[Successful plasma exchange treatment for a case with neuromyelitis optica]

We report a 13-year-old girl diagnosed with neuromyelitis optica (NMO). We also report that plasma exchange could be performed early in her clinical course as well as her good response to this treatment. At the onset, transient numbness of both upper extremities appeared. Approximately one month thereafter, photesthesia of the left eye disappeared and she visited our hospital. Optic neuritis and myelitis were diagnosed based on neuroimaging of the brain and spinal MRI scans. Intravenous high-dose methylprednisolone was administered. Subsequently, although left vision improved to 0.4, numbness of the hands and feet appeared during methylprednisolone therapy. Since anti-AQP-4 antibody seropositivity was confirmed after methylprednisolone therapy, she met the NMO diagnostic criteria. Therefore, plasma exchange was performed followed by high dose methylprednisolone therapy, which improved left vision to 0.8 and the sensory disturbance of the hands and feet disappeared. A 0.5 mg/kg/day dose of prednisolone was then administered prophylactically, followed by plasma exchange, and there has been no relapse to date. In general, the rate of NMO recurrence is high and the neurological prognosis is poor. Therefore, it is important to measure serum anti-AQP4 antibody during the first attack, if NMO is suspected, because this value is useful for the diagnosis of NMO. Appropriate treatments including plasma exchange and prophylactic therapy should be started after confirming the diagnosis.