Agitation on Postoperative Day 3: Delirium, Not the Onset of Dementia
An 80-year-old man is on postoperative day 3 after open reduction and internal fixation of a hip fracture. He lived alone, drove, and managed his own finances before the fall. Overnight he became agitated, pulled out his IV, accused the nursing staff of poisoning him, and did not recognize his daughter. Between episodes he is drowsy and drifts off mid-sentence. Medications: scheduled oxycodone, diphenhydramine at bedtime for sleep, oxybutynin (long-standing for urinary urgency), prophylactic enoxaparin, and cefazolin. Vitals: HR 104, BP 148/82, SpO2 93% on room air, temperature 37.9 °C. He has not had a bowel movement in three days and has not voided in nine hours. His daughter asks whether this is "just his age" or the beginning of Alzheimer disease.
1. What is the diagnosis, and what features in this vignette distinguish it from dementia and from depression?
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Delirium - hyperactive and mixed, superimposed on a preoperative baseline that was intact.
Distinguishing features:
- Acute onset and fluctuating course over hours to days. Dementia is insidious and progressive over months to years; depression evolves over weeks and is characterized by sustained low mood and anhedonia, not by hallucinations and IV-pulling.
- Inattention is the cardinal feature - he drifts off mid-sentence. That is not explained by dementia alone at this stage.
- Disorientation and perceptual disturbance (misidentification, persecutory delusion) are common in delirium.
- Reversal of sleep-wake cycle and drowsiness alternating with agitation.
- Critically, he had high premorbid function - living alone, driving, handling finances - so there is no established dementia to explain this.
- He is also not depressed; the presentation is acute, fluctuating, and psychotic rather than a persistent mood syndrome.
Delirium is a medical emergency with mortality comparable to major acute illness, and it is a marker of an underlying cause until proven otherwise. It also independently predicts functional decline and long-term cognitive impairment. Say this out loud to the family so they understand why you are not simply sedating him.
2. What is your workup and first-line management, and which of his medications do you stop?
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First-line management is nonpharmacologic, plus a hunt for the cause - not a sedative.
Immediate causes to exclude in this patient:
- Urinary retention (nine hours without voiding) - bladder scan, then catheterize if retained. This alone can drive agitation.
- Constipation/fecal impaction (three days, opioid exposure).
- Pain - undertreated pain causes delirium as readily as opioids do; assess with a tool rather than assuming.
- Hypoxia - SpO2 93% and HR 104 in a postoperative patient raises atelectasis, PE, and pneumonia; check blood gas/chest imaging as indicated.
- Infection - temperature 37.9 °C, tachycardia: urinalysis and culture, chest imaging, wound check, CBC.
- Metabolic - electrolytes, glucose, renal function, calcium; also check for alcohol or benzodiazepine withdrawal.
- Drugs - look hard at the anticholinergic burden.
Stop the diphenhydramine and the oxybutynin - both are strongly anticholinergic and both are classic precipitants. Reassess the oxycodone dose and consider scheduled acetaminophen and regional analgesia to reduce opioid need.
Nonpharmacologic measures: orienting communication, glasses and hearing aids, daylight exposure, mobilization, family presence, sleep hygiene, and avoiding restraints and tethers.
3. The family asks whether he needs a sedative "to calm him down," and whether he should start donepezil. How do you respond?
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Antipsychotics are a last resort for dangerous agitation, at the lowest dose for the shortest time; benzodiazepines are avoided except in withdrawal; donepezil has no role in delirium.
Reasoning:
- Antipsychotics do not shorten delirium and carry real risk in older adults - QT prolongation, extrapyramidal effects, and increased mortality in dementia-related psychosis. They are justified when agitation threatens his safety or his ability to participate in essential care (debridement, mobilization), and only after nonpharmacologic measures and treatment of the cause have been tried.
- If needed: low-dose haloperidol or quetiapine, short-term, with an ECG if there is cardiac risk. Avoid benzodiazepines - they worsen and prolong delirium in older adults and are only appropriate for alcohol or benzodiazepine withdrawal.
- Donepezil: no. Cholinesterase inhibitors have no established benefit for delirium treatment or prevention, take weeks to have any effect, and cause bradycardia and GI side effects. It would not act in the relevant time frame.
- Counsel the family on prognosis: delirium usually resolves over days to weeks once the cause is treated, but it can take longer to fully clear, is associated with increased mortality and subsequent cognitive decline, and is not the first sign of Alzheimer disease in this presentation. Involve them in reorientation and ask them to bring in his glasses and hearing aids.
- Document a baseline cognitive assessment to repeat after recovery, so that if deficits persist you can evaluate properly.