Delirium

“Acute or subacute brain failure in which impairment of attention is accompanied by abnormalities of perception and mood”

Risk Factors

• Disease – Dementia, constipation, pneumonia, UTI
• Post-surgical complications – medication e.g. benzodiazepines
• Altered metabolic homeostasis
  Extremes of age
• Injured brain – previous head injury, alcohol brain damage, previous stroke
• Dislocation to an unfamiliar environment e.g. hospital admission
• Sleep deprivation
• Sensory extremes
• Immobilization

Aetiology

• Systemic infection – particularly with high fever
• Metabolic disturbance – hepatic failure, CKD, dehydration, hypoxia
• Vitamin deficiency – thiamine, nicotinic acid, B12
• Endocrine disease – hypothyroidism, Cushing syndrome
• Intracranial causes – trauma, tumours, abscess, subarachnoid haemorrhage, epilepsy
• Drug intoxication – anticonvulsants, antimuscarinics, anxiolytics, TCAs, dopamine agonists, digoxin
• Drug/alcohol withdrawal

Pathophysiology

• Poorly understood

Clinical Presentation

• Difficulties with attention span, concentration, remaining conscious
• The patient usually has a reversed sleep cycle i.e. awake in the night, sleeps in the day
• Disorganised or delayed thinking
• Can present as hypoactive or hyperactive symptoms
  • HYPERactive: agitated, aggressive, delusions/hallucinations (tactile/visual)
  • HYPOactive: drowsy, less reactive, withdrawn

• “DELIRIUM”
  • Disordered thinking
  • Euphoric/fearful/depressed/angry
  • Language impaired
  • Illusions/delusions/hallucinations
  • Reversal of sleep/wake cycle
  • Inattention
  • Unaware/disoriented
  • Memory deficits

Investigations

• Find the cause!

• Bloods:
  • FBC
  • U + Es
  • LFTs
  • Blood glucose
  • ABG
  • Septic screen
  • Malaria films
• Imaging:
  • ECG
  • CT/MRI
• Special:
  • LP
  • EEG

• Diagnostic criteria
  • Disturbance of consciousness
  • Change in cognition
  • Develops in hours to days
  • Fluctuation over the course of the day

Management

• Treat underlying cause.
• General management:
  • Nurse in moderately lit, quiet room and aim to reduce confusion as much as possible (e.g. same staff, ensure the patient has hearing/visual aids if necessary, place clock in the room to ensure they are oriented with time)
  • Try to get patient to care for themselves
  • Minimize sedatives

Complications

• Brain recovery usually lags behind recovery from the physical illness

Differentials

• Anxiety
• Primary mental illness (e.g. schizophrenia)
• Dementia