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)

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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

References

Oh's Intensive Care manualChapter 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.