Anti-aquaporin-4 Antibody Positive Optic Neuritis Following Scrub Typhus in an Elderly Female.

INTRODUCTION: Aquaporin-4 antibody (AQP4-Ab) is specific for neuromyelitis optica spectrum disorder (NMOSD) and so is helpful to distinguish NMOSD from other autoimmune diseases. Several viral infections may play a role in the onset of NMOSD.

CASE REPORT: We describe a case of a previous healthy 82-year-old woman who presented with acute visual loss occurring 3 weeks after scrub typhus. Physical examination showed a relatively afferent pupillary defect in the right eye and ophthalmoscopy revealed edema of the right optic disc. Enhanced magnetic resonance imaging revealed enhancement of the right optic nerve. Serological testing showed AQP4-Ab. After methylprednisolone pulse therapy followed by oral tapering of prednisolone, visual dysfunction was improved. Subsequently she experienced no attacks for 5 years.

CONCLUSIONS: Optic neuritis (ON) associated with scrub typhus is extremely rare. Our case support that scrub typhus could trigger ON in a lifelong asymptomatic patient with AQP4-Ab and AQP4-Ab should be considered in a very old age patient with suspected postinfectious inflammatory ON.