AKT-4262

AKT-4262

A 60-year-old man is brought to his General Practitioner (GP) by his son. The son complains that his father’s personality has changed completely over the past year. Even at his best, he is forgetful and ‘switched off’. At worst, he is drowsy and unresponsive. He is particularly concerned that his father has been claiming to ‘see things that aren’t really there’. Over the past few weeks, he has also been tripping a lot on the carpet and is no longer safe on the stairs going to his bedroom unaccompanied. The GP gave the patient a small dose of a neuroleptic which ‘made things a million times worse’.
On examination, he has an inexpressive face, with a mild resting tremor and some axial rigidity. There is no other focal neurology. On mini-mental state examination, he scores 20/30.
What is the most likely primary brain pathology?