16th February 2025

You see an 80-year-old woman with metastatic lung cancer due to new confusion. The medical team have been increasing the analgesia

You see an 80-year-old woman with metastatic lung cancer due to new confusion. The medical team have been increasing the analgesia over the last few days due to severe back pain. She denies being in pain but is now not oriented to time or place and keeps trying to reach and pick things off the curtain.

You review her most recent bloods which show the following:

FBC 123 (115-165 g/L), CRP 7 (<5 mg/L)

Na 146 (133 – 145 mmol/L) , K 4.5 (3.5 – 5.3 mmol/L), Cr 200 (45-84 µmol/L)

Previous blood results from 4 days ago were as follows:

FBC 118 (115-165 g/L), CRP 20 (<5 mg/L)

Na 143 (133 – 145 mmol/L) , K 4.0 (3.5 – 5.3 mmol/L), Cr 90 (45-84 µmol/L)

What is the most likely cause of her symptoms?

Select the SINGLE most appropriate option from the list below. Select ONE option only.