A 33-year-old man developed diffuse subarachnoid haemorrhage following attempted radiofrequency ablation for trigeminal neuralgia. Over the next 2 weeks, he progressively developed multiple bilateral cranial nerve palsies, bilateral cerebellar signs, hypotonia of all four limbs and diminished vision in both eyes. A visual-evoked potential study revealed anterior visual pathway defect. A possibility of demyelination was considered and he was treated with corticosteroids. His neurological deficits improved gradually over the next 4 months. He later underwent microvascular decompression uneventfully with good pain relief. This complication has not been reported earlier and needs to be kept in mind while performing radiofrequency ablation.