Delirium

This is an acute confusional state which is characterised by rapid onset of a global but fluctuating dysfunction of the CNS due to a variety of insults on the brain.

– It is more commonly seen in people aged >65 and those with diffuse brain disease (dementia)

– However, it can be experienced by anyone in hospital and is an important thing to keep watch out for

Causes – The main causes can be remembered using the acronym PINCH-ME:

M – Medication (drugs)

E – Electrolytes (e.g. hyponatraemia)

E – Environment

Symptoms – Delirium is usually divided into 3 main subtypes:

• Hypoactive

This is a type of delirium where the patient will be very withdrawn, quiet and sleepy

– They might display inactive or reduced motor activities or seem to be in a daze

• Hyperactive

This is a type where patients will be restless, agitated and may display aggressive behaviour

– They may exhibit strong emotions with fearfulness and hallucinations and be uncooperative

• Mixed

In this situation, the patient will display signs of hypo- and hyperactive delirium

Other symptoms:

– Poorly explained, transient delusions –> often persecutory with associated ideas of reference

– Autonomic overactivity –> causes sweating, tachycardia and dilated pupils

– Disturbance of sleep-wake cycle –> patient more alert during evening and drowsy during the day.

Diagnosis: To be diagnosed with delirium, patients must satisfy different criteria:

1) Impaired Attention and Awareness

2a) Perceptual Disturbance (e.g. visual illusions/hallucinations) or 2b) Cognitive disturbance (e.g. memory/orientation deficit)

3) Symptoms should develop over a short period of time and fluctuate during day

4) Not due to a pre-existing psychiatric disorder

Assessment – Take a full history

– Mental State Examination to confirm diagnosis

– MOCA (cognitive assessment)

– Physical Examination to find any underlying cause

Investigations:

– Blood test (FBC, U&E, folate, Vit B₁₂, Ca²⁺)

– Blood cultures –> to rule out infection

– Urinalysis –> to rule out UTI

– ECG and CXR

– CT head/MRI

Management – Treat underlying cause and correct electrolyte and fluid imbalances

– Aim to make the environment as comfortable as possible and the doctors/nursing team the same

– Sedatives include short acting benzodiazepine (lorazepam) and promethazine 25-50mg

– Can also use antipsychotics like haloperidol/risperidone

N.B. It is important to be able to distinguish between delirium and dementia. Here are the main differences: