A 59-year-old woman presented with 6-week history of recurrent haematuria. Her medical history was unremarkable apart from a 22-pack-year smoking history and hypothyroidism. There was no history of alcohol or drug abuse. Physical examination was normal. An intravenous pyelogram showed a pedunculated tumour in the bladder mucosa, for which she underwent a transurethral resection under spinal anaesthesia. The preoperative clinical and laboratory assessments, including a chest x-ray, were normal, apart from haematuria. Her intraoperative electrocardiogram was normal, her oxygen saturation was >98%, and there were no respiratory symptoms. The biopsy revealed a low-grade papillary urothelial carcinoma.

The patient recovered uneventfully from the spinal anaesthetic. However, the next morning, approximately 12 h after the operation, she developed mild leg numbness and could not move her legs. An urgent neurology opinion was requested.

She was alert but apathetic. There was marked but painless weakness of both legs with absent deep tendon reflexes and equivocal plantar responses. Pain and temperature sensation were mildly reduced in both legs but vibration and joint position sense were normal. She could urinate and defecate normally.