Uncommon Aetiology of a Posterior Circulation Stroke.

In this case, a patient presented with sudden-onset diplopia and persistent dizziness. A CT of the head showed two areas of hypoattenuation, one within each cerebellar hemisphere. MRI of the head with diffusion-weighted imaging (DWI) was consistent with bilateral cerebellar infarcts, but there was no convincing evidence of vasculitis. A CT angiogram raised the possibility of vertebral artery dissection. However, an interventional neuroradiologist reviewed the imaging and thought a dissection and cerebral vasculitis were unlikely. Due to persistent inflammatory markers, a PET scan was performed. This confirmed large vessel vasculitis as the cause of her stroke. A weaning regimen of prednisolone and weekly methotrexate was started. Vasculitis is a rare cause of strokes and can lead to diagnostic uncertainty and a delay in treatment.