A 32-year-old woman, who is on the combined oral contraceptive | Neurology collections 2020

A 32-year-old woman, who is on the combined oral contraceptive pill and who is a smoker, presents with a
history of pain and swelling in her right calf, starting two days earlier.
On the morning of admission, she developed sudden onset of weakness on her right side, with pleuritic chest
pain.
On examination she has a dense hemiplegia, with weakness of her right hand and upper motor neuron signs.
There is evidence of a deep vein thrombosis of her left calf.
What is the most likely diagnosis?