General MedicineTier 1Approach to a presentation

Undifferentiated presentations - delirium

Red flags

Delirium + fever/haemodynamic instability - sepsis until excluded
Delirium + focal neurology - stroke, subdural (esp. post-fall in elderly on anticoagulation)
Delirium + hypoxia - respiratory failure, PE
Rapidly fluctuating consciousness - non-convulsive status epilepticus
New delirium in a previously high-functioning patient - always has a cause, never "just old age"

Mnemonic approach - the causes are the same regardless of setting

Infection: UTI, pneumonia, sepsis (often the commonest cause in the elderly)
Metabolic: hypo/hyperglycaemia, hyponatraemia, uraemia, hypercalcaemia, hypoxia, hypercapnia
Drugs: anticholinergics, opioids, benzodiazepines, corticosteroids, polypharmacy, alcohol/benzodiazepine withdrawal
Structural: stroke, subdural haematoma, raised ICP, non-convulsive status epilepticus
Retention/impaction: urinary retention, faecal impaction (surprisingly common precipitant)
Environmental: unfamiliar environment, sleep deprivation, sensory deprivation (missing glasses/hearing aids), pain

Acute onset and fluctuating course (vs the insidious, stable course of dementia) - collateral history essential
Baseline cognitive function
Full medication reconciliation, alcohol history
Recent falls, procedures, new symptoms (dysuria, cough, pain)

CAM (Confusion Assessment Method): acute onset + fluctuation + inattention, PLUS either disorganised thinking OR altered consciousness = delirium
Full systems examination for the precipitant - chest, abdomen (bladder, faecal loading), skin, neurological exam
Vital signs, glucose, oxygen saturation

FBE, UEC, calcium, glucose, LFT, TFT, CRP, urinalysis/MSU, blood cultures if febrile
ECG, CXR
CT brain if focal signs, recent fall/head injury, or no clear precipitant found
Review medication chart specifically for causative/contributing drugs

1. Treat the underlying cause(s) - frequently multifactorial

Correct metabolic derangement, treat infection, relieve retention/impaction, deprescribe causative drugs

2. Non-pharmacological first-line

Reorientation, familiar faces/objects, glasses/hearing aids, sleep-wake cycle optimisation, early mobilisation, adequate hydration/nutrition, minimise room changes

3. Pharmacological - reserved for severe agitation/distress/safety risk unresponsive to the above

Low-dose antipsychotic (haloperidol, olanzapine) if needed - avoid in Parkinson's/Lewy body dementia (worsens parkinsonism, neuroleptic sensitivity)
Avoid benzodiazepines except for alcohol/sedative withdrawal delirium - typically worsens confusion elsewhere

4. Communication and follow-up

Explain to family - delirium can take days-weeks to resolve, may unmask underlying cognitive impairment
Screen for underlying dementia once delirium resolves

Delirium is frequently misattributed to "just dementia" or "old age" if no collateral history establishes the acute change
Hypoactive delirium (quiet, withdrawn) is under-recognised compared to agitated delirium but equally significant
Benzodiazepines worsen most non-withdrawal delirium - a common prescribing error under time pressure
Faecal impaction and urinary retention are easily overlooked precipitants - always examine for both

1. Establish the timeline before anything else

"Acute and fluctuating means delirium until proven otherwise - I need collateral history to know the baseline."

2. Treat non-pharmacologically first

"Reorientation and correcting the cause come before any drug - antipsychotics are for safety, not routine sedation."

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