19th June 2023

A 28-year-old male presented to A&E with a 7-day history of headache, confusion, vomiting and tremor of his hands

A 28-year-old male presented to A&E with a 7-day history of headache, confusion, vomiting and tremor of his hands. His friends reported he had been backpacking to rural villages of Thailand, where he boasted of having stayed at a local farmer’s house to learn their culture and lifestyle, helping them on their fields and looking after farm animals.

On assessment, he was confused. There was no neck stiffness or rashes. Rigidity of his upper limbs and resting tremor were noted.

Bloods showed leucocytosis and mild hyponatraemia. Thick & thin blood film was normal.

CT head was normal.

LP is awaited.

Of the options below, which is the most likely diagnosis?