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.

2. Stabilise and ensure safety of the patient:

• • Attend to airway, breathing and circulation issues as required.

3. 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.

4. 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.

5. 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.

6. Treat cause if found:
7. O2, antibiotics, thiamine, glucose, electrolyte replacement, intra-venous fluids if dehydrated.

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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:

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)