Postoperative Confusion in an 82-Year-Old After Hip Fracture Surgery
An 82-year-old woman is admitted with a displaced femoral neck fracture after a fall at home. She lives alone, manages her own affairs, and her daughter says she is 'sharp as a pin' and has never been confused. She undergoes hemiarthroplasty under spinal anaesthesia. On the second postoperative day she becomes agitated, disoriented to place and time, and repeatedly tries to climb out of bed. Observations: temperature 37.9 C, pulse 104, blood pressure 132/74, respiratory rate 22, oxygen saturation 93% on air, urine output low with dark urine. Medications include regular oxycodone, hyoscine butylbromide for bladder spasms, and prophylactic low-molecular-weight heparin. A urinary catheter was removed 12 hours ago. The night nurse documents 'confusion, likely due to dementia' and requests sedation.
1. Explain why labelling this as dementia is unsafe, and set out the differential diagnosis you would work through.
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Delirium and dementia are frequently confused, and the distinction matters because delirium is an acute medical emergency with an identifiable cause, whereas dementia is a gradual, progressive cognitive decline. The features here are those of hyperactive delirium: acute onset over hours to days, fluctuating attention and orientation, agitation, and disturbed sleep-wake pattern, in a patient whose daughter describes a previously intact baseline. There is no documented pre-existing cognitive impairment, and the trigger is obvious - major surgery, anaesthesia, immobility and a new environment.
The differential is broad and should be worked through systematically:
- Sepsis - temperature 37.9 C, tachycardia 104 and tachypnoea 22 are abnormal in an older adult, in whom infection often presents without fever. Consider urinary tract infection after catheter removal, pneumonia, wound infection and, in a prosthetic joint, deep infection.
- Hypoxia and respiratory failure - saturation 93% on air suggests atelectasis, aspiration or pulmonary embolism; postoperative patients are at high risk.
- Hypovolaemia and acute kidney injury - low output with dark urine suggests dehydration and possible rhabdomyolysis or contrast-related injury.
- Pain and inadequate analgesia - undertreated pain is a common, reversible delirium driver; so is opioid excess, and both must be considered.
- Drug effects - oxycodone (especially with renal impairment causing metabolite accumulation) and hyoscine butylbromide (anticholinergic) are both plausible contributors.
- Retention of urine after catheter removal, and constipation or faecal impaction.
- Metabolic causes - hypo- or hyperglycaemia, hyponatraemia, hypercalcaemia, uraemia, thyroid dysfunction.
- Neurological events - stroke, seizure, subdural haematoma after a fall; and alcohol or benzodiazepine withdrawal if relevant.
- Sensory factors - unfamiliar ward, poor lighting, missing glasses or hearing aids, sleep deprivation.
The judgement call is that 'likely dementia' closes the investigation prematurely and sedation would mask a treatable cause.
2. State your immediate management, including what you would say about the request for sedation.
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Immediate assessment: ABCDE approach with full observations, capillary glucose, venous blood gas, full blood count, urea and electrolytes, calcium, liver function, thyroid function, blood cultures, urine dipstick and culture, chest radiograph, and ECG. Review the medication chart and the operative and anaesthetic notes. Examine for wound infection, calf swelling, abdominal distension and bladder distension, and perform a focused neurological examination. Check for retained urine with a bladder scan.
Treat causes as they are found: oxygen to maintain saturations, cautious intravenous fluid resuscitation guided by assessment of volume status, analgesia reviewed and rationalised (avoiding renally cleared opioid metabolites where possible), stop the anticholinergic, treat constipation, and re-catheterise if retention is confirmed. Remove unnecessary tethers: drip stands, catheter bags, and monitoring leads where safe.
Non-pharmacological delirium care: a well-lit room, visible clock and calendar, familiar glasses and hearing aids, family presence, orientation and reorientation, mobilisation with physiotherapy, sleep hygiene with undisturbed nights, and a clear bowel and bladder plan. These are first-line and reduce both duration and complications.
On sedation: I would decline routine sedation as a first response. Sedation treats the distress of staff rather than the cause, increases falls, aspiration and immobility, and prolongs delirium. It is justified only for severe agitation that endangers the patient or others, or for distressing hallucinations, and then it should be a short course of the lowest effective dose of an antipsychotic, with caution about QT prolongation and Parkinsonism, avoiding benzodiazepines except in withdrawal states. I would explain to the nursing team that the priority is finding and treating the cause, and I would document a delirium care plan and escalate to the orthogeriatric team.
Communication: inform the daughter of the change, explain that this is likely delirium and not necessarily dementia, and involve her in orientation and reassurance.