28th May 2025

An 82-year-old woman on an orthopaedic ward becomes unwell 72 hours after a total hip replacement.

An 82-year-old woman on an orthopaedic ward becomes unwell 72 hours after a total hip replacement. She is not sleeping, agitated, hallucinating and is very sensitive to noises on the ward. She has a history of anxiety and depression for which she takes regular sertraline and diazepam long-term, which she has not received on the ward. Her temperature and observations are unremarkable, and her CRP is 116. Her urine dip is negative for leucocytes and nitrites.

What is the most likely diagnosis?