West Nile Virus Meningoencephalitis in an Infant With Seizures and Abnormal Neuroimaging.

In August 2012, a 41-day-old, full-term female presented to Texas Children’s Hospital after a 1-day history of fever, irritability, and a disinterest in breastfeeding. On physical examination, she had a temperature of 100.6°F, a heart rate of 170/minute, and a respiratory rate of 40/minute, with normal pulse oximetry. She weighed 4.7 kg (71 percentile). She was irritable but consolable. Her anterior fontanel was soft and flat. She had no conjunctival injection or discharge, no rhinorrhea, and her oropharynx appeared normal. She had clear breath sounds, and her heart examination was normal except for a rapid rate. She had normal pulses and capillary refill time. Her abdominal and musculoskeletal examinations were normal. She had no lymphadenopathy or rash. She had no evidence of nuchal rigidity and had a normal cry and suck without facial palsy. She had normal tone and moved all extremities equally. Her deep tendon reflexes were equal in all extremities. She had a normal grasp and palmar reflex and a normal Moro reflex. Her peripheral white blood cell count (WBC) was 13 470/mm with 13.4% neutrophils and 43.4% lymphocytes; hemoglobin was 11.5 g/dL and platelet count of 381 000/mm. Her urinalysis was normal. Her cerebral spinal fluid (CSF) had a WBC of 85 cells/mm (monocytes [64%], lymphocytes [19%], and neutrophils [14%]), a red blood cell (RBC) count of 6 cells/mm; protein of 79 mg/dL and glucose of 39 mg/dL. Her CSF gram stain was negative. Blood and CSF were sent for enterovirus polymerase chain reaction (PCR) testing. Ampicillin and cefotaxime were administered. On her second hospital day, she developed rhythmic right eye deviation and right face twitching for 20 seconds. She had 8 similar episodes, the longest lasted 12 minutes, which spontaneously resolved followed by a postictal period. The pediatric Neurology team recommended starting levetiracetam antiepileptic therapy. Due to concerns for herpes simplex virus (HSV) encephalitis, a lumbar puncture was attempted for HSV PCR testing and was unsuccessful. On day of life 44, the patient’s blood was sent for an HSV PCR and a serum arbovirus panel (which included immunoglobulin [Ig] M and IgG antibody testing for West Nile, Western Equine Encephalitis, Eastern Equine Encephalitis, California Encephalitis Group, and St. Louis Encephalitis). She was started on intravenous acyclovir (20 mg/kg per dose every 8 hours). Magnetic resonance imaging of the brain revealed a hypodense focus in the left thalamus (4 mm in diameter), suggestive of a lacunar infarct and leptomeningeal enhancement at the left posterior cranial vertex, most prominent along the central sulcus (Figure 1). On her fourth hospital day, the patient had no further seizures and blood and CSF cultures were negative for bacterial growth. Her antibiotic treatment was discontinued. On day of life 47, additional CSF was obtained for HSV PCR testing and was improved with a WBC count of 35 cells/mm (lymphocytes [63%], and monocytes [36%], neutrophils [1%]), a RBC count of 475 cells/mm, protein of 74 mg/dL, and glucose of 30 mg/dL. Her mother felt that she was eating and acting better. On further discussions with the patient’s mother she stated that she herself had experienced 3 days of “tiredness,” mild headache, body rash, and nonbloody diarrhea the week before her infant became sick but denied feeling ill or having similar symptoms during her pregnancy. The infant had not been in contact with any additional persons who were ill, had no known mosquito exposure, and had no recent travel outside of their hometown (a suburb of Houston, Texas). On her day of discharge to home, the patient’s HSV PCR testing in the blood and CSF were both negative and Case Report