A 28-year-old female with ulcerative colitis on azathioprine and prednisolone was commenced on intravenous infliximab for the worsening of symptoms. Two weeks after the second cycle, she presented with headache, confusion and blurred vision followed by a generalised tonic-clonic seizure.
Cerebrospinal fluid analysis is unremarkable.
Slices from T2 weighted MRI scan of the brain are depicted below (Figure 1):
a) What is the most likely diagnosis?
b) List four risk factors for this condition.