Neuromyelitis optica and neuromyelitis optica spectrum disorder: Natural history and long-term outcome, an Indian experience

Background: Neuromyelitis optica (NMO) has evolved from devic′s classical description to a broader disease spectrum, from monophasic illness to a polyphasic illness with multiple recurrences, disease confined to optic nerve and spinal cord to now brain stem, cerebrum and even endocrinopathy due to hypothalamic involvement. Objectives: To report, the epidemiological characteristics, clinical presentations, recurrence rate, treatment and response to therapy in 26 patients with NMO and NMO spectrum disorder among the Indian population. Methods: We performed observational, retrospective analysis of our prospectively maintained data base of patients with NMO, longitudinally extensive transverse myelitis during the period of January 2003-December 2012 who satisfied the national multiple sclerosis society (NMSS) task force criteria for diagnosis of NMO and NMO spectrum disorder. Results: There were 26 patients (female: male, 21:5), the mean age of onset of symptom was 27 years (range 9-58, standard deviation = 12). Twenty-one patients (80%) fulfilled NMSS criteria for NMO while rest 5 patients (20%) were considered as NMO spectrum disorder. Seven patients (27%) had a monophasic illness, 19 patients (73%) had a polyphasic illness with recurrences. The Median recurrence rate was 4/patient in the polyphasic group. 13 (50%) patient were tested for aquaporin 4 antibody, 8 (61%) were positive while 5 patients (39%) were negative. All patients received intravenous methyl prednisolone, 9 patients (35%) required further treatment for acute illness in view of unresponsiveness to steroids. Thirteen patients (50%) received disease-modifying agents for recurrences. Mean duration of follow-up was 5 years. All patients had a good outcome (modified Rankin scale, <3) except one who had poor visual recovery. Conclusion: Neuromyelitis optica/NMO spectrum disorder is demyelinating disorder with female predominance, polyphasic course, myelitis being most common event although brain stem involvement is not uncommon with NMO antibody positivity in 60% patients, confirms the literature data