Acute confusion, otherwise known as delirium, is very common in hospitals – 20-30% on medical wards and between 10% and 50% of those that have surgery develop delirium.

Three types:
  1. Hyperactive - agitated, delusions, hallucinations, aggression
  2. Hypoactive – harder to spot - lethargy, psychomotor retardation, excessive sleeping, inattention – often misdiagnosed as depression
  3. Mixed
Predisposing factors:
  • Previous history of delirium
  • Age (>65 years) & it is more common in males
  • Dementia
    • Delirium on dementia is common. To know whether a patient may have delirium on top, you can check their AMTS against their baseline in combination with the 4AT
    • Other "geriatric syndromes": falls, elder abuse, malnutrition, polypharmacy, social isolation
  • Comorbidities
    • alcoholism
    • chronic pain
    • history of baseline lung, liver, kidney, heart or brain disease
    • terminal illness
  • Poor functional state or frailty
    • pressure ulcers
    • premorbid state
    • inactivity
Causes:
A commonly used mnemonic is PINCH ME
  • Pain
  • Infection
  • Nutrition
  • Constipation
  • Hydration
  • Medication
  • Environment
Another mnemonic is DELIRIUM
  • D- drugs, dehydration, detox (alcohol)
  • E- electrolytes (hypercalcaemia, hyponatraemia), environment (esp ICU)
  • L- lack of sleep
  • I- infection, infarction
  • R- renal failure
  • I- intoxication, impaction (constipation)
  • U- UTI
  • M- metabolic (hypoglycaemia, thyroid), malignancy (cerebral/paraneoplastic)
Investigations:
  • Guided by history and examination, collateral history is invaluable where possible
  • AMTS can be a quick confusion ‘screening test’ and repeated to show improvement – consider MMSE/ACE)
  • Observations can lead to the underlying cause (e.g. temperature suggesting infection, tachycardia - infection, dehydration or pain)
  • Bloods:
    • FBC
    • U&E
    • LFTs
    • Glucose
    • TFTs
    • Calcium
    • Haematinics
    • Blood cultures (if sepsis suspected)
  • Imaging:
    • CT head – consider in patients with no other identifiable reasons, with focal neurology, history of falls/anticoagulation, worsening or prolonged delirium, drowsiness
    • CXR – as part of infection/sepsis screen
  • Urine MC&S
    • Never reply on nitrites/leukocytes on a urine dip which will be positive in up to 50% of patients without a UTI
    • Send the urine in any patient who is delirious and consider empirical treatment (particularly if there is other evidence to support the diagnosis e.g. raised WCC, suprapubic tenderness, dysuria, frequency etc)
Management:
  • Treat the underlying cause
  • Treatment is mostly supportive:
    • Consistent team, re-orientation and reassurance, regularly introduce yourself and your role
    • Familiar objects, eg photos, books, music, clothes. Family can help with providing care which helps
    • Clear and concise communication
    • Make sure they have their hearing aids/glasses/walking stick etc
    • Try to maintain/encourage regular sleep – minimise waking through night, keeps lights off overnight etc
  • Medication
    • Avoid unless necessary such as if they are at risk to themselves or others
    • Drugs can worsen delirium. Consider stopping benzodiazepines or sedating drugs which could precipitate delirium
    • Small dose haloperidol (0.5mg) is first-line – PO or IM usually
    • Lorazepam (0.5mg) often used if contraindicated (e.g. heart issues, Parkinson's, Lewy body)
  • Time – often family/staff want delirium to be “cured” with a tablet because they don’t have the staff to constantly watch patients. 
    • Offer reassurance that delirium will settle but that this can take time, even post-discharge, and that supportive management is the best management
    • Let them know that delirium is often much better at home in a familiar environment. Keeping a patient in hospital because they are delirious sometimes can be harmful
    • Give them a leaflet
  • Always put the diagnosis of delirium on the discharge summary
    • Recurrent delirium is suggestive that the patient could be at risk of dementia, prompting closer observation and consideration of memory clinic referral
Further reading
By Emma Brooks CT1 (Psychiatry)