Delirium — Written Clinical Reasoning

SAQ 1 — Postoperative Delirium Superimposed on Dementia (20 marks, 30 minutes)

Prompt: Outline your integrated assessment and management plan for this patient's delirium, including the precipitant search, the non-pharmacological measures, the approach to pharmacological sedation if required, the distinction from her underlying dementia, and the discussion with her husband. Justify each decision with reference to evidence and guideline recommendations. [1]

Model Answer

Problem list and framing (3 marks): [1]

This is delirium superimposed on dementia — an acute, fluctuating disturbance of attention and awareness in a patient with established Alzheimer disease, triggered by the combination of her hip fracture surgery, her medications, and the hospital environment. The framing is critical: this is not progression of her dementia (which is gradual), but an acute, potentially reversible encephalopathy that must be investigated and treated aggressively. The CAM is positive, confirming the diagnosis (Inouye 1990, PMID 2240918). The problems are: [1]

1. Acute postoperative delirium — the presenting problem, requiring a structured precipitant search and multicomponent management.
2. Mild-to-moderate Alzheimer disease — the predisposing factor that lowered her delirium threshold (dementia is the single strongest risk factor), and which influences the pharmacological choices (donepezil is a cholinesterase inhibitor — relevant to both her cognition and her bladder management).
3. Hip fracture and hemiarthroplasty — the surgical insult, a major precipitant of delirium (15 to 53 percent incidence in older postoperative hip fracture patients).
4. Polypharmacy with anticholinergic burden — oxybutynin is a potent antimuscarinic directly opposing the cholinergic mechanism of donepezil, and codeine is an opioid; both are delirium precipitants.
5. Pain control — must be adequate without exacerbating delirium.
6. Risk of falls, pressure injury, aspiration, and prolonged hospital stay — the complications of delirium that I must actively prevent.
7. Family distress and need for education — the husband needs an explanation and a role. [1]

Precipitant search — the DELIRIUM mnemonic (5 marks): [1]

I will run a structured search for all precipitants, because delirium is multifactorial and treating only one is insufficient. [1]

• D — Drugs: Oxybutynin (potent anticholinergic — I will stop it immediately; for the bladder, I would switch to mirabegron, a beta-3 agonist without anticholinergic activity, or manage with timed voiding). Codeine (I would stop it and use regular paracetamol with a regional technique such as a fascia iliaca block or local infiltration analgesia; if an opioid is needed, low-dose oxycodone or tramadol with caution). Donepezil (I will NOT stop this — cholinesterase inhibitors are protective against delirium and abrupt withdrawal can worsen cognition). Ramipril (continue — not a delirium precipitant, and important for her blood pressure and cardiovascular risk). I will review all newly added perioperative drugs (antiemetics, sedatives).
• E — Electrolytes and dehydration: Check urea, electrolytes, creatinine, calcium, glucose. She is likely postoperative and may be dehydrated from poor oral intake and fasting — I will assess hydration clinically and with biochemistry, and correct with subcutaneous or intravenous fluids if needed.
• L — Lack of drugs (withdrawal): Unlikely in this setting — no history of alcohol misuse or chronic benzodiazepine use — but I will ask the husband about her alcohol intake.
• I — Infection: Urinalysis and urine culture (catheter-associated UTI is common postoperatively), full blood count and CRP, blood cultures if febrile, chest X-ray, and a wound review. Postoperative pneumonia and urinary tract infection are the commonest infectious precipitants.
• R — Reduced sensory input: I will ensure she has her glasses and hearing aids (if she uses them), a clock and calendar she can see, a window view, and that the environment is appropriately lit during the day and quiet at night.
• I — Intracranial/CNS: Unlikely given the context (postoperative delirium is the most probable explanation), but I will perform a focused neurological examination for focal signs. If there is a history of head injury with the fall (did she hit her head, did she lose consciousness?), or if she is anticoagulated, or if focal signs emerge, I would arrange a CT brain to exclude a subdural haematoma.
• U — Urinary and faecal: Bladder scan for urinary retention (common postoperatively, especially with anticholinergics and immobility), and a rectal examination for faecal impaction (common with opioids and immobility). Both are easily missed and easily treated.
• M — Myocardial and metabolic: ECG (silent myocardial infarction is common in older diabetics — though she is not diabetic, she is hypertensive and elderly), troponin if clinically indicated, oxygen saturation (she is 96 percent on room air — adequate), and check for hypoxia, hypoglycaemia, or hypothermia. [1]

Multicomponent non-pharmacological management (4 marks): [1]

This is the mainstay and is based on the HELP programme principles (Inouye 1999, PMID 10688647). I will institute, for every shift: [1]

• Environment: A well-lit room during the day with natural light, dim and quiet at night. A clock, calendar, and orientation board. Minimise ward moves. Cluster nursing tasks overnight to protect sleep.
• Orientation: Every staff member introduces themselves and reorients her at each interaction ("Mrs X, I'm Dr Y, it is [day and date], you are in [hospital], you had hip surgery").
• Sensory aids: Ensure glasses and hearing aids are on and functioning at all times — these are frequently lost in hospital.
• Communication: Clear, simple, slow, one question at a time. Do not argue with her beliefs — acknowledge and redirect.
• Family involvement: I will ask the husband to be present as much as possible, to bring familiar objects (a family photo, a familiar blanket), and to assist with reorientation and feeding. His presence is therapeutic.
• Mobility: Early and frequent mobilisation with the physiotherapist, as her surgical repair allows. Remove the urinary catheter and intravenous line as soon as medically safe, as these tether her and reduce mobility.
• Hydration and nutrition: Active oral hydration support, assistance with meals, fluid chart, supplementary drinks. Treat dry mouth.
• Pain control: Adequate analgesia is essential — uncontrolled pain precipitates and perpetuates delirium. I will use regular paracetamol, a regional technique (fascia iliaca block) if available, and minimise systemic opioids. [1]

Pharmacological sedation — if required (3 marks): [1]

Pharmacological therapy is a last resort, reserved for severe distress or danger unresponsive to the measures above. If she is at risk of falling and injuring herself or her surgical repair, I would consider a single low dose of an antipsychotic. The choice is influenced by her Alzheimer disease (but not Parkinson disease or Lewy body disease, which would be absolute contraindications). [1]

• First-line: haloperidol 0.5 mg orally, or intramuscularly if she will not take oral, repeated after 2 to 4 hours if needed, maximum 5 mg in 24 hours. I would monitor the ECG for QT prolongation, the blood pressure, and the level of consciousness, and stop as soon as possible.
• Alternative: risperidone 0.25 to 0.5 mg orally or olanzapine 2.5 to 5 mg orally.
• Benzodiazepines are contraindicated in this setting (she is not in alcohol or benzodiazepine withdrawal) — they worsen and prolong delirium. [1]

I would counsel the husband about why we are using the medication (to settle severe distress or prevent injury, not to treat the delirium itself), the dose, the monitoring, and the plan to stop as soon as possible. The NICE CG103 guideline and the Inouye reviews (PMID 16540616, 23992774) support this cautious, lowest-effective-dose, shortest-duration approach. [1]

Distinguishing delirium from her underlying dementia (2 marks): [1]

The distinction is clinical and rests on the temporal pattern. Her Alzheimer disease is a chronic, gradual, progressive decline over three years, with a stable (though declining) day-to-day course, relatively preserved attention in the early and moderate stages, and a normal level of consciousness. The current picture — acute onset over hours confirmed by her husband ("completely different since this morning"), fluctuating course, inattention on formal testing, disorganised thinking, and altered behaviour — is delirium superimposed on the dementia. The acute change is the key: dementia does not change over hours. I would document the baseline cognition from the husband (her pre-admission MoCA of 18/30), and plan a repeat MoCA after the delirium resolves to assess whether there has been a step-down in her cognitive baseline as a result of the delirium episode (Witlox 2010, PMID 20664045, established that delirium accelerates cognitive decline in patients with dementia). [1]

Discussion with the husband (2 marks): [1]

I would explain, in plain language: "Your wife has developed delirium, which is a temporary disturbance of the brain that happens commonly after surgery in older patients, especially those who already have some memory problems. It is not a permanent loss of her mind, and it is not that her dementia has suddenly got much worse. It is caused by a combination of the surgery, the medications, the hospital stay, and possibly a minor infection or dehydration that we are looking for and treating. It usually improves over days to weeks as we treat the underlying problems and support her. I would like you to be with her as much as possible — your presence, familiar objects, and gentle reorientation help her more than you might think. In the meantime, we are stopping some of her medications that can contribute to confusion, making sure she has enough fluids and pain relief, checking for infection, and helping her to move around. If she becomes very agitated and at risk of hurting herself or her new hip, we may use a small dose of a medication to settle her temporarily, but we avoid this unless absolutely necessary." I would acknowledge the family's distress, offer written information about delirium, and arrange follow-up after discharge to reassess her cognition and function. [1]

Prognosis and follow-up (1 mark): [1]

I would set realistic expectations: most postoperative delirium resolves over 1 to 2 weeks, but a significant proportion persists at discharge, and there is an increased risk of longer-term cognitive decline and functional loss. I would plan a cognitive reassessment at 1 to 3 months post-discharge, a medication review to ensure precipitating drugs have been removed, functional rehabilitation, and a discussion about preventing recurrence (optimise vision and hearing, manage comorbidity, minimise polypharmacy, maintain activity and social engagement). [1]

SAQ 2 — Hypoactive Delirium with Multiple Precipitants (10 marks, 15 minutes)

Prompt: An 86-year-old man in a residential aged care facility is brought to the emergency department because he has become "quiet and not himself" over the last 24 hours. He is drowsy, responds slowly to questions, and sleeps whenever not stimulated. He is oriented to person only. He has a history of ischaemic heart disease, heart failure, chronic kidney disease (eGFR 35), benign prostatic hyperplasia, and depression. He takes aspirin, bisoprolol, furosemide 40 mg daily, spironolactone 25 mg daily, tamsulosin, mirtazapine 30 mg at night, and tramadol 50 mg four times daily for arthritic pain. His observations are: temperature 37.4 degrees C, pulse 62, blood pressure 96/58, respiratory rate 18, oxygen saturation 94 percent on room air. Outline your diagnostic approach to this presentation and your initial management priorities. [1]

Model Answer

Diagnostic approach — recognise and confirm hypoactive delirium (2 marks): [1]

The first task is to recognise this as hypoactive delirium, the most commonly missed subtype. The acute onset over 24 hours from his baseline (confirmed by the residential facility staff reporting he is "not himself"), the drowsiness and reduced level of consciousness, the slow responses, the disorientation, and the setting of acute illness all point to delirium. I would apply the CAM (or the 4AT) at the bedside to confirm. The trap here is to attribute the drowsiness to "he's just old" or "his depression" — the acute change is delirium until proven otherwise, and hypoactive delirium carries the worst prognosis of the subtypes, partly because it is missed and untreated. [1]

Precipitant search — the DELIRIUM mnemonic (5 marks): [1]

I will run a structured search, because this presentation almost certainly has multiple precipitants: [1]

• D — Drugs: Tramadol (an opioid with serotonergic and noradrenergic activity — a key suspect, especially in CKD where metabolites accumulate; it causes sedation and cognitive impairment, and in combination with mirtazapine raises the risk of serotonin syndrome). Mirtazapine (sedating, anticholinergic, serotonergic). Furosemide (causes dehydration and electrolyte disturbance). Tamsulosin (alpha-blocker — contributes to hypotension). The combination of bisoprolol, furosemide, spironolactone, and tamsulosin is likely contributing to his hypotension (96/58), which itself causes cerebral hypoperfusion and delirium.
• E — Electrolytes and dehydration: Sodium (hyponatraemia from the diuretics and possible SIADH), potassium, renal function (his CKD may have worsened), glucose, calcium, albumin. Dehydration from over-diuresis is a strong suspect given his hypotension.
• L — Lack of drugs: Unlikely — no history of alcohol or benzodiazepine use — but I will ask.
• I — Infection: The single most common precipitant in older adults. I will dipstick and culture the urine (UTI, especially given his BPH and possible retention), check full blood count and CRP, blood cultures, chest X-ray (pneumonia, heart failure), and examine for cellulitis and intra-abdominal sepsis. Note that older adults may not mount a fever — a normal temperature does not exclude infection.
• R — Reduced sensory input: He may not have his glasses or hearing aids in the emergency department — I would ensure these are provided.
• I — Intracranial/CNS: A focused neurological examination for focal signs (he may have had a stroke — his ischaemic heart disease and AF risk are relevant; right hemisphere and parietal strokes present with confusion). If there is any focal sign, or if the delirium does not begin to resolve with treatment of the precipitants, I would arrange a CT brain to exclude a subdural (he is on aspirin and may have fallen), an infarct, or a haemorrhage.
• U — Urinary and faecal: A bladder scan for urinary retention (his BPH, tamsulosin, immobility, and opioids all predispose to retention), and a rectal examination for faecal impaction.
• M — Myocardial and metabolic: ECG and troponin (silent myocardial infarction — he is elderly with ischaemic heart disease and may not present with typical chest pain). His oxygen saturation of 94 percent warrants a blood gas to exclude hypercapnia (especially with opioid sedation) and hypoxia. His hypotension (96/58) suggests possible cardiogenic shock, dehydration, sepsis, or medication effect — I would assess volume status clinically, and consider that the combination of bisoprolol, furosemide, spironolactone, and tamsulosin may be over-treating his blood pressure. Thyroid function, and consider B12 and folate if there is a suggestive picture. [1]

Initial management priorities (3 marks): [1]

1. Address the airway, breathing and circulation first — his oxygen saturation of 94 percent and his hypotension are the immediate priorities. I would give oxygen to target 94 to 98 percent (or 88 to 92 percent if he has chronic CO2 retention), obtain intravenous access, assess volume status, and treat hypotension with intravenous fluids (cautiously, given his heart failure) or inotropes if cardiogenic. I would review and reduce his antihypertensives (stop or reduce the furosemide and consider holding the spironolactone and tamsulosin while hypotensive).
2. Stop the precipitating drugs — stop the tramadol (and switch to paracetamol for pain, or a renal-adjusted dose of a different opioid if pain is severe), review the mirtazapine (continue for now as abrupt cessation risks withdrawal, but flag it for review), and simplify the medication regimen.
3. Treat any identified infection with appropriate antibiotics at renal-adjusted doses, relieve urinary retention with a catheter if present, treat any electrolyte disturbance, and provide supportive non-pharmacological delirium care (reorientation, hydration, sensory aids, mobility, family or familiar staff presence).
4. Avoid benzodiazepines and antipsychotics unless absolutely necessary — hypoactive delirium does not require sedation (the patient is already drowsy); the priority is the cause search and supportive care. [1]

I would arrange early geriatric or general medicine input, and plan a comprehensive geriatric assessment once the acute delirium has resolved, to address his polypharmacy, his depression, his functional status, and his prognosis. [1]