Baylor University Medical Center Proceedings April 2014, Volume 27, Number 2 | Page 34

Opsoclonus myoclonus syndrome: an unusual presentation for West Nile virus encephalitis Aasim Afzal, MD, Sahar Ashraf, MD, and Sadat Shamim, MD A record number of West Nile virus (WNV) cases and fatalities seen in 2012 have brought to light the numerous manifestations of neuroinvasive disease. We report a case of opsoclonus myoclonus syndrome attributed to WNV and its clinical course after treatment with a combination of steroids and intravenous immunoglobulin. Our objective is to highlight opsoclonus myoclonus syndrome as a potential manifestation of WNV encephalitis. est Nile virus (WNV) is a mosquito-borne arbovirus belonging to the genus Flavivirus. It is more common in temperate and tropical regions of the world. Before the 1990s, it was not considered a big threat to the human population. However, WNV has now spread all over the world. The first case of WNV in the United States was reported in New York City in 1999; over the next 5 years, it spread across the nation (1). The main mode of transmission is mosquitoes, which are the prime vector, whereas birds are the prime reservoir host. WNV is also found in ticks, but they are not important vectors. WNV can also be spread by blood transfusion, organ transplantation, and breastfeeding (2). WNV infects various mammals, reptilian species, as well as amphibians (3). W CASE PRESENTATION A 43-year-old Caucasian woman presented to an outside facility in the fall of 2012 with a 10-day history of dizziness, worsening headaches, nausea, fever, and myalgias. Early in the course, she developed a raised nonerythem atous rash on her neck that spread in a craniocaudal fashion. One week after developing the rash, she started having involuntary multidirectional jerky saccadic eye movements with superimposed fluttering eyelid movements consistent with opsoclonus myoclonus syndrome (OMS). The patient’s past medical history was insignificant except for a cesarean section. She mentioned a family history of recurrent meningitis in her son, breast cancer in her mother, and prostate cancer in her father. Her social history was significant only for exposure to WNV, as she was a rancher in a neighborhood where others had been diagnosed with WNV. Her medications included occasional nonsteroidal antiinflammatory drugs and oral contraceptives. 108 At the time of admission, she appeared very uncomfortable and kept her eyes closed with myoclonic jerking of the eyelids whenever she tried to open them. Her vital signs revealed only low-grade fever, which resolved spontaneously. She had difficulty keeping her eyes open, and her eyes initially had to be pried open to examine her severe OMS. She had good muscle strength but her gait was ataxic. Opening her eyes or any movement triggered severe nausea and episodes of emesis. She stayed in bed in a dark room with her eyes clenched shut with a constant look of distress. However, her cognition remained unaffected. A thorough evaluation was done for the possibility of malignancies, paraneoplastic syndromes, autoimmune processes, and infectious etiologies as the cause of OMS. Her cerebrospinal fluid (CSF) was xanthochromic with lymphocytic pleocytosis (Table 1). Among the imaging studies performed at the outside facility, magnetic resonance (MR) imaging with contrast and MR angiography of the brain were nonrevealing. Computed tomography with contrast of the chest, abdomen, and pelvis Table 1. Results of laboratory tests of the patient’s cerebrospinal fluid Test Result Color Xanthochromic 49K RBC Lymphocyte (per μL) 30 Neutrophil (per μL) 62 Glucose (mg/dL) 47 Protein (mg/dL) 110 Culture No organisms Fungal culture Negative Paraneoplastic panel Negative HSV/HHV6/Coxsackie A-B/GQ1b Ab/VGCC/WNV IgM Negative HSV indicates herpes simplex virus; HHV6, human herpesvirus 6; Ab, antibody; VGCC, voltage-gated calcium channel; WNV, West Nile virus. From the Division of Neurology, Department of Internal Medicine, Baylor University Medical Center at Dallas. Corresponding author: Sadat Shamim, MD, 3600 Gaston Avenue, Suite 1155, Dallas, TX 75246 (e-mail: [email protected]). Proc (Bayl Univ Med Cent) 2014;27(2):108–110