2010 Jul 28; 304(4):443-451. PMID: [11]
18. O'Mahony R et al. Synopsis of the National Institute for Health and Clinical Excellence guideline for prevention of delirium. Ann Intern Med 2011 Jun 7; 154:746. PMID: [12]
19. National Guideline Clearinghouse
    - (1) Caregiving strategies for older adults with delirium, dementia and depression. (2) Caregiving strategies for older adults with delirium, dementia and depression 2010 supplement. Registered Nurses' Association of Ontario (RNAO) ngc-guideline: [13]
    - Delirium: prevention, early recognition, and treatment. In: Evidence-based geriatric nursing protocols for best practice. Hartford Institute for Geriatric Nursing ngc-guideline: [14]
    - Evidence-based practice guideline. Acute confusion/delirium University of Iowa Gerontological Nursing Interventions Research Center, Research Translation and Dissemination Core ngc-guideline: [15]
    - Delirium: diagnosis, prevention and management. National Collaborating Centre for Acute and Chronic Conditions. ngc-guideline: [16]

delirium (confusional state)