An adult case of hand, foot, and mouth disease caused by enterovirus 71 accompanied by opsoclonus myoclonica.

We reported a 23-year-old female who was treated for rash due to hand, foot, and mouth disease (HFMD). On day 4 of hospitalization, the patient showed opsoclonus (jerky eye movements in all directions), myoclonus of the neck, trunk, and extremities, and cerebellar ataxia. Based on the changes in serum viral antibody titer, the patient was diagnosed as enterovirus 71 infection. No obvious abnormal findings were noted in head MRI. Immunoglobulin 5 g/day was administered for 3 days in the early stages of infection, and administration of methylprednisolone 500 mg/day for 3 days was repeated twice. Afterwards, oral corticosteroids were given, resulting in neurological improvements a month. Including our case, there are only 2 cases within opsoclonus myoclonica associated with enterovirus 71 infection. Our case suggests, based on the course of treatment, possible involvement of direct viral action or autoimmune response in opsoclonus myoclonica.