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Delirium
Delirium

Delirium

Delirium is an acute confusional state in which one’s mental status acutely fluctuates with inattention, disorganised thinking, and altered consciousness due to an underlying cause. It is a common presentation, but is potentially life-threatening.

Although delirium may occur in the community, it is also common for delirium to develop in the inpatient setting.

📝 Criteria

The DSM-V criteria for delirium states that for an individual to be diagnosed with delirium, they need to present with all 4 of the following:

  1. Disturbance in attention and awareness - the patient is unable to direct their focus and constantly shift attention. They have reduced orientation to their environment also.
  2. Acute development - hours to a few days with a fluctuating course.
  3. Disturbance in cognition - that is not accounted for by pre-existing dementia.
  4. Occurs as a direct physiological consequence of physical condition, substance intoxication or substance withdrawal
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⚠️ Risk factors and causes

  • Long inpatient hospital stays or long-term care home stays
  • Old age (>65 years old)
  • Dementia - dementia increases risk of delirium but conversely delirium increases the risk of dementia.
  • Previous cognitive impairment
  • Hip fracture
  • Acute illness
  • Psychological agitation such as being in pain.

As we mentioned, delirium has an underlying aetiology. Some conditions that cause delirium can be summed up with the mnemonic CHIMPS PHONED V:

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CHIMPS PHONED V:

C - Constipation

H - Hypoxia

I - Infection: UTI and pneumonia most frequently. Malaria, wound infection and intracranial infections may cause delirium too.

M - Metabolic disturbance: liver failure, renal failure, hyper/hyponatraemia, hyper/hypoglycaemia, anaemia.

P - Pain

S - Sleeplessness

P - Post-operatively/post general anaesthesia

H - Hypothermia/pyrexia

O - Organ dysfunction

N - Nutrition: thiamine deficiency (Beriberi), B12 deficiency, nicotinic acid deficiencies.

E - Environmental changes

D - Drugs and drug withdrawal

V - Vascular issues: stroke and MI

🔢 Classification

We can subdivide delirium into 3 different types:

Hyperactive delirium

Patient will be restless, agitated, aggressive, hallucinating, aroused and will display inappropriate behaviour.

Hypoactive delirium

Patient will be lethargic, slow, have incoherent speech and seem withdrawn.

Mixed delirium

Will show both hypoactive and hyperactive signs.

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Both mixed and hypoactive delirium can be difficult to recognise and are under-diagnosed as a result.

🔍 Investigations

Delirium is predominantly diagnosed based off of clinical diagnosis.

What are some things to assess to support this clinical diagnosis?

  1. Patient history - it is essential to understand the medical history of the patient, looking at transfer papers from other institutions. Speaking to family/caregivers can establish a baseline cognitive status which is useful and necessary to make a diagnosis.
  2. Delirium screening tools - the Confusion Assessment Method (CAM) and Confusion Assessment Method for ICU (CAM-ICU). Abbreviated Mental Test Scores (AMTS) is also used (we will discuss this further below).
  3. Medication review
  4. Systems review
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Additional investigations for delirium:
  • Blood tests - FBCs, TFTs, LFTs, U&Es, glucose, ABG, blood cultures.
  • Urinalysis - a positive dipsticks without clinical signs is not sufficient to diagnose UTI as the cause of delirium.
  • Imaging - CXR or CT head is recommended if assessing for head/lung pathology.
  • ECG - to exclude MI.
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AMTS questions

10 questions to be asked. A score of <6 is suggestive of delirium or dementia.

  1. What is your age?
  2. What is the time to the nearest hour?
  3. Give the patient an address and ask them to repeat it at the end of the test.
  4. What is the year?
  5. What is the name of this location? OR what is your house number?
  6. Can the patient recognise 2 people?
  7. What is your DOB?
  8. What year did world war 1 begin?
  9. Name the current monarch/prime minister/president.
  10. Count backwards from 20 → 1.

Management

The only definitive management is identification and management of the underlying cause.

We can also provide supportive care and medical care for the patient:

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Supportive management:
  1. Reorientation - inform the patient of where they are, who they are and what has happened.
  2. Encourage visits - from friends and family.
  3. Monitor fluid balance - be sure to look out for constipation.

Delirium may persist for weeks after the original illness.

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Medical management:

Review the medication of the patient and discontinue any unnecessary treatments.

🥇 Haloperidol may be given 1st line if the patient is a risk to their own/someone else’s safety.

💭 Differential diagnosis

  • Dementia
  • Anxiety
  • Epilepsy - specifically non-conclusive status epilepticus.
  • Underlying causes (CHIMPS PHONED V)
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DEMENTIA VS. DELIRIUM

Delirium usually has some factors in favour, such as:

  • Impaired consciousness
  • Fluctuating symptoms - worsening at night usually, with periods of normality.
  • Abnormal perception
  • Agitation and fear
  • Delusions

Patients may seem out of this world and tend to wander around.