Medicines for Neuromyelitis optica

What it is

Neuromyelitis optica (NMO), also known as neuromyelitis optica spectrum disorder (NMOSD) or Devic disease, is a rare autoimmune condition of the central nervous system (the brain and spinal cord), which mainly affects the optic nerves (the nerves for vision) and the spinal cord. In NMO, the immune system mistakenly attacks these parts of the nervous system, causing inflammation and damage. In many people with NMO, a specific antibody (against a protein called aquaporin-4) is found, which helps confirm the diagnosis and distinguishes NMO from some other conditions. NMO shares some features with multiple sclerosis (MS) and was once thought to be a form of it, but it is now recognised as a distinct condition, with different features, treatment, and course — so it is important to distinguish them, as the treatments differ. NMO typically causes attacks (relapses) of inflammation affecting the optic nerves and/or the spinal cord: an attack affecting the optic nerve (optic neuritis) causes symptoms such as loss of vision, blurred vision, or pain in the eye, often in one or both eyes; and an attack affecting the spinal cord (myelitis) causes symptoms such as weakness or paralysis (often of the legs, and sometimes more), numbness, altered sensation, and problems with bladder and bowel function. These attacks can be severe, and, importantly, in NMO the attacks can cause significant damage and disability if not treated promptly, and the condition tends to relapse (attacks recur over time) — so both treating attacks quickly and preventing future relapses are crucial. NMO is diagnosed by specialists (neurologists), based on the symptoms, examination, scans (MRI), the antibody test, and other tests. Although NMO is a serious condition, it is treatable: attacks are treated promptly to reduce the damage, and — very importantly — long-term treatment is used to prevent relapses (as preventing attacks prevents the accumulation of disability); newer treatments have improved the ability to prevent relapses. The key messages are that NMO is a rare autoimmune condition mainly affecting the optic nerves and spinal cord, causing attacks of vision loss and weakness, that it is distinct from MS, and that prompt treatment of attacks and preventing relapses are key.

How it is treated

Neuromyelitis optica is managed by specialists, with prompt treatment of attacks to reduce damage and, crucially, long-term treatment to prevent relapses, along with supportive care; distinguishing it from MS is important, as the treatments differ. Diagnosis is made by neurologists, based on the pattern of attacks affecting the optic nerves and/or spinal cord, examination, MRI scans, the aquaporin-4 antibody test (positive in many people with NMO), and other tests; distinguishing NMO from multiple sclerosis and other conditions is important, as the treatments differ and some MS treatments are not suitable for NMO. Treatment has two key aspects. First, treating attacks (relapses) promptly is important, because attacks in NMO can cause significant damage and disability, and prompt treatment reduces the damage: acute attacks are treated urgently, usually with high-dose steroids (corticosteroids) to reduce the inflammation, and, for severe attacks or those not responding, other treatments such as plasma exchange (a treatment that removes harmful antibodies from the blood) may be used; so it is important to recognise and seek urgent treatment for an attack (such as new vision loss, or new weakness, numbness, or bladder problems). Second, and very importantly, long-term treatment to prevent relapses is a cornerstone of NMO care, because the condition tends to relapse and because preventing attacks prevents the accumulation of damage and disability: this involves ongoing treatment with medicines that suppress or modify the immune system to reduce the frequency of attacks — a range of such treatments is used, and, importantly, newer targeted treatments have been developed specifically for NMO and have improved the ability to prevent relapses; this is a developing and improving area. Because preventing relapses is so important, staying on the preventive treatment as advised, and attending specialist follow-up, are essential. Alongside these, supportive care and rehabilitation help manage any lasting effects of attacks — such as physiotherapy and occupational therapy for weakness or mobility, support for vision, management of bladder and other symptoms, and support for the person and family. Because NMO is serious and relapsing, it is managed by specialist neurology services, with ongoing monitoring and support. The reassuring messages are that NMO, although a rare and serious relapsing condition, is treatable — with prompt treatment of attacks to reduce damage, and, crucially, long-term treatment to prevent relapses (with newer treatments improving this) — that it is distinct from MS (so accurate diagnosis matters for the right treatment), and that specialist care, supportive care, and staying on preventive treatment help; so specialist care, prompt treatment of attacks, and long-term relapse prevention are the keys to managing NMO.