Opsoclonus-Myoclonus Syndrome with Prominent Tremor: A Unique Presentation of West Nile Virus
Emma Frost1, Arthur Gribachov2, Cristian Cirjan3, Alison Riggs1, Olga Thon4, Swarna Rajagopalan5, Jesse Thon2
1Cooper University Healthcare/CMSRU, 2Cooper University Hospital, 3Cooper University Hosptial, 4Cooper Neurological Institute, 5University of Pennsylvania
Objective:
Identify a unique presentation of West Nile Virus
Background:
Opsoclonus-myoclonus-ataxia syndrome (OMS) is characterized by multidirectional erratic eye movements, myoclonus, and truncal ataxia. This clinical presentation often raises suspicion for paraneoplastic or autoimmune neurological causes, given their known association with this syndrome. Recently, alternative etiologies have been reported, including neuroinvasive infections. We describe a unique case of WNV associated encephalitis that presented with OMS and prominent diffuse tremor.
Results:
Case Report:
A 69-year-old man with no significant medical history presented with a constellation of fever, nausea, vomiting, headache, tremor, gait dysfunction, and dizziness for one week. On examination, he had prominent opsoclonus, diffuse chin, upper and lower extremity high frequency, low amplitude tremor with superimposed extremity and palatal myoclonus, as well as truncal and appendicular ataxia. He then developed severe dysphagia, hypophonia, and dyspnea requiring monitoring in the intensive care unit. MRI brain and spine with contrast were normal. CSF analysis showed a lymphocytic pleocytosis (60->32 WBC, 78% lymphs), elevated protein (127 mg/dL), and normal glucose. He was found to have positive CSF WNV antibodies (IgM >5.0, IgG 1.83). Laboratory workup for other etiologies was negative. He was treated with plasmapheresis and IV steroids. His mentation improved and opsoclonus, myoclonus, and ataxia resolved. Following cessation of steroids, these symptoms returned then resolved following initiation of a PO steroid taper. His tremor greatly improved with primidone and he was discharged to acute rehab.
Conclusions:
WNV should be considered in patients who present with OMS, especially if there are associated infectious symptoms. A prominent tremor may also be present, and the condition may respond to immunologic treatment such as plasmapheresis and steroids.
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