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.