French guidelines for the diagnosis and management of neuromyelitis optica spectrum disorder.

Abstract

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune disease of the central nervous system, characterized by severe attacks. Optic neuritis is the most common clinical manifestation, leading to a rapid and often severe loss of vision, which is sometimes bilateral, with frequent sequelae and a risk of very low visual acuity in the long-term. Magnetic resonance imaging (MRI) reveals extensive lesions of the optic nerve, mostly involving the posterior part of the nerve and sometimes extending to the optic chiasm. Myelitis manifests as longitudinally extensive and centrally located spinal cord lesions, which may lead to tetraplegia, sensory disturbances, neuropathic pain and sphincter dysfunction. Area postrema syndrome presents with nausea, vomiting, and severe hiccups, which are often resistant to conventional treatments and may require hospitalization. Diagnosis is confirmed by the detection of anti-aquaporine 4 (AQP4) antibodies in the serum. Attacks should be treated as an emergency, with intravenous (IV) corticosteroids and plasma exchange, without waiting for antibody confirmation. Maintenance therapy includes monoclonal antibodies targeting B lymphocytes, interleukin-6 receptor, complement C5 and non-selective immunosuppressive treatments, according to profile of tolerance. Conventional treatments such as azathioprine or mycophenolate are less commonly used as first-line therapies but remain possible depending on the clinical context. Follow-up is multidisciplinary, with neurological, and according to the symptoms ophthalmological, neuropsychological, urodynamic or sequellar disability consultations. Therapeutic patient education and support from patient organizations are essential for improving quality of life and treatment adherence. Pregnancy is considered high-risk, requiring regular neurological and obstetric monitoring, as the risk of attack increases in the postpartum period. Finally, the rapid and individualized management of attacks as well as the prevention of relapses is crucial to limit functional sequelae and disability.