A 33-year-old female patient presents with a four-week history of bifrontal headache, decreasing visual acuity, and walking difficulties. She has no significant medical history. On examination of cranial nerves, there is bilateral VIth nerve palsy, and fundoscopy reveals bilateral papilloedema. Visual acuity is reduced, and gait is ataxic. Routine blood count reveals an elevated platelet count of 867 ×109/L. Haemoglobin, haematocrit, white cell count, iron store, and inflammatory markers are all normal. MRI brain shows cerebral venous sinus thrombosis with a small cerebellar haemorrhage. What is the best next step in managing this patient?