Isolated new onset 'atypical' optic neuritis in the NMO clinic: serum antibodies, prognoses and diagnoses at follow-up.

Severe, recurrent or bilateral optic neuritis (ON) often falls within the neuromyelitis optica spectrum disorders (NMOSD), but the diagnosis can be particularly challenging and has important treatment implications. We report the features, course and outcomes of patients presenting with atypical ON when isolated at onset. We retrospectively analyzed 69 sequential patients referred to a single UK NMO center with isolated ON at onset. Aquaporin-4 antibody (AQP4-Ab) assessment was performed in all patients and IgG1 myelin-oligodenrocyte glycoprotein (MOG-Ab) in AQP4-Ab(neg) patients. 37 AQP4-Ab positive (AQP4-Ab(pos)) and 32 AQP4-Ab negative (AQP4-Ab(neg)) patients (8 with MOG-Ab) were identified. The AQP4-Ab(neg) group included heterogeneous diagnoses: multiple sclerosis (MS), NMO, relapsing isolated ON (RION), monophasic isolated ON and relapsing acute disseminated encephalomyelitis (ADEM)-like syndromes. Compared to AQP4-Ab(neg) patients, AQP4-Ab(pos) patients had a worse residual visual outcome from first attack (median VFSS 4 vs. 0, p = 0.010) and at last assessment (median VFSS 5 versus 2, p = 0.005). However, AQP4-Ab(neg) patients with RION also had poor visual outcome. Up to 35% of AQP4-Ab(neg) patients developed a LETM and two developed low positivity for AQP4-Ab over time. Eight AQP4-Ab(neg) patients (25%) were MOG-Ab positive, covering a range of phenotypes excluding MS; the first ON attack was often bilateral and most had relapsing disease with a poor final visual outcome [VFSS 4, range (0-6)]. In conlcusion, AQP4-Ab positivity is confirmed as a predictor of poor visual outcome but AQP4-Ab(neg) RION also had a poor visual outcome. Of those without AQP4-Ab, 25% had MOG-Ab and another 25% developed MS; thus, MOG-Ab is associated with AQP4-Ab(neg) non-MS ON.

The prevalence of neuromyelitis optica in South East Wales.

BACKGROUND AND PURPOSE: Neuromyeltis optica (NMO) is a neuroinflammatory disorder considered rare in Caucasian populations. However, accurate population-based epidemiological data for NMO and NMO spectrum disorder (NMO-SD) from Western populations employing validated diagnostic criteria remain limited. We sought therefore to estimate the prevalence and clinical features of NMO in a north European Caucasian population in South East Wales. METHODS: Patients were identified by a comprehensive, multistage ascertainment strategy employing a regional neuroinflammatory disease register, hospital diagnostic databases personal physician referrals and regional requests for anti-aquaporin-4 antibodies (anti-AQP4). RESULTS: Fourteen Caucasian patients (11 patients with NMO and three with NMO-SD) were identified in a population of 712,572 (19.6/million; 95% CIs: 12.2-29.7). There was an excess of females (female:male 12:2), 11/14 were anti-AQP4 positive and 5/14 had disease onset under the age of 20 years. CONCLUSION: This study suggests that NMO and related spectrum disorders are at least as frequent in Northern European populations as in non-Caucasian populations and that the demographic profile of prevalent patients differs from clinic-based cohorts.