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There are some diseases that cause similar symptoms to MS, in which the immune system attacks and damages the central nervous system (brain, optic nerve and spinal cord). One such disease or group of diseases is Neuromyelitis Optica (NMO) or Neuromyelitis Optica Spectrum Disorders (NMOSD) also previously known as Devic’s disease.
Early in the disease course, NMOSD can easily be mistaken for MS, but it is a different immune-mediated disease with different treatment and management.
Find information here on NMOSD, including information about the disease, recent research findings, advice for the newly diagnosed, and resources for people living with NMOSD.
NMOSD is short for neuromyelitis optica spectrum disorders, which was also previously known as Devic’s Disease. Like MS, NMOSD are forms of autoimmune demyelinating diseases that specifically attack and inflame optic nerves (“optica”), the spinal cord (“myelitis”), and some other specific locations in the brain. “Spectrum” is reflective of the varying and different ways these diseases can present. When the myelin (the protective sheath around the nerve cells) is damaged by inflammation, demyelination occurs and a complex cascade of reactions takes place, which ultimately leads to the nerve damage and symptoms seen in NMOSD. Early in the disease course, NMOSD can easily be mistaken for MS, but it is a different immune-mediated disease with different treatment and management.
However, unlike MS, scientists have discovered antibodies in the blood of people with NMOSD which are specifically targeting a protein found in a type of brain cell (astrocytes) called aquaporin-4 (AQP4). AQP4 is a protein we all have in our bodies which helps with the transport of water across cell membranes. However, in NMOSD, antibodies are mistakenly made by the body against AQP4, causing attacks and damage to nerve cells in the optic nerves, spinal cord and some areas of the brain where AQP4 is highly concentrated, incorrectly thinking there is a threat to the body (autoimmune disease).
The resulting symptoms of NMOSD depend on the area of CNS targeted in the attack, which are usually areas with high concentrations of AQP4. Commonly the immune system attacks the optic nerve/s resulting in inflammation (optic neuritis) which can cause significant vision problems. If the spinal cord is affected, there can be varying degrees of myelitis (cord inflammation), causing issues with mobility, sensory symptoms (numbness, pain) and bladder and bowel issues. Other less common symptoms such as persistent hiccups, nausea and vomiting can happen if the immune system attacks a specific location called area postrema, an area of high concentration of AQP4, which is located in the medulla, the lowest part of the brain situated between the brain and the spinal cord.
Previously, NMOSD was sometimes mistaken for MS, but today there is greater awareness of NMOSD and there are new and more efficient ways of testing for NMOSD. This means that people are diagnosed and treated earlier and with more effective treatments. Quite often, people with NMOSD are still under the care of an MS specialist healthcare team, as MS neurologists often also specialise in NMOSD and related diseases that cause demyelination in the CNS.
The most significant step forward in identifying NMOSD has been the development of a specific blood test to look for antibodies to AQP4. However, the blood test is not positive in all cases of NMOSD (about 75%), so clinical features are still important to guide the diagnosis. These features include long areas of demyelinating lesions in the spinal cord which can be seen on an MRI (typically greater than 3 vertebrae in length), extensive lesions in the optic nerve and special features in the cerebrospinal fluid (CSF), which is the fluid taken during a lumbar puncture (spinal tap). Unfortunately, relapses of NMOSD can often be more severe than MS relapses because of the intense damage to the nerves.
Early identification and treatment are very important in managing NMOSD. Treatment is usually broken into two different phases– “rescue therapy” of the acute attack when it happens and “relapse prevention”, which is a more long-term approach. Rescue therapy currently typically involves high dose corticosteroid treatment (to reduce the inflammation at the site of the lesion), plasma exchange using a machine to “clean” the blood (to remove the harmful AQP4 antibodies) and occasionally immunoglobulin infusions. Relapse prevention usually involves a general immunosuppressive medication to prevent further attacks to the body and includes corticosteroids, azathioprine, mycophenolate, methotrexate, cyclophosphamide and rituximab. However, none of these medications are targeted to NMOSD specifically, they are general immunosuppressants and sometimes are not able to stop relapses completely. Some of the medications are quite inexpensive, but others are more costly and may require subsiding by hospital pharmacies to be affordable and accessible.
There may be some new highly effective treatments targeted to NMOSD (similar to disease modifying treatments we have in MS) available more widely in the future, with the recent registration of Soliris® (eculizumab) by the Therapeutic Goods Administration (TGA) in Australia and potentially other medications to follow. These medications aim to block further immune attacks from occurring in NMOSD by acting on specific pathways in the immune system. Eculizumab is a monoclonal antibody that is administered by intravenous infusion in a hospital setting. It has been demonstrated to reduce the risk of relapse in NMOSD in recent clinical trials. It is generally well-tolerated, with side effects similar to other monoclonal antibodies, such as infusion-related reactions and infection, which can be monitored and managed. Although registered in Australia by the TGA for use in NMOSD, this treatment is not yet available at a reduced, subsidised cost on the Pharmaceutical Benefits Scheme (PBS). Other medications have been approved for use in NMOSD in the USA, including Uplizna® (inebilizumab) intravenous infusions and Enspryng® (satralizumab) subcutaneous injections, which have both also proven effective at reducing NMOSD relapses in clinical trials. However, they are not yet under consideration by the TGA in Australia.
Data has been collected from major urban and regional centres in Australia and New Zealand to learn more about how NMOSD presents in this region. The data shows that NMOSD is relatively rare, with a prevalence of approximately 0.5 per 100,000, or approximately 5 cases per million. This number is similar to other regions such as Europe and Asia. This represents less than 1% of the total number of people living with MS in Australia, and likely contributes to people living with NMOSD sometimes feeling isolated and finding it difficult to obtain information and support. In recent years, support groups for people living with NMOSD have been set up and these can be accessed through the Guthy Jackson Foundation and the Sumaira Foundation, both based in the USA. In Australia, there is support and information available through NMO Australia at NMOSD Support.
The Australian and New Zealand study also found that the peak age of onset for NMOSD in this region is 40-59 years for women and 60-69 years for men. This is different to the age patterns seen in MS, which are generally much younger. However, as with MS, women are affected in higher numbers with NMOSD, although the gender ratio is far higher in NMOSD where the ratio of females to males is 6:1 compared to 3:1 in MS. The prevalence of NMOSD in Australia was also noted to be higher in people of Asian ancestry.
When researchers investigated factors that could lead to demyelinating diseases, they discovered in MS there was a latitude gradient. The “latitude gradient”, is the observation that the closer people live to the poles, the greater their risk of developing MS and the closer to the equator, the lower the risk of MS. However, research has not found this latitude gradient with NMOSD, which may indicate different risk factors to MS.
A further study in 2020, funded by an MS Australia project grant looked closely at the clinical profile of NMOSD comparing findings to people with MS. For diagnosis in clinical practice, the researchers were able to validate the current guidelines to diagnose NMOSD, showing that they were effective and appropriate. The study also identified the importance of a correct diagnosis as soon as possible, given that several MS medications may worsen NMOSD. Findings also confirmed that the age of onset is higher in NMOSD, as are relapse rates and levels of disability, with less recovery from attacks than in MS. This highlights how crucial an early diagnosis and early treatment is for people with NMOSD to obtain the best outcomes.
This important research into NMOSD provides guidance to ensure the disease is diagnosed as early as possible and confirms that current clinical practice in Australia and New Zealand is effective in testing and diagnosing NMOSD. This collaboration of research between major centres across Australia and New Zealand has shown leadership and strengthened ties within the neuroimmunology communities between both countries. This is excellent for improving patient outcomes, including sharing information and treatment guidelines. With new treatments potentially around the corner to treat NMOSD more effectively and prevent further attacks, it is hoped that the disability and distress levels for people living with NMOSD can be significantly reduced and quality of life improved. Shining a light on this rare autoimmune, demyelinating disease also raises awareness of the condition for future research to complement these recent advances in our regional knowledge of NMOSD.
If you or a loved one has been recently diagnosed with NMOSD, you will most likely be wondering what comes next, and what the future holds. As NMOSD is a unique disease for each individual, unfortunately there is no easy answer. However, there are some common factors that unite people with NMOSD, and some common feelings that they experience along the way. For some people, this means learning all they can about NMOSD from as many sources as possible, and for others, they are not in such a hurry to acquire information and simply want to rely on the advice of their specialist or medical team during these early stages. Others are somewhere in the middle of these two situations, keen for some information, but also not wishing to be overwhelmed. Whichever way you are leaning, do what feels right for you and your loved ones, and be willing to ask for help as, and when, you need it. The resources we have listed on this page are trusted sources of support and education and can also be helpful for family members and friends to learn about NMOSD. The symptom pages on MS can also be helpful, as many of the symptoms are similar and management strategies for MS can also assist in NMOSD.
The first few months after diagnosis can be difficult as you navigate a disease you had very likely never heard of before the first relapse happened. As such a rare disease, many of your loved ones and work colleagues have probably never heard of NMOSD either, which makes it hard to explain to others when you are just starting to understand things yourself. It is important at this time not to overwhelm yourself too much, to just take one step at a time, surround yourself with support, ask questions as they come up for you, and to ask for help if you need it from your medical team.
Keeping a pad and paper (or phone notes) handy is a good idea to jot down things as they come to mind to ask your medical team at your next appointment.
Sometimes medical appointments can seem overwhelming, so it is good to have questions prepared before you attend to help keep you on track and come away feeling more empowered with the knowledge you need.
It is important to let your medical team know how you are feeling and to ask if you need professional help along the way. Meeting up with a psychologist can be empowering and helpful in learning tools to help you navigate living with an unpredictable disease.
In the early days, your mental health can come under threat from many different aspects. This may include the suddenness of the relapse, the severity of the relapse, the many tests to secure the right diagnosis and most likely consultations with several doctors along the way, as well as the various medical treatments and drugs, including high dose corticosteroids. It is important to let your medical team know how you are feeling and to ask if you need professional help along the way. Meeting up with a psychologist can be empowering and helpful in learning tools to help you navigate living with an unpredictable disease. It may be helpful to discuss this with your GP or healthcare team at each visit to stay on top of things and identify early which referrals may be of the greatest help to you. Living with NMOSD is a long-term partnership with your medical team, and one that benefits greatly from open and honest communication. Additionally, there may also be immunologists and ophthalmologists involved in your care, as well as other specialists such as rehabilitation, continence and psychology, depending on the functions affected by NMOSD.
The Helpful Links and Resources section above lists important sources of information that may be helpful to you and your loved ones. Practical help can be sought from the state and territory MS organisations, who have expertise in demyelinating diseases and can advise on sources of help and various forms of allied health therapies. Some people benefit greatly from support groups where they can talk to people who have been through similar experiences, which provides understanding and encouragement. The most important thing to remember is that your journey is your unique experience, and to ask for the help that you need.
