Neuromyletis Optica (NMO) is a rare autoimmune disease of the central nervous system. It is similar to Multiple Sclerosis (MS) but it is a different disease. It is diagnosed differently and treated differently than MS.
WHAT IS NMO?
- Neuromyelitis Optica (NMO) is a rare autoimmune disorder of the central nervous system (CNS) where antibodies can damage the spinal cord and/or optic nerves during attacks.
- The cause of this disease is unknown. In many ways, NMO can be confused with multiple sclerosis (MS), but NMO is less common and attacks can be more severe than the MS attacks. NMO is also known as Devic’s Disease.
WHAT IS THE DIFFERENCE BETWEEN NMO AND MS?
- It can be very challenging to distinguish between NMO and MS.
- Relapsing Remitting MS (RRMS) tends to change to a gradually progressive stage but this is very rare in NMO.
- Attacks of NMO are usually more severe with lasting disability.
- NMO and MS are different diseases and require different treatments.
- NMO patients have a detectable antibody that targets Aquaporin-4 (AQP4).
GENERAL INFORMATION ABOUT NMO:
- A neurologist with specialization in NMO and MS is often required. Tests frequently include magnetic resonance imaging (MRI) of the brain and spinal cord, vision tests, and blood tests for an antibody to AQP4 (NMO-IgG).
- There are practical criteria that we currently follow, although each case must be individually analyzed, as some patients who have exceptions to the criteria may still have NMO.
- The presence of the antibody NMO-IgG helps to confirm the diagnosis of NMO, but it is not mandatory for diagnosis. It is important to understand that the criteria are generalizations and for guidance only. Each case has to be assessed separately. Also the criteria changes over time to incorporate new scientific information.
TREATMENT OF NMO ATTACKS
Standard treatment involves intravenous steroids, and sometimes, additional treatments to remove antibodies (intravenous immunoglobulin or plasmapheresis/plasma exchange). These treatments should be started as soon as possible at onset of a severe attack. Milder attacks may require steroids taken by mouth.
Although the symptoms of NMO and MS seem similar, they are different diseases with different pathologic mechanisms, therefore are treated in different ways.
There are 4 aspects to treatment in NMO includes:
- treating the attack,
- preventing relapses,
- treating the residual symptoms of the relapse,
PREVENTION OF NMO ATTACKS
NMO is a treatable disease and prevention of attacks using common medications is recommended after careful assessment by a specialist. Regular moderate exercise is also helpful.
- Some people have severe attacks that are suspicious for NMO and may require specialized treatment.
- These include severe sudden vision loss (one or both eyes) or optic neuritis, severe transverse myelitis (inflammation of the spinal cord) with evidence of a “long cord lesion” on MRI. These types of attacks are suspicious for NMO but may not necessarily become NMO. Assessment by an NMO expert is recommended.
- In general, NMO attacks are more frequent than in MS, and they tend to occur in clusters.
WHO GETS NMO
NMO is more commonly seen in women between the ages of 20 and 40. However, the NMO Clinic and Research Program has seen this develop in children as young as 2 years old and in adults in their 60’s. However, NMO is rare compared to MS (for example, 150 have NMO in BC and over 9000 people have MS).
ASIANS AND NMO
Approximately one-third of East and South-East Asians diagnosed with MS actually have NMO.