A 13-year-old male presented with a corticosteroid-sensitive, varicella zoster virus (VZV)-related rapid loss of vision and bilateral disc edema after a febrile illness, and the case is reported from the University of Pittsburgh School of Medicine, Pittsburgh, PA. Increasingly slow and prolonged corticosteroids taper was required to avoid relapse of visual function over a 1 year period. VZV seroconversion occurred late in the course of the disease. Neuroimaging was unrevealing. CSF was under increased pressure (260 mm H20), protein 60 mg/dL, glucose 48 mg/dL, WBC 108 mm3 (84% lymphocytes), absent oligoclonal bands, IgG index 0.65 (N<0.7), and polymerase chain reaction for other viruses was negative. Initial treatment with acetazolamide was unsuccessful. When prednisone was substituted, disc edema slowly improved and visual acuity became normal. Tapering of prednisone after 6 weeks was followed by recurrence of disc edema and visual loss, MRI showed T2-signal hyperintensities in the right insular and frontal cortex regions, and in the upper cervical cord. The serum and CSF VZV complement fixation assays were now positive. Treatment with intermittent steroids and oral acyclovir was followed by remission and relapse over an 18-month period. At 1 year, the dose of prednisone was 20 mg every other day, visual acuity was 20/20, color perception 80%, but optic discs were pale and pupil responses were defective. Otherwise, the neurologic exam was normal. 
COMMENT. VZV may cause neurologic disease without a rash (zoster sine herpete), and complications associated with viral reactivation include optic neuritis, aseptic neuritis, myelitis, and encephalitis. Immunological mechanisms are considered likely. Since seroconversion to VZV occurred within 2 months of onset in the above case, VZV was considered the most likely cause of the optic neuritis, and multiple sclerosis or ADEM was a less plausible explanation.
VZV is a human herpes virus that causes varicella as a primary infection after which the virus lies dormant in the trigeminal and dorsal root ganglia. With reactivation, the virus causes herpes zoster, sometimes followed by post-herpetic neuralgia. In a review of advances in neurological infectious diseases, Kennedy PGE  cites a case of zoster sine herpete in a woman with a 13 month history of right maxillary trigeminal nerve pain, without rash, with a mass in the trigeminal ganglion and chronic ganglionitis. 
Ocular manifestations of the congenital varicella syndrome were described in 3 children seen at Great Ormond Street Hospital, London, UK (reviewed in Progress in Pediatric Neurology I, PNB Publ, 1991 ;424-5) . Ocular abnormalities followed a maternal varicella infection in the second trimester of pregnancy, and included chorioretinitis, atrophy of optic discs, cataract, and Horner’s syndrome. Neurologic complications included bulbar palsy, hemiparesis, learning disorder, and psychomotor retardation.
Varicella with delayed hemiplegia is described in 4 children reported from Japan. (PPN I, PNB 1991;425) . Cerebral angiitis with occlusion of the middle cerebral artery was cited as the cause. Neurologic complications of varicella are due to viremia with encephalitis, post-exanthematous encephalitis or cerebral angiitis. Cerebellar ataxia is the most frequent neurologic complication of varicella and hemiplegia is unusual.