Neuromyelitis Optica (NMO)

Overview

What is neuromyelitis optica (NMO)?

Neuromyelitis optica (NMO), also known as NMO spectrum disorder or Devic's disease, is an autoimmune disease that mainly affects the optic nerve and spinal cord. (The optic nerve is made up of many nerve fibers that send visual information from the eye to the brain.) In NMO, the immune system attacks myelin, the substance that insulates nerves, in the spinal cord and optic nerve. As a result, people can develop optic neuritis and myelitis. Optic neuritis is a condition that typically leads to vision loss in one or both eyes, although many patients regain some sight. Myelitis is inflammation of the spinal cord. In NMO, myelitis commonly occurs at the same time as optic neuritis but can also happen before or after.

NMO most often affects adults, though it can develop in children as young as 3. In adults, it's more common in women; in children, no gender difference is seen.

Over time, people with the disease may alternate between periods of good health (remission) and disabling flare-ups (relapses). The flare-ups can be months or even years apart. Timely treatment can help control the symptoms, but most people eventually develop permanent muscle weakness and vision impairment. The prognosis for children with NMO varies.

Our approach to neuromyelitis optica (NMO)

The only program of its kind on the West Coast, our Pediatric Neuro-Immunology and Multiple Sclerosis Program provides complete specialty care for children and adolescents with NMO and related disorders, including optic neuritis, multiple sclerosis (MS) and acute disseminated encephalomyelitis (ADEM). The National Multiple Sclerosis Society has designated us a center of excellence in comprehensive care for pediatric patients with NMO and similar disorders.

Our team of experts includes adult and pediatric neurologists, pediatric nurse practitioners, neuropsychologists, social workers, physical therapists and speech therapists. We are dedicated to improving the treatment, diagnosis and awareness of children and adolescents with NMO.

Additionally, we are part of an international network of six pediatric MS centers sponsored by the National Multiple Sclerosis Society. As a result, we have access to the latest information, research and treatments for NMO, MS and related conditions.

Symptoms of NMO

A telltale sign of neuromyelitis optica is sudden loss of vision in both eyes. Other symptoms may include:

• Balance difficulties
• Problems with bladder or bowel function
• Weakness in the arms, legs or both
• Numbness in the arms, legs or both
• Sudden, brief, and sometimes repetitive spasms in arms and legs

Diagnosis of NMO

Early diagnosis of neuromyelitis optica is critical for effective management of the condition and to help maintain the child's quality of life.

At your child's initial evaluation, the doctor will ask about symptoms, perform a thorough physical exam, and review your child's medical history. You'll also be asked for information about your immediate and extended families' medical histories, as 3% of NMO cases are hereditary. In addition, a pediatric neurologist will perform a neurological exam to assess your child's physical abilities, brain function, vision and speech.

In many ways, NMO closely resembles multiple sclerosis (MS) and in early stages is sometimes misdiagnosed as MS. However, there are key differences that a neurologist can recognize. Generally, NMO attacks tend to be more frequent and severe than those of MS. Also, NMO affects only the optic nerve and spinal cord, while MS also affects the brain.

Additional testing can often determine which condition – NMO or MS – is causing your child's symptoms. These tests may include the following:

Magnetic resonance imaging (MRI) to diagnose NMO

Your child will have an MRI scan of the brain and spine. This technique uses a magnetic field and radio waves to create detailed images that can reveal lesions or damaged areas. In most cases, the scans of children with NMO show no brain damage but do show severe spinal cord inflammation, while those of children with MS show brain lesions and less prominent inflammation of the spinal cord.

Other tests to diagnose NMO

• Blood test. Certain detectable markers in the blood can indicate NMO.
• Lumbar puncture. For this test, also known as a spinal tap, the doctor inserts a needle into the lower back and withdraws a sample of cerebrospinal fluid (CSF), the substance that bathes, cushions and protects the brain and spinal cord. A lab test analyzes the CSF's levels of certain antibodies (disease-fighting proteins), which are higher in children with MS than in those with NMO.
• Eye exam. An ophthalmologist examines your child's eyes to check for optic nerve damage.
• Evoked potentials test. This measures the electrical activity in areas of the brain and spinal cord in response to certain stimuli. By indicating how well nerve signals reach the brain, the test can allow doctors to detect nerve damage that isn't yet apparent during a physical exam.

Treatment of NMO

Our experts will design a neuromyelitis optica treatment plan, including long-term follow-up care, tailored to your child's needs. When helpful, we collaborate with other specialists at UCSF or elsewhere to ensure that each patient receives the most thorough care possible.

NMO can't be cured, but treatment can help reduce symptoms and prevent relapses. The recommended approach will depend on the severity of your child's condition and symptoms. Treatments for NMO include:

• Steroids. These medications reduce inflammation. Given intravenously (into a vein) or orally (by mouth), steroids are used to manage NMO attacks and control symptoms.
• Immunosuppressants. These medicines tamp down the immune system's assault on healthy tissue, which can help prevent future attacks. They can be given intravenously or orally.
• Plasma exchange. Children who don't respond to steroids or immunosuppressants may benefit from plasma exchange, a procedure in which the patient's blood is filtered through a machine to replace the plasma and remove the antibodies that are causing the harmful autoimmune response.