Bickerstaff brainstem encephalitis. A grave non-demyelinating disease with benign prognosis

We describe 6 patients with ophthalmoplegia, ataxia and normal or exaggerated deep tendon reflexes. All had been preceded by a febrile illness and had a full recovery without sequelae. The brainstem auditory evoked potentials showed a localised lesion in the upper brainstem while the pattern shift visual evoked potentials were normal and did not show any additional silent lesions. CSF IgG oligoclonal bands were not detected in any of the patients. MRI in 2 patients showed a confluent high intensity lesion in the upper mesencephalon and thalamus involving white and gray matter. Follow-up ranged from 6 to 24 months and showed no relapse.