Also known as Devic’s disease, neuromyelitis optica (NMO) is an uncommon disease syndrome of the central nervous system (CNS) that affects the optic nerves and spinal cord. Individuals with NMO develop optic neuritis, which causes pain in the eye and vision loss, and transverse myelitis, which causes weakness, numbness, and sometimes paralysis of the arms and legs, along with sensory disturbances and loss of bladder and bowel control. NMO leads to loss of myelin, which is a fatty substance that surrounds nerve fibers and helps nerve signals move from cell to cell. Put briefly, NMO is a central nervous system disorder, which results in primarily swelling and inflammation of the eye nerves (optic neuritis) and the spinal cord (myelitis).
The condition occurs when your body’s immune system reacts against its own cells in the central nervous system, mainly in the optic nerves and spinal cord, but sometimes in the brain. The cause often is unknown, although it may sometimes appear after an infection, or it may be associated with another autoimmune condition. Historically, NMO was diagnosed in patients who experienced a rapid onset of blindness in one or both eyes, followed within days or weeks by varying degrees of paralysis in the arms and legs. In most cases, however, the interval between optic neuritis and transverse myelitis is significantly longer, sometimes as long as several years.
After the initial attack, NMO follows an unpredictable course. Most individuals with the syndrome experience clusters of attacks months or years apart, followed by partial recovery during periods of remission. This relapsing form of NMO primarily affects women. The female to male ratio is greater than 4:1. Another form of NMO, in which an individual only has a single, severe attack extending over a month or two, is most likely a distinct disease that affects men and women with equal frequency. The onset of NMO varies from childhood to adulthood, with two peaks, one in childhood and the other in adults in their 40s.
The recent discovery of an antibody in the blood of individuals with NMO gives doctors a reliable biomarker to distinguish NMO from multiple sclerosis. The antibody, known as NMO-IgG, seems to be present in about 70 percent of those with NMO and is not found in people with MS or other similar conditions.
When doctors at BRAINS suspect that you may be a patient of NMO they will begin with a detailed clinical examination aimed at evaluating your movement, muscle strength, coordination, sensation, memory and thinking (cognitive) functions, vision and speech. An eye doctor (ophthalmologist) also may be involved in this exercise. To confirm the diagnosis they may recommend MRI scans, blood serum tests and even a lumbar puncture (see Technology and Procedures).When doctors at BRAINS suspect that you may be a patient of NMO they will begin with a detailed clinical examination aimed at evaluating your movement, muscle strength, coordination, sensation, memory and thinking (cognitive) functions, and vision and speech. An eye doctor (ophthalmologist) also may be involved in this exercise. To confirm the diagnosis they may recommend MRI scans, blood serum tests and even a lumbar puncture (see Technology and Procedures).
BRAINS doctors trained in brain and nervous system conditions (neurologists) and others have experience treating people with neuromyelitis optica (NMO) and other neurological conditions. Neuromyelitis optica resembles multiple sclerosis (MS) in several ways, but requires different types of treatment involving therapies to reverse recent symptoms and prevent future attacks. In the early stage of an NMO attack, your doctor may put you on a calibrated course of corticosteroid medication injected through a vein in your arm (intravenously). If this does not help, your doctor may recommend plasma exchange (plasmapheresis). In this procedure, some blood is removed from your body, and blood cells are mechanically separated from fluid (plasma). Doctors mix your blood cells with a replacement solution and return it into your body. Our doctors can also help manage other symptoms you may experience, such as pain or muscle problems. To prevent future attacks they may recommend you take a lower dose of corticosteroids for an extensive period of time.
Magnetic resonance imaging (MRI): An MRI uses powerful magnets and radio waves to create a detailed view of your brain, optic nerves and spinal cord. Your doctor may be able to detect lesions or damaged areas in your brain, optic nerves or spinal cord.
Blood serum tests: In blood serum tests, doctors will test for the antibody NMO-IgG, which helps doctors distinguish NMO from MS and other neurological conditions. Your doctor can find this antibody by examining your blood sample, and, in some cases, your spinal fluid. This test helps doctors make an early diagnosis of NMO.
Lumbar puncture (spinal tap): During this test, your doctor will insert a needle into your lower back to remove a small amount of spinal fluid. Doctors test the levels of immune cells, proteins and antibodies in the fluid. This test may help your doctor differentiate NMO from MS. In NMO, the spinal fluid may show markedly elevated white blood cells during NMO episodes, greater than normally seen in MS, although this doesn’t always happen.