Bilateral optic neuropathy and unilateral tonic pupil associated with acute human herpesvirus 6 infection: a case report.

Background: Human herpesvirus 6 (HHV-6), a widespread virus and causative agent of exanthema subitum in children, has been associated with a number of neurologic disorders including cranial nerve palsies, seizures, encephalitis, meningitis, and multiple sclerosis.
Patient: A 31-year-old man presented with bilateral optic neuropathy, disc edema, and unilateral tonic pupil, which were found to be associated with acute HHV-6 infection. The patient had been suffering from juvenile diabetes for 5 years. One week after onset of intravenous antiviral therapy with foscarnet, disc edema subsided, and tonic pupil reaction was no longer detectable.
Conclusions: HHV-6 infection may play a role as a causative agent in patients with optic neuropathy and tonic pupil.