A Case of Post Encephalitic Optic Neuritis: Clinical Spectrum, Differential Diagnosis and Management

PURPOSE: Most cases of optic neuritis are idiopathic or are associated with multiple sclerosis. We present a case in which a young female developed post-infectious left optic neuritis following herpes simplex encephalitis (HSE). CASE REPORT: A 24-year-old female presented with a severe headache, fever, and malaise of a one-week duration. Viral encephalitis was diagnosed and treated; intravenous acyclovir (750 mg every 8 h) was administered for 14 days. The patient improved clinically and was prescribed oral valacyclovir (1,000 mg, three times daily) for an additional 3 months as an outpatient. The patient presented again four weeks after the initial admission with left periocular pain and other typical manifestations of optic neuritis. We diagnosed post-infectious left optic neuritis following viral encephalitis. Corticosteroid therapy with 250 mg intravenous methylprednisolone every 6 hours was initiated and the patient showed rapid significant recovery. CONCLUSION: This case report highlights the patient's clinical course and includes a brief history of the systemic effects of HSE, as well as the pathophysiology, management, and differential diagnosis of post-encephalitic optic neuritis. We suggest that clinicians should routinely perform an ophthalmologic examination during the follow-up visits of such patients.