Define delirium and describe your management approach to this problem in the ICU.

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College Answer

Definition:

The acute onset of a disturbance of consciousness with inattention, changes in cognition and/orperception, that fluctuates over time, occurs as a consequence of a general medical condition and isnot better accounted for by a pre-existing, established or evolving dementia.

Management:

  1. Early recognition of delirium.
  1. Stabilise and ensure safety of the patient:
    • Attend to airway, breathing and circulation issues as required.
  1. Consider and rule out any potentially life-threatening causes of delirium (comprehensive history and physical examination will provide clues):
    • Hypoxia
    • Hypoglycaemia
    • Intra-cerebral haemorrhage
    • Meningitis/Encephalitis
    • Poisoning
    • Wernicke’s Encephalopathy
    • Infection: local (wound, anastomotic leaks etc.), UTI, lung etc.
    • Withdrawal from drugs
    • Hypertensive encephalopathy
    • Metabolic derangements – sodium, renal, liver.
  1. Consider non-pharmacological strategies to control symptoms:
    • Application of hearing aids, spectacles and dentures if worn.
    • Continuous re-orientation of patient - verbal, visual with photographs etc.
    • Enlist help of family members and/or interpreters.
    • Ensure as close to normal as possible sleep/wake cycles in a quiet and calm environment.
    • Treat pain, constipation, urinary retention if present.
    • Check drug chart and beware/attend to poly-pharmacy and cessation of drugs associated with delirium.
    • Mobilise early.
    • Avoid physical restraints if safe to do so.
  1. Obtain pharmacological control of symptoms if necessary:
    • Anti-psychotics are first line agents e.g. haloperidol, olanzepine, quetiapine.
    • Haloperidol 1-5mg iv q30 PRN. Dose can be doubled and repeated. Beware long QTc.
    • Benzodiazepines as first line agents for alcohol withdrawal only. Often used in combination with anti-psychotics in difficult to control symptoms in non-alcohol withdrawal delirium.
  1. Treat cause if found:
  2. O2, antibiotics, thiamine, glucose, electrolyte replacement, intra-venous fluids if dehydrated.

13

Investigations:

Directed by history, physical examination and differential diagnosis but include/consider;

Basic:

FBC, EUC, Glucose, LFT, ABG, CXR, ECG, Urinalysis + Dipstick, Septic screen, Urinary Drug Screen.

Advanced:

CT Brain, LP, TTE.

Discussion

Delirium is a favourite of the examiners. It is discussed in greater depth elsewhere ("Delirium in the ICU")

In order to simplify revision, I reproduce the salient points here:

The DSM -V diagnostic criteria for delirium:

  • Disturbance in attention and awareness.
  • Change in cognition
  • The disturbance develops over a short period and tends to fluctuate
  • 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.

A systematic approach to this question would resemble the following:

Urgently exclude and manage any lifethreatening aetiologies of delirium:

A) - Look for airway compromise due to decreased level of consciousness

B) - Assess for hypoxia and hypercapnea

C) - Assess for hypotension (thus cortial hypoperfusion) or hypertension (thus, hypertensive encephalopathy)

D) - Exclude hypoglycaemia and intoxication or poisoning; investigate for focal intracranial causes of delirium, such as intracranial haemorrhage or space-occupying lesion. Think about non-convulsive status epilepticus as the cause of delirium. Also consider withdrawal from alcohol and other drugs.

E) - Evaluate electrolytess, looking for hyponatremia

F) - Assess renal function, looking for uremia and dehydration

G) - Assess hepatic function, suspecting hepatic encephalopathy. Don't forget Wernicke's.

H) - Assess bone marrow function - cytopenia may be a clue to a space-occupying metastatic lesion, whereas blood film findings such as macrocytosis may suggest a chronic nutritional deficiency associated with alcoholism or IV drug abuse.

I) - Assess temperature, inflammatory markers and features of sepsis, ranging from UTI to septic shock (thinking about septic encephalopathy). Consider neurosyphilis and think about meningitis or encephalitis.

Investigation of delirium:

Stemming from the abovementioned differentials,

  • ABG
  • Urinalysis
  • EUC
  • CMP
  • FBC
  • Blood film
  • Inflammatory markers
  • CT brain
  • EEG
  • Lumbar puncture

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 IDCs

Pharmacological:

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

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.

Ely, E. Wesley, et al. "Evaluation of delirium in critically ill patients: validation of the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU)."Critical care medicine 29.7 (2001): 1370-1379.

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Moots, R. J., et al. "Old drug, new tricks: haloperidol inhibits secretion of proinflammatory cytokines." Annals of the rheumatic diseases 58.9 (1999): 585-587.

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Kim, Sung‐Wan, et al. "Risperidone versus olanzapine for the treatment of delirium." Human Psychopharmacology: Clinical and Experimental 25.4 (2010): 298-302.

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