Delirium

• Global and transient disturbances of consciousness, attention, perception, thinking, memory, psychomotor behaviour, emotion and sleep-wake cycle
• = Acute Confusional State
• Epidemiology:
  • Rare in the community
  • Common in hospital, especially in elderly, 10 – 25% of > 65 years olds admitted to medical wards
  • Significant mortality: approx 25% of elderly patient acquiring delirium in hospital die
• Will get poor history from the patient.  Need informant

Symptoms

• Rapid onset (potentially related to new illness/drug).  Rarely lasts more than several weeks
• Fluctuating consciousness (cf psychiatric illness, which does not present with impaired consciousness)
• Marked abnormalities of attention and concentration
  • Attention unfocused
  • Thinking: disorganised, delusions, rambling incoherent speech
  • Memory impairment
• Perception: illusions and hallucinations (especially visual)
• Psychomotor behaviour: over/under active, purposeless
• Mood: labile, agitation, fear, anxiety
• Sleep-wake cycle: disrupted or even reversed

Aetiology

• Common causes: Often multi-factorial – a little bit of a number of things
  • Infection: UTI, pneumonia
  • Drug reactions
  • Hypoglycaemia 
  • ¯O2 or ­CO2

• Comprehensive list: 
  • Drugs: antiarrhythmics, antibiotics, anti-virals, anti-fungals, b-blockers, etc. etc
  • Drugs of abuse
  • Withdrawal: alcohol, amphetamines, barbiturates, benzos, cocaine 
  • Neurologic: stroke, epilepsy, Parkinson‟s, Huntington‟s, MS, Tumour, normal pressure hydrocephalus (confusion, incontinence, gait disturbance) 
  • Endocrine: Hyper/hypothyroidism, hyper/hypoPTH, Hyper/hypoadrenocorticolism, diabetes mellitus, phaeochromocytoma, etc 
  • Metabolic: hyponatraemia, hypokalaemia, hyper/hypocalcaemia, acidosis, hypoxia, uraemia, porphyria
  • Vitamin deficiencies: thiamine, folate, B12 
  • Infection: Especially chest and urinary tract, also sepsis, meningitis, encephalitis, AIDS, Hepatitis, etc 
  • Other: lung/pancreatic cancer, paraneoplastic syndromes, SLE, etc

• Differential of acute confusion:
  • Psych illness: delirium, psychosis, dementia, depression 
  • Drugs, illness, metabolic, trauma, hypoxia, poisoning/overdose, post-ictal, ¯thiamine

Risk factors

• Multiple, severe or unstable medical problems
• Dementia or cognitive impairment
• Polypharmacy
• Metabolic disturbances
• Advanced age (especially > 80 years)
• Infection (especially UTI)
• Fractures
• Visual impairment
• Fever or hypothermia
• Psychoactive drug use

Treatment

• First, recognise the delirium (it often isn‟t). Careful and repeated assessment. Watch for confused/disorientated behaviour or inattention, especially at night
• Examination:
  • Mini-mental
  • Temperature, hydration, ketosis, foetor
  • Signs of injury, including scalp
  • Infection screen
  • Neuro exam
  • Signs of drug abuse

• Investigations:
  • Bloods: FBC, ESR, U&E, Glucose, Ca, Renal, Liver, Thyroid, Thiamine
  • Urine, ECG, CXR
  • Consider: blood alcohol, cardiac enzymes, blood culture, ABG, B12/folate, CT

• Treatment of underlying cause: may require history from care giver

• Management of delirium:
  • Supportive:
    • Reorientation (a smoke and a cup of tea works wonders!)
    • Reassurance
    • Attention to noise and light levels (not too much nor too little)
    • Stimulate during the day: get up and dressed, put on glasses and hearing aid
    • Continuity of staffing
    • Family member (or even an orderly) to sit with patient
    • Familiar objects (eg family photos) in the room
    • Stimulate during the day: get them dressed, false teeth in, glasses on, hearing aid in
  • Attention to nutrition and hydration 
  • Target risk factors of cognitive impairment, sleep deprivation, immobility, visual and hearing impairment
  • Drugs: only in addition to the above, and usually to treat those caring for the patient!

• Haloperidol 0.5 mg bd (iv if possible): low dose (eg 0.5 – 1.5 mg), especially in elderly, absolute max 2 – 5 mg prn 1 – 2 hourly. Doesn‟t have anticholinergic side effects, but may cause restlessness. Maori and Pacific Islanders may be more sensitive so lower dose initially

• Lorazepam (short acting benzo) 0.5 – 2 mg q 15 – 20 min iv/im/sublingual/po