[A case of neuromyelitis optica spectrum disorder in which headache preceded visual field disturbances by 2 months].

A quinquagenarian woman visited our hospital due to experiencing headache around the right upper eyelid for the previous 2 months. T2-weighted MRI of the head showed multiple high-signal-intensity lesions in the corpus callosum and bilateral corona radiata. She was thought to have an autoimmune disease and was treated with steroid pulse therapy, but the light reflex of the right eye diminished and the patient developed inferior horizontal hemianopsia. T2-weighted orbital MRI showed an enlarged right optic nerve, a high-intensity signal in the superior half of the optic nerve, and an enhancing effect. She also tested positive for anti-aquaporin 4 antibodies, so she was diagnosed with neuromyelitis optica spectrum disorder (NMOSD). This case shows that headache can be an initial symptom of NMOSD and that clinicians should consider NMOSD when attempting to diagnose patients presenting with headaches.