Posterior reversible encephalopathy syndrome in a patient with Bickerstaff's brainstem encephalitis

Background Bickerstaff's brainstem encephalitis ( BBE ) is characterized by acute ophthalmoplegia, ataxia and impaired consciousness. Serum anti‐ GQ 1b antibody in the acute phase has been detected in many BBE cases. Posterior reversible encephalopathy syndrome ( PRES ) is characterized by acute neurological symptoms with vasogenic edema in the bilateral parieto‐occipital regions. It has been pointed out that the activation of inflammatory cytokines might be involved in the pathophysiology of PRES and BBE . Case presentation A 37‐year‐old woman had an upper respiratory infection a week before losing consciousness. On admission, she was in a coma and her blood pressure was 134/96 mmHg. Doll's eye phenomenon was negative. Bilateral tendon reflexes were normal, although Babinski signs were bilateral positive. Cerebrospinal fluid examination showed normal protein concentration and cell counts. Brain magnetic resonance imaging findings were normal. We administered intravenous methylprednisolone therapy (1000 mg/day), acyclovir (1500 mg/day) and fosphenytoin sodium hydrate (22.5 mg/kg/day). Brain magnetic resonance imaging on the third admission day showed an increased apparent diffusion coefficient map, and high intensities in diffusion‐weighted imaging in the bilateral occipital cortex and subcortex, which are consistent with PRES . Nerve conduction studies were normal. The patient was treated with intravenous immunoglobulin therapy (0.4 g/kg/day) from the fourth admission day. Her consciousness level rapidly improved, and we were able to detect obvious ophthalmoplegia and limb ataxia. Diffusion‐weighted imaging was improved on the 13th day of admission. Serum anti‐ GQ 1b immunoglobulin G antibody on admission was positive. We ultimately diagnosed her with BBE . Conclusions We reported a rare case of BBE complicated with PRES .