Symptomatic Narcolepsy as a Presenting Feature of Neuromyelitis Optica.

Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness. It can be either primary or symptomatic due to other neurologic disorders. Neuromyelitis optica (NMO) is an inflammatory demyelinating disorder in which symptomatic narcolepsy is being described as one of the core clinical features. Here, we report a patient with NMO who presented with narcolepsy. Signal changes on magnetic resonance imaging in hypothalamus and other periventricular regions of high aquaporin-4 expression should prompt considering NMO as diagnosis. Serum anti-aquaporin-4 IgG antibody testing should be done in such cases, and appropriate treatment should be initiated to prevent further neurological worsening and relapses.