Acute Confusion After Hip Repair: Delirium and the Reversible Causes
Mrs. K, 81, is post-op day 2 after surgical repair of a hip fracture. She lives alone and managed her own medications before admission; family reports 'some forgetfulness,' but she was oriented to person, place, and time at baseline. Overnight she became agitated, pulled at her IV and Foley, and did not recognize her daughter. She is now oriented to person only, fluctuating between calm and agitated. RR 22, SpO2 92% on room air, T 37.9 C, HR 104, BP 150/84. Medications: oxycodone 10 mg every 4 hours PRN (last dose 2 hours ago), diphenhydramine 25 mg at bedtime PRN, enoxaparin, cefazolin. Last bowel movement 3 days ago. Bladder scan shows 480 mL.
1. Is this delirium, dementia, or both? What evidence supports your conclusion, and what is the most likely underlying cause?
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Delirium until proven otherwise, possibly superimposed on mild baseline cognitive impairment.
The family's 'some forgetfulness' may be mild cognitive impairment or early dementia, which raises risk but does not explain an abrupt overnight change. Delirium is supported by acute onset over hours, a fluctuating course, inattention, disorientation, failure to recognize a family member, and pulling at lines. Dementia is insidious and stable across the day; depression can mimic cognitive change but does not fluctuate this way.
Likely contributors, in order of immediacy:
- Urinary retention - 480 mL on bladder scan; a classic reversible cause and a common post-op problem
- Hypoxemia - SpO2 92%, RR 22
- Diphenhydramine - strongly anticholinergic, on the Beers list of medications to avoid in older adults, and it worsens both delirium and retention
- Oxycodone - 10 mg every 4 hours PRN; assess sedation and pain, since undertreated pain is itself a delirium driver
- Constipation - no bowel movement in 3 days
- Possible infection - T 37.9, HR 104, post-op; consider urine, wound, chest
- Environment and tethers - Foley, IV, disrupted sleep, missing glasses or hearing aids, unfamiliar room, fall-risk precautions
2. What are your priority interventions in the next hour, and which medications will you question?
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Next hour, in this order:
- Relieve the retention - bladder scan, then straight catheterization or intermittent catheter per order; recheck post-void residual. Remove the Foley if it is no longer indicated (CAUTI risk and a physical tether).
- Oxygen to keep SpO2 at 94% or higher; recheck respiratory rate and saturation.
- Request discontinuation of diphenhydramine - anticholinergic, sedating, and a direct contributor to both delirium and retention.
- Reassess the opioid - reduce dose or frequency and use multimodal analgesia; do not withhold all analgesia, because pain drives delirium too.
- Nonpharmacologic first: reorientation, family at the bedside, glasses and hearing aids, lights on during the day and off at night, quiet room, mobilize when safe with fall precautions, bowel regimen, hydration.
- Avoid restraints; use the least restrictive measures and a sitter if needed.
- Do not use antipsychotics or benzodiazepines for routine delirium - they mask symptoms, prolong the episode, and increase falls.
Document the mental status exam with a validated tool at each shift.
3. How will you evaluate whether the plan is working, and what would prompt escalation?
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Evaluating: use the same tool that detected the problem (CAM or an equivalent delirium screen) at each shift, and track the reversible causes:
- Less fluctuation and improved attention; recognizes family members
- Post-void residual under 200 mL, or voiding spontaneously
- SpO2 at 94% or higher; normal respiratory rate
- Pain controlled without heavy sedation
- Bowel movement, tolerating fluids
- Safe mobility, no falls
Escalate and request a workup if:
- Level of consciousness declines, or the patient cannot protect the airway
- Worsening hypoxia, fever above 38.5 C, hypotension, or new tachycardia
- New focal neurologic deficit (consider stroke, especially after hip fracture with fat embolism risk)
- Agitation that endangers the patient or staff despite nonpharmacologic measures
- No improvement after correcting retention, oxygenation, medications, and constipation - then pursue urinalysis and culture, chest film, electrolytes, glucose, and a full medication review
Delirium is a medical emergency in older adults: it predicts falls, prolonged stay, and mortality, so the response is to find and fix the cause, not to sedate the symptom.