Man with weakness of legs

An Asian male, 30, working as a pilot, came into the clinic and complained of weakness in his legs since 2 days ago. He also complained of tiredness ocassionally. There was no history of back pain or trauma. The history was otherwise normal.

On examination, his heart rate was 110bpm. The skin was warm and he was sweating profusely. His muscle strength and tendon reflex were good. The physical examination was otherwise normal.

Investigation was done and the doctor noted tat his Serum T3, T4 level were high, showing that he had thyrotoxicosis.

1. What is the most likely cause of the weakness in the legs?

(Clue: Asian male, thyrotoxicosis)

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