NEUROMYELITIS OPTICA

Neuromyelitis optica (NMO), also known as Devic’s disease or neuromyelitis optica spectrum disorder (NMOSD) , is a rare autoimmune disorder affecting the central nervous system (CNS) and the eyes.

The underlying cause of NMO is believed to be an autoimmune response, where the body’s immune system mistakenly attacks healthy cells in the central nervous system, including the brain and spinal cord. These attacks can occur rapidly over days or weeks, known as monophasic NMO, or they may be sporadic with long intervals between episodes, referred to as relapsing NMO. In cases of relapsing NMO, symptoms may subside but can return and worsen over time.

While both men and women are equally likely to develop the monophasic type of NMO, women are more frequently affected by the relapsing form. Additionally, children can also be diagnosed with NMO.

Causes

The exact cause of NMO remains unclear. While it doesn’t appear to have a strong genetic component, individuals with NMO often have other autoimmune diseases or a family history of such conditions. Examples of autoimmune diseases include type 1 diabetes, rheumatoid arthritis, psoriasis, and vitiligo.

Prevalence

While NMO is considered rare, its exact prevalence remains unclear. Studies suggest that it may be more common in certain populations, such as individuals of African or Asian descent. However, improved awareness and diagnostic techniques have led to better recognition of the condition in recent years. It’s estimated that only about 4,000 people in the United States have NMO.

Neuromyelitis optica (NMO) vs multiple sclerosis (MS)

It’s important to note that while NMO shares some similarities with multiple sclerosis (MS), they are distinct conditions:

MS generally progresses more gradually over an extended period.
Unlike MS, NMO can be identified through a blood test.
Initial MRI results of the brain often appear normal in NMO but not in MS.
Symptoms such as nausea, vomiting, and hiccups are more characteristic of NMO rather than MS.

Symptoms

Neuromyelitis optica (NMO) presents with distinct symptoms, categorized into two main types:

Optic neuritis: This involves inflammation of the optic nerve, which can result in sudden eye pain followed by vision problems or even blindness. Optic neuritis typically affects only one eye but can occur in both.
Transverse myelitis: This condition involves inflammation of the spinal cord, leading to various issues with arm and leg function, including pain, weakness, numbness, or paralysis. It can also cause loss of bladder and bowel control, along with symptoms like nausea, vomiting, hiccups, stiff neck, or headache.

In children with NMO, symptoms may include confusion, seizures, or even coma.

Risk Factors

While the exact cause of NMO remains unknown, certain factors may increase the risk of developing the condition, including:

Genetics: Individuals with a family history of autoimmune diseases may have a higher susceptibility to NMO.
Gender: Women are more likely to develop NMO than men.
Age: NMO can occur at any age but is most commonly diagnosed in individuals between the ages of 40 and 50.

Diagnosis

Diagnosing NMO involves a comprehensive assessment by a healthcare professional, which may include:

Physical examination: Your doctor will evaluate various aspects such as cognition, vision, speech, strength, and reflexes to look for signs of NMO.
Laboratory tests: Blood tests may be conducted to check for specific antibodies associated with NMO. More than 70% of individuals with NMO have a particular antibody in their blood.
Spinal fluid analysis: A sample of cerebrospinal fluid may be collected via a lumbar puncture (spinal tap) to examine for abnormalities indicative of NMO.
Imaging tests: Magnetic resonance imaging (MRI) is often used to visualize the spinal cord and brain for signs of inflammation or lesions. This non-invasive procedure utilizes a powerful magnet and computer technology to generate detailed images.
Eye examination: Given the involvement of the optic nerve in NMO, you may undergo an assessment by an ophthalmologist. Optical coherence tomography (OCT) may be performed to assess any damage to the optic nerve, providing valuable insights into the diagnosis and management of NMO-related visual issues.

Treatments

Treatment for NMO aims to manage symptoms, prevent relapses, and improve quality of life. Here are some common treatment options:

Medications to prevent attacks: Several drugs are available to help prevent NMO attacks by targeting the faulty antibodies that attack healthy cells. These include Eculizumab (Soliris), Inebilizumab-cdon (Uplizna), and Satralizumab-mwge (Enspryng). Additionally, immunosuppressant drugs may be prescribed to suppress the immune system’s activity and reduce inflammation.
Steroids: Corticosteroids or steroids are often used to reduce inflammation during NMO attacks. These may be administered orally or intravenously (IV) depending on the severity of symptoms.
Immunosuppressive therapy: Medications such as azathioprine, mycophenolate mofetil, methotrexate, or rituximab may be prescribed to help prevent future attacks by suppressing the immune system’s abnormal response.
Plasma exchange (plasmapheresis): Plasma exchange involves removing antibodies from the blood plasma to reduce the severity and duration of NMO attacks. This procedure may be recommended for acute attacks or as a maintenance therapy to prevent relapses.
Physical therapy: Physical therapy and rehabilitation programs can help manage symptoms such as muscle weakness, numbness, and mobility issues. These programs aim to improve strength, flexibility, balance, and coordination.
Symptomatic treatment: Depending on individual symptoms, various medications or therapies may be prescribed to manage pain, bladder and bowel dysfunction, vision problems, and other symptoms associated with NMO.

Home Care Tips

In addition to medical treatment, individuals with NMO can benefit from the following self-care strategies:

Get plenty of rest and avoid overexertion.
Follow a healthy diet rich in fruits, vegetables, and lean proteins.
Stay hydrated and avoid excessive alcohol and caffeine intake.
Use assistive devices or adaptive equipment as needed to maintain independence.

Prevention

While NMO cannot be prevented, early diagnosis and prompt treatment can help manage symptoms and improve outcomes. Additionally, adopting a healthy lifestyle and avoiding known triggers or environmental factors that may exacerbate the condition can be beneficial.

When to See a Doctor

It is essential to seek medical attention if you experience symptoms suggestive of NMO, such as vision changes, weakness, or sensory disturbances. Early diagnosis and intervention are crucial for preventing complications and preserving quality of life.

Outlook/Prognosis

The prognosis for individuals with NMO varies depending on factors such as disease severity, response to treatment, and the presence of other medical conditions. While some individuals may experience relapses and disability progression, others may have periods of remission and stable disease. Close monitoring by healthcare providers and adherence to treatment recommendations are essential for optimizing long-term outcomes.

Sources

National Institute of Neurological Disorders and Stroke. “Neuromyelitis Optica Information Page.”
International Panel for NMO Diagnosis. “International consensus diagnostic criteria for neuromyelitis optica spectrum
Cleveland Clinic — Diseases and Conditions: “Devic’s Disease.”
Guthy-Jackson Charitable Foundation: “NMO Fact Sheet,” “NMO Patient Resource Guide.”
Mayo Clinic: “Neuromyelitis Optica.”
National Institute of Arthritis and Musculoskeletal and Skin Diseases: “Understanding Autoimmune Diseases.”
National Multiple Sclerosis Society: “Neuromyelitis Optica.”
National Organization for Rare Diseases: “Neuromyelitis Optica.”