Neuromyelitis optica and neuromyelitis optica spectrum disorders have been recently associated with the disease-specific autoantibody aquaporin-4, thought to be pathogenic. Identifying this antibody has allowed the clinical phenotype to be broadened. It is clear that some patients with similar clinical features do not have this antibody and may have a different condition with different outcomes and prognosis. Previous clinical neuromyelitis optica and neuromyelitis optica spectrum disorder studies have included such patients. We investigated clinical outcomes and prognostic characteristics of 106 aquaporin-4 antibody-seropositive patients from the UK and Japan. We looked at predictors of disability outcomes, namely visual disability (permanent bilateral visual loss with visual acuity of <6/36 in the best eye), motor disability (permanent inability to walk further than 100 m unaided), wheelchair dependence and mortality. Data were collected largely retrospectively through review of case records. After median disease duration of 75 months, 18% had developed permanent bilateral visual disability, 34% permanent motor disability, 23% had become wheelchair dependent and 9% had died. Age at disease onset appeared to be an important predictor of disability type. Young-onset patients in the UK, but not the Japanese cohort, commonly presenting with optic neuritis, had a high risk of visual disability while older patients in both cohorts had a high risk of motor disability, regardless of their onset symptom. Genetic factors also appeared important. The UK cohort seemed to have more severe disease than the Japanese cohort, with more severe onset attacks, a higher relapse frequency and greater disability at follow-up, despite earlier immunosuppression. Moreover, within the UK cohort, there were important differences between ethnic groups, with Afro-Caribbean patients having a younger age at disease onset, more brain and multifocal attacks and higher likelihood of visual disability than Caucasian patients. Thus, age at disease onset and genetic factors are both likely to be important in determining clinical outcomes in aquaporin-4 disease. This has important implications for interpreting clinical neuromyelitis optica and neuromyelitis optica spectrum disorder studies, since clinical features and outcomes appear not to be generic across populations and may need to be tailored to individual groups. These factors need to be explored further in future prospective neuromyelitis optica and neuromyelitis optica spectrum disorder studies.

Using an international data set of 441 patients with AQP4-IgG positive NMOSD, and a collective history of almost 2000 attacks, Palace et al. apply mathematical modelling to predict likelihood of relapse and disability at different time points. Such estimates will help clinicians when counselling patients and aid drug trial design.

Neuromyelitis optica (NMO) has been described as a disease clinically characterised by severe optic neuritis (ON) and transverse myelitis (TM). Other features of NMO include female preponderance, longitudinally extensive spinal cord lesions (>3 vertebral segments), and absence of oligoclonal IgG bands . In spite of these differences from multiple sclerosis (MS), the relationship between NMO and MS has long been controversial. However, since the discovery of NMO-IgG or aquaporin-4 (AQP4) antibody (AQP4-antibody), an NMO-specific autoantibody to AQP4, the dominant water channel in the central nervous system densely expressed on end-feet of astrocytes, unique clinical features, MRI and other laboratory findings in NMO have been clarified further. AQP4-antibody is now the most important laboratory finding for the diagnosis of NMO. Apart from NMO, some patients with recurrent ON or recurrent longitudinally extensive myelitis alone are also often positive for AQP4-antibody. Moreover, studies of AQP4-antibody-positive patients have revealed that brain lesions are not uncommon in NMO, and some patterns appear to be unique to NMO. Thus, the spectrum of NMO is wider than mere ON and TM. Pathological analyses of autopsied cases strongly suggest that unlike MS, astrocytic damage is the primary pathology in NMO, and experimental studies confirm the pathogenicity of AQP4-antibody. Importantly, therapeutic outcomes of some immunological treatments are different between NMO and MS, making early differential diagnosis of these two disorders crucial. We provide an overview of the epidemiology, clinical and neuroimaging features, immunopathology and therapy of NMO and NMO spectrum disorders.

This study confirms the high frequency of brainstem symptoms in NMO with a majority of vomiting and hiccups. The prevalence of these manifestations was higher in the non Caucasian population.

LONMO/LONMOSD is particularly severe, with a high rate of motor impairment and death.

Neuromyelitis optica (NMO) is an immune-mediated neurological disorder characterised by recurrent episodes of optic neuritis and longitudinally extensive transverse myelitis. A serum biomarker, aquaporin-4 IgG, the autoantibody against aquaporin-4 water channel, has been specifically associated with NMO and has assisted early recognition and prediction of relapses. Less commonly, a monophasic course, associated with antibodies to myelin oligodendrocyte glycoprotein has been reported. Specific diagnostic criteria have been defined; however, some cases that do not fulfil these criteria (but are nevertheless associated with aquaporin-4 IgG) are classified as NMO spectrum disorder and follow the same relapsing course. An ever-growing list of autoimmune disorders, both organ-specific and non-organ-specific, have been associated in up to 20-30% of patients with NMO. These disorders, which may become symptomatic before or after the development of NMO, are often diagnosed long after the diagnosis of NMO, as symptoms may be wrongly attributed to NMO, its residual effects or medication side effects. In addition, autoantibodies can be found in patients with NMO without coexisting disease (up to 40% in some series) and maybe suggestive of a heightened humoral immune response. We present a comprehensive review of the current literature on autoimmune disorders co-existing with NMO and identified 22 autoimmune conditions (myasthenia gravis, coeliac disease, ulcerative colitis, sclerosing cholangitis, systemic lupus erythematosus, rheumatoid arthritis, antiphospholipid antibody syndrome, Sjogren's syndrome, autoimmune hypothyroidism, immune thrombocytopenic purpura, pernicious anaemia, narcolepsy, pemphigus foliaceus, alopecia areata, psoriasis, scleroderma, dermatitis herpetiformis, polymyositis, chronic inflammatory demyelinating polyneuropathy, paraneoplastic disorders, insulin dependent diabetes mellitus and autoimmune encephalitis).

Though pain in neuromyelitis optica (NMO) has been described in two recent reports, the proportion with true neuropathic pain (NP), its features, impact on activities of daily living (ADL) and quality of life has not been well characterised. A cross-sectional study of 50 NMO patients with transverse myelitis was performed using Douleur Neuropathique 4, Brief Pain Inventory, Extended Disability Status Scale and Short Form 36. NP was identified in 62% of patients. Pain was constant in 68% affecting most ADL. Pain was associated with significant reduction of the SF36 Mental Composite Score. The high prevalence of NP and associated disability necessitates an in-depth enquiry in patients with NMO.

Neuromyelitis optica (NMO) is an uncommon, demyelinating disease that causes long-term disability in adults. Though much has recently been learned about its pathogenesis, there are still only a few studies regarding the epidemiology of NMO. The aim of the study was to describe the epidemiology of NMO among adults in the Merseyside county of the United kingdom. Multiple overlapping sources of data were used including hospital records of The Walton Centre for Neurology and Neurosurgery in Liverpool, regional district general hospital data, central Aquaporin-4 antibody testing laboratory data and the British Neurological Surveillance Unit- to identify adults with a first-ever-in-a-lifetime diagnosis of NMO. As of December 31, 2010, there were eight cases (five NMO; three NMO spectrum disorder), indicating a prevalence of 7.2/million (95 % CI 3.1-14.2). Four incident cases of NMO and three incident cases of NMO spectrum disorder were identified in this period, indicating a minimum combined average annual incidence rate of 0.8/million (95 % CI 0.3-1.6). NMO still remains an uncommon condition, but the prevalence is rising with early diagnosis.