A 16-year-old girl with systemic lupus erythematosus (SLE) nephritis was started on pulse methylprednisolone and monthly cyclophosphamide infusion. She was already on antihypertensive for border line hypertension (130/80–140/90 mm Hg). On day 4 of treatment she suddenly started complaining of headache and subtle neurological symptoms including disorientation, blurred vision and motor apraxia. This was followed by a brief episode of generalised fit. Apart from being in post-ictal aura her gross neurological examination including fundoscopy was unremarkable. Her blood pressure around this episode was 150/80–160/90 mm Hg. Serum electrolytes and calcium were within normal range.

Urgent neuroimaging was arranged. Axial fluid-attenuated …