A 65-year-old man recovering from CABG surgery develops sudden disorientation, visual hallucinations, and agitation on the 3rd post-operative night. He has a normal WBC and afebrile. Which is the MOST likely diagnosis and its predisposing factor?
- A Delirium tremens due to unrecognised alcohol dependence
- B ICU psychosis exclusively from haloperidol prescribed preventively
- C Acute onset Alzheimer's dementia triggered by surgical stress
- D Post-operative delirium; age, surgery duration, sleep disruption, and ICU environment are predisposing factors ✓
Explanation
Post-operative delirium (acute confusion) is extremely common after cardiac surgery in elderly patients. Predisposing factors include advanced age, pre-existing cognitive decline, pain, sleep deprivation, sensory overload, metabolic disturbances, anticholinergic medications, and immobility. Visual hallucinations, disorientation, and fluctuating consciousness arising acutely post-operatively are classic. Alzheimer's does not present acutely in this manner. While delirium tremens is possible, it typically appears within 48–72 hours of alcohol cessation with autonomic features; the question describes a typical post-operative delirium picture.
Reference: Kaplan & Sadock's Synopsis of Psychiatry, 11th ed.
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