22nd May 2025

A 72-year-old lady is brought to the emergency department with reduced GCS (E4V4M3).

A 72-year-old lady is brought to the emergency department with reduced GCS (E4V4M3). She is noted to have a temperature of 35.5C. An urgent CT head does not find any acute abnormality and the initial venous blood gas shows a normal pH, pCO2 and bicarbonate. Her neighbour reports of general decline in her memory and, more recently, of low mood and lethargy for which the GP recently started her on sertraline. She has a past medical history of hypothyroidism, tissue aortic valve, gastro-oesophageal reflux disease and raised cholesterol. Her regular medications include levothyroxine, omeprazole and simvastatin. The ambulance crew finds unopened medication packs. What is the most likely cause of her symptoms?

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