Question 12

With respect to delirium in critically ill patients:

a) Define delirium. (20% marks)

b) List the causes and predisposing factors. (30% marks)

c) Briefly outline its assessment and treatment. (50% marks)

[Click here to toggle visibility of the answers]

College answer

a) Definition: 
The acute onset of a disturbance of consciousness with inattention, changes in cognition and/or perception, that fluctuates over time, occurs as a consequence of a general medical condition and is not better accounted for by a pre-existing, established or evolving dementia. 

b) Causes / Predisposing factors:

  • Age >80
  • Pre-existing cognitive impairment
  • Severity of illness
  • Visual impairment
  • Dehydration
  • Infection/Fever/Hypothermia
  • Hypoxia
  • Drugs/Polypharmacy o Esp Psychoactive drugs o Anticholinergics,  o Narcotics o Steroids
  • Drug withdrawal  o Etoh, Benzos, SSRI
  • Metabolic shifts- [Na], renal failure, BSL, Wernickes
  • Cardiorespiratory disease
  • Sensory deprivation, overstimulation
  • Trauma/Post op o Esp – Cardiac sx, Cataract sx, Orthopedics and TURP   

 c) Assessment:

  • DSM V
  • CAM, CAM ICU
  • Memorial delirium assessment scale

d) Treatment

  • High-level supportive care 
  • Sleep hygiene
  • Hydration
  • nutrition- thiamine
  • Early mobilization
  • Avoid physical restraints
  • Visual and hearing aids
  • Minimize staff changes and utilize family members
  • Frequent reorientation
  • Do not directly engage or oppose hallucinations/ paranoid behaviours
  • Treat underlying cause and precipitant
  • Treat psychotic phenomenology
  • Haloperidol
  •  Risperidone
  • Olanzapine
  • Dexmetomidine 

Additional Examiners Comments
In general, well answered.

Discussion

This question closely resembles Question 29 from the second paper of 2009. It also features a positive comment from the examiners, which is unprecedented.

a) Definition of delirium (the DSM V definition)

  • Disturbance in attention (ie, reduced ability to direct, focus, sustain, and shift attention) and awareness.
  • Change in cognition (eg, memory deficit, disorientation, language disturbance, perceptual disturbance) that is not better accounted for by a preexisting, established, or evolving dementia.
  • The disturbance develops over a short period (usually hours to days) and tends to fluctuate during the course of the day.
  • There is evidence from the history, physical examination, or laboratory findings that the disturbance is caused by a direct physiologic consequence of a general medical condition, an intoxicating substance, medication use, or more than one cause.

b) Risk factors:

Risk Factors Associated With Delirium

Significant risk factors:
  • Pre-existing dementia
  • Hypertension
  • Alcoholism
  • High severity of illness at admission
Preventable risk factors
  • Urinary catheters
  • Use of restraints
  • Opiates (especially morphine)
  • Benzodiazepines
  • Polypharmacy
  • Anticholinergic drugs
Associated factors
Uncontrollable risk factors
  • Age over 65
  • Depression
  • Nursing home placement
  • Coma of any cause
  • Sepsis
  • Renal failure
  • Hepatic failure
  • Pre-existing respiratory disease
Modifiable risk factors
  • Sleep deprivation
  • Pain
  • Dehydration
  • Constipation
  • High bilirubin
  • Uraemia
  • Hypo/hypernatremia
  • Hypo/hypercalcemia
  • Immobility
  • Hypercapnea
  • Hypoxia
  • Hypotension
  • Anaemia
  • Acidosis

c) Management of delirium

Non-pharmacological:

  • Good analgesia
  • Clear and firm communication with the patient
  • Frequent re-orientation
  • Family presence
  • Low-noise environment
  • Restoration of hearing aids and spectacles
  • Avoidance of sleep disturbance, promotion of normal sleep–wake cycle.
  • Avoidance of physical restraints
  • Early removal of IV lines and IDC
  • Early mobilisation
  • Adequate hydration
  • Adequate (oral) nutrition
  • Use of thiamine

Pharmacological:

  • Dexmedetomidine
  • Atypical antipsychotics
  • Classical antipsychotics
  • Benzodiazepines (if withdrawing from alcohol or benzodiazepines)

References

Oh's Intensive Care manual: Chapter 49   (pp. 549) Disorders  of  consciousness  by Balasubramanian  Venkatesh

Girard, Timothy D., Pratik P. Pandharipande, and E. Wesley Ely. "Delirium in the intensive care unit." Critical Care 12.Suppl 3 (2008): S3.

Barr, Juliana, et al. "Clinical practice guidelines for the management of pain, agitation, and delirium in adult patients in the intensive care unit." Critical care medicine 41.1 (2013): 263-306.

Ouimet, Sébastien, et al. "Incidence, risk factors and consequences of ICU delirium." Intensive care medicine 33.1 (2007): 66-73.

Van Rompaey, Bart, et al. "Risk factors for intensive care delirium: a systematic review." Intensive and Critical Care Nursing 24.2 (2008): 98-107.

Schweickert, William D., et al. "Early physical and occupational therapy in mechanically ventilated, critically ill patients: a randomised controlled trial."Lancet (London, England) 373.9678 (2009): 1874-1882.

Inouye, Sharon K., et al. "A multicomponent intervention to prevent delirium in hospitalized older patients." New England journal of medicine 340.9 (1999): 669-676.