Echovirus Type 4 as a Probable Cause of Meningitis Associated with Bilateral Optic Neuritis

Abstract

Abstract: : Purpose: To present a case of acute bilateral optic neuritis and identify the microbiological etiology. Methods: The patient is a 25-year-old male, who had stayed in the Ivory Coast from May to the end of July 2002. A few days after his return to Finland he developed signs and symptoms of aseptic meningitis, followed by a bilateral optic neuritis one week later. Cerebrospinal fluid (CSF), blood, feces, and urine were widely tested for possible microbiological etiology, including polymerase chain reaction (PCR) for picornaviruses. Results: PCR revealed enteroviral RNA in the CSF and feces, and the virus was identified by culture to be Echovirus type 4. A wide array of diagnostic screens for other possible causative agents was unremarkable. MRI-scan of the brain and IgG-index of CSF were both normal. Clinical ophthalmologic examination including perimetry and pattern-VEP confirmed optic neuritis. At the beginning of symptoms of meningitis, leukocyte count of the CSF was 116 x 10⁶/L, containing 80% polymorphonuclear (PMN) and 20% mononuclear (MN) leukocytes. One week after the onset of meningitis CSF leukocyte level had declined to 26 x 10⁶/L with 100% of MN cells. First signs of optic neuritis were detected at this time. Conclusions: Parainfectious bilateral optic neuritis presenting after acute meningitis is a rare condition. In this case, the CSF contained predominantly PMN leukocytes at the onset of meningitis, and turned into purely mononuclear pleocytosis at the beginning of optic neuritis. Viral culture of the feces revealed Echovirus type 4 as the probable causative infectious agent underlying the disease. The patient underwent high-dose intravenous steroid treatment combined with intravenous gammaglobulin. Two months after the onset of optic neuritis, the BCVA had improved from finger counting to 0.8 in both eyes, and visual fields with Goldmann perimetry were normal.

Keywords: neuro-ophthalmology: optic nerve • microbial pathogenesis: clinical studies • neuro-ophthalmology: diagnosis