23rd July 2023

A 56-year-old woman is brought into A&E by the police. She had been found slumped in a doorway

A 56-year-old woman is brought into A&E by the police. She had been found slumped in a doorway, and when they approached her, she seemed confused. Her observations are all normal.

On examination, she is drowsy but wakes to voice. Her speech is slurred but there is no facial droop. There is yellowing of the sclerae and her skin is jaundiced. Her abdomen is soft with no organomegaly.

Pertinent blood results are a macrocytic anaemia, a raised white cell count with a neutrophilia, and a significantly raised AST, moderately raised ALT and a raised bilirubin. Glucose is normal.

You find records of a previous admission which confirms the patient has known liver cirrhosis. You suspect she has hepatic encephalopathy.

Hepatic encephalopathy is caused by the accumulation of which substance?

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