20th July 2023

A 92-year-old man is admitted from his nursing home due to a 3-day history of increasingly challenging behaviour mixed with periods of drowsiness.

A 92-year-old man is admitted from his nursing home due to a 3-day history of increasingly challenging behaviour mixed with periods of drowsiness. He is normally confused, requires assistance for personal care and mobilises with a Zimmer frame and the assistance of one.

Past medical history: Alzheimer’s dementia, hypertension, and Chronic Obstructive Pulmonary Disease (COPD).

Medication: memantine hydrochloride 20mg once daily, amlodipine 10mg once daily, ramipril 7.5mg once daily, tiotropium 18 micrograms once daily, beclomethasone with formoterol 200/6 micrograms two puffs twice daily.

On examination, he is confused and appears distressed. He has vesicular breath sounds. Heart sounds I + II, with no added sounds. His abdomen is soft, but he appears to have some lower abdominal discomfort and corresponding dullness to percussion over the same area.

Observations: RR 19, SpO2 91% on room air, HR 115bpm, BP 147/94, Temperature 36.7°C

Blood results:

• Haemoglobin 141 g/l (130-180 g/l)
• White cell count 4.2 x 10⁹/l (3.6-11.0 x 10⁹/l)
• CRP 4 mg/l (<5mg/l)
• Urea 7.7 mmol/l (2.5 – 7.8 mmol/l)
• Creatinine 103 μmol/l (59-104 μmol/l)

What is the most likely cause of this patient’s change in behaviour?

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