A woman with headache, hemiplegia, and recent toothache

A woman in her 60s presented to the emergency department with a two week history of headache and progressive left sided weakness over the previous 72 hours. She also had a two week history of toothache and was due to have an extraction procedure for a probable dental infection. She was otherwise well with no relevant medical history. She was alert and oriented but had a dense left sided hemiplegia (0 out of 5 on the Medical Research Council scale). She was afebrile. Table 1 shows the results of relevant blood tests.

Computed tomography with contrast and magnetic resonance imaging (MRI) of the brain showed a ring-enhancing lesion in the right frontal area, with an irregular enhancing rim (fig 1). MRI with apparent diffusion coefficient map, calculated using diffusion weighted imaging, …