Dancing eyes: a case of opsoclonus, tremor and truncal ataxia secondary to West Nile encephalitis

Abstract

Background: Opsoclonus can result from paraneoplastic, parainfectious, autoimmune, ischemic or toxic etiologies. Neuroinvasive complications develop in less than one percent of individuals infected with West Nile Virus. Methods: Case report. Results: A 63-year-old female presented with subacute disorientation, dizziness, oscillopsia, and unsteady gait, associated with fever. Examination demonstrated opsoclonus, bilateral upper extremity postural and action tremor and truncal ataxia. MRI of the brain was normal. CT of the body showed no evidence of neoplasia. Vasculitic and paraneoplastic panels were negative. An extensive infectious work-up was only positive for West Nile IgM antibodies. She was treated with clonazepam and received a five-day-course of IVIG. Her symptoms improved after treatment and she continued to demonstrate gradual recovery during the months following her discharge. Conclusions: There are only a few published case reports of WNV-associated opsoclonus, and our patient appears to be the oldest reported with this constellation of neurological symptoms. Even though treatment for WNV is mostly supportive, this case demonstrates the importance of a thorough work-up in patients of similar presentations to determine the etiology and to guide early immunomodulation in selected cases. Video available.