Psychological medicine

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