A Case Report of Herpes Zoster-Associated Bickerstaff Brainstem Encephalitis

Background: Bickerstaff brainstem encephalitis (BBE) is a rare demyelinating disease of the central nervous system (CNS) that is caused by a direct viral infection or secondary autoimmune responses. BBE secondary to Herpes zoster has rarely been reported. Case Presentation: A 68-year-old man developed a painful vesicular rash and drooping eyelid on the left side of his face for 20 days. Physical examination revealed left-sided blepharoptosis and crusted erythema on the left front side of his face, left upper eyelid, and left nasal tip. Neurological examination showed impaired sensation over the left side of his face and cheek. His left pupil was dilated (4mm compared to 2mm on the right side), and the Pupillary light reflection (PLR) was absent, with an ocular movement disorder (limited adduction) and diplopia. Brain imaging did not reveal abnormalities. Cerebrospinal fluid (CSF) examination showed leukocytosis and increased protein levels. He was treated with intravenous acyclovir for 7 days, but developed disturbance of consciousness and right limb weakness. Neurological examination revealed right lower limb hypoesthesia. The Heel-Knee-Shin test was positive on the left side, and Babinski's sign was present on the right side. He was diagnosed with Bickerstaff brainstem encephalitis caused by herpes zoster. After 2 days of intravenous acyclovir combined with intravenous immune globulin (IVIG), the patient developed acute kidney injury (AKI). Then, his treatment was changed to systemic steroids. At the 3-month follow-up, his pupils were bilaterally equal and reactive to light, and there was a significant improvement in ocular motility and ptosis. At the 6-month follow-up, his diplopia had completely resolved. Conclusion: BBE associated with herpes zoster is very rare and can be overlooked. Dermatologists should be aware of the expanding spectrum of neurological complications caused by varicella zoster virus (VZV) infections to aid early diagnosis and treatment.