Case report: narcolepsy type 2 due to the optic nerve infection of Herpes zoster virus

Abstract Rationale: Despite the acknowledged importance of environmental risk factors in the etiology of narcolepsy, there is little research on this topic. The optic nerve infection of Herpes zoster virus as a trigger for narcolepsy has not been investigated.Patient concerns: A 63-year-old male carpenter complained of excessive daytime sleepiness (EDS) over the past 3 years.Interventions: Treated with duloxetine hydrochloride enteric dissolution capsule (Cymbalta) 120mg after breakfast and clonazepam tablets 0.5mg before sleep.Outcomes: General examination showed no abnormalities of his heart, lungs, or abdomen. Neurological examination showed no positive sign. The blood routine and biochemical examination were normal. Denied having been vaccinated against the flu or having been infected with the flu virus. He scored 17 on the Pittsburg sleep quality index, 22 on the Epworth sleepiness scale, 40 on the self-rating anxiety scale, and 69 on the self-rating depression scale. The multiple sleep latency test data showed 2 periods of sleep-onset rapid eyes movement period across 4 successive tests; the average sleep latency was 7.9 minutes, and the rapid eyes movement latency was 1.2 minutes. Treated with duloxetine hydrochloride enteric dissolution capsule (Cymbalta) 120mg after breakfast and clonazepam tablets 0.5mg before sleep, the patient’s EDS symptoms disappeared immediately. He scored 6 on the Epworth sleepiness scale. During our follow-up three months later, he remained well with no complications.Diagnosis: We diagnosed the patient with narcolepsy type 2 according to the 3rd Edition of International Classification of Sleep Disorders (ICSD-3).Conclusion: The patient suffered from EDS and was diagnosed with narcolepsy type 2. The narcolepsy type 2 was linked to viral infection of the optic nerve. Optic nerve virus infection may affect the sleep-pondering pathway.