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What does ‘demyelinating’ mean? How is NMO different from Transverse Myelitis (TM) and ADEM? .What are the main differences between Multiple Sclerosis and NMO? Are there any more differences between NMO and MS? Is there an infection like virus or bacteria involved? Are there any genetic factors or families with more than one person with NMO? Are women more likely to get NMO? Is there any specific part of the world that’s more involved? How common is it in Europe and Americas? Is Optico-Spinal MS (OSMS) the same as NMO? Are there different types of NMO? How many attacks can a person with relapsing NMO get? When will the recurrences / relapses occur? Can Doctors predict who will get relapses and who won’t? Generally at 5 years after being diagnosed with NMO how are people affected? What’s the best-case scenario? What’s the worst-case scenario? Are there criteria to diagnose NMO? So if a person has optic neuritis and myelitis does he have NMO? What are the other possibilities to be excluded? Are there situations in which a person can have only relapsing optic Neuritis or relapsing Myelitis? Tests in NMO What will the MRI scan of the brain show?What will the MRI scan of the spinal cord show? What will the Lumbar Puncture test (CSF Study) show? Is the NMO IgG necessary for diagnosis of NMO? Is NMO IgG present in other conditions? Treatment of NMO How do Doctors treat NMO?Are these evidence based (proven to be effective) treatments? How do Doctors treat the acute attacks? If steroids don’t help, what next? Are there any side effects for AZT? What happens if relapses occur frequently despite AZT? What if relapses occur despite AZT and steroids? New Drug Trials in NMO Are there any trials in NMO being planned? How does one get involved in a trial? Rehabilitation and Symptomatic Management What does symptomatic management mean? What about help to recover from an attack (rehabilitation)? Other Questions Are vaccines to be avoided in NMO? Are alternative medicines useful in NMO? Can deficits that have been present for many years be reversed? What does the future hold for NMO? Is there a lot of research going on in NMO across the world? | ||||
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Neuromyelitis optica (NMO) as the name implies (‘neuros’-to do with the nervous system, ‘myelos’- spinal cord, ‘optica’- related to vision) is a disease of the nervous system, which usually affects mainly the spinal cord and the optic nerves (the nerves that connect the eye to the brain). It is also called Devic’s disease after Eugene Devic who summarised the features of the condition in 1894 .It had been described by Albutt (1870) and Erb (1880) earlier
Eugene Devic (1858-1930) Courtesy Dr. C Confavreux |
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It is a type of demyelinating disease. Examples of other demyelinating conditions that affect the brain and spinal cord are Multiple Sclerosis, ADEM (Acute Demyelinating Encephalomyelitis) and Transverse Myelitis (TM, affects only spinal cord). |
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The most common symptoms are those of Though NMO classically affects the optic nerve and Spinal cord, other parts of the brain can be affected. |
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What does ‘demyelinating’ mean? Myelin is the protective covering of nerves, a bit like the insulation on an electric wire. The cells of the body’s immune system sometimes attacks myelin covering the nerves of the Central Nervous System (CNS) - for no known reason. The CNS includes the brain – including the optic nerves – and spinal cord, but not peripheral nerves (like those in the arms and legs). The extent of the damage done and where in the CNS this takes place determines which demyelinating disease develops. |
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How is NMO different from Transverse Myelitis (TM) and ADEM? - It affects both the optic nerves and spinal cord. TM affects only the spinal cord and usually doesn’t relapse. |
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What are the main differences between Multiple Sclerosis and NMO? - NMO affects only the optic nerves and spinal cord. MS can affect any part of the brain and spinal cord |
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Are there any more differences between NMO and MS? Yes. There are probably other differences in how the two diseases develop which may therefore have treatment implications. See further below. |
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We don’t know. It is an autoimmune disorder in which the body’s own defence mechanisms damage the optic nerve and spinal cord. Why this is predominantly restricted to these two locations is a mystery. Probably there is a unique protein in these structures or the blood vessels in these regions, which makes them vulnerable. |
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Is there an infection like virus or bacteria involved? While tuberculosis and other organisms have been associated with NMO in rare cases, in general there is no history of infection, and no specific organism has been identified in the optic nerves and spinal cords of people who had NMO. |
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Are there any genetic factors or families with more than one person with NMO? Some familial cases have been reported but the vast majority of NMO cases have no affected relatives and it is generally regarded as a sporadic (non-familial) condition. |
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Are women more likely to get NMO? Yes, 80-90% of people with NMO are women. (In fact most autoimmune disorders are commoner in women.) |
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Is there any specific part of the world that’s more involved? NMO seems to be present across the world unlike MS, which has a higher incidence in temperate climates and white races. Africans and Asians especially in Far East may have a higher risk of NMO, although the absolute frequency of this disease is unknown, making specific conclusions difficult. In relation to MS, NMO is relatively common in Asia and Africa. But it is likely that even in temperate climates and white races, some NMO cases maybe being classified as ‘atypical MS’ |
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How common is it in Europe and Americas? NMO is a very rare disorder. Though the exact incidence is not known it is far less common than epilepsy and MS (Epilepsy affects 6 in 1,000 people and MS affects roughly about 1 in 800 people) |
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Is Optico-Spinal MS (OSMS) the same as NMO? Optico-spinal MS is considered a type of MS that presents with transverse myelitis and optic neuritis. It was the dominant type of MS in Japan and deemed distinct from western MS. There are lots of similarities between NMO and OSMS. In fact some authors think both are the same. A recent study looking for the NMO IgG in Japanese patients suggests that Optico-spinal MS is the same as NMO in the western World |
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Are there different types of NMO? Probably yes. Monophasic Type - In less than 25% of cases only one episode of optic neuritis and one episode of myelitis occurs. This can happen sequentially (either can occur first) or simultaneously. After this no further attacks occur. |
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How many attacks can a person with relapsing NMO get? Unpredictable.
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When will the recurrences / relapses occur? From limited information, it is estimated that if a person with NMO has the relapsing type, then he or she will start having them within 5 years of the onset (11).To be specific: - About 50% will have it in 1st year |
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Can Doctors predict who will get relapses and who won’t? It’s quite difficult. However, some studies suggest that women and those with a less severe initial attack of myelitis may be more prone to relapses. Also a longer time interval between initial ON and myelitis may indicate more future relapses (12) |
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Generally at 5 years after being diagnosed with NMO how are people affected? Again only limited information is available (12). - About half the patients with relapsing NMO have significant visual loss (less than 20/200 or 6/60) in at least one eye and/or However this information is a generalisation drawn from an early study mixed group of patients some of whom were not treated. so early treatment may lead to better outcomes. |
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What’s the best-case scenario? In about 25% of cases - One mild attack of ON, and |
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What’s the worst-case scenario? Some people with NMO do get seriously affected and can - lose vision in both eyes and |
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Are there criteria to diagnose NMO? Yes. There have been a number of criteria (13). The pragmatic criteria that we follow at present are listed below:- |
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So if a person has optic neuritis and myelitis does he have NMO? Certain other conditions have to be excluded by examination and investigations before that conclusion are reached. A MRI of the brain and spinal cord is required. Often a lumbar puncture too is required |
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What are the other possibilities to be excluded? Numerous neurological conditions have similar presenting symptoms with myelitis. These include: - Multiple Sclerosis |
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Are there situations in which a person can have only relapsing optic Neuritis or relapsing Myelitis? Yes. It is quite likely that these disorders are closely related to NMO. Hence they are called NMO spectrum Disorder |
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What will the MRI scan of the brain show? It was thought that the Brain MRI should be normal, but recent studies have shown that a wide variety of abnormalities can be present in NMO and their presence doesn’t make NMO diagnosis incorrect. However MRI appearances typical for MS are present in only 10% of people with NMO. |
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What will the MRI scan of the spinal cord show? The most typical appearance when done in an acute relapse is that of a section of the cord (typically more than 3 vertebral segments) is swollen and “hyper-intense” (looks white on a T2 type MRI scan). In MS it is a much smaller part of the cord. Here are some images of spinal cord MRI scans in NMO.
Figure 1 shows a normal MRI of the brain and upper spinal cord . In late stages the cord may be thin, and may even have cavities (Syrinx) inside. |
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Cerebral Spinal Fluid (CSF) is the watery liquid that surrounds and protects the brain and spinal cord. With many neurological conditions, the constituents of the CSF like proteins may change in quality or quantity. Traces of other substances may appear. A lumbar puncture (LP) requires a small amount of CSF to be drawn from the spinal cord with a needle. This only takes a few minutes and hurts a little and so is normally done under a local anaesthetic. |
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What will the Lumbar Puncture test (CSF Study) show? If done during an acute attack of TM there may be increased white cells and raised proteins. A special kind of protein called OCB Oligoclonal Bands (OCBs) is usually present in MS and absent in NMO (16). But it can be present in about 20% patients with NMO. |
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In 2003 doctors from the Mayo Clinic USA reported presence of an antibody (a kind of protein) in the blood of patients with NMO. It has been named the NMO IgG ( Neuromyelitis Optica Immunoglobulin G). This antibody seems to be present in about 70% of people with NMO. It’s not present in people with MS or other conditions that can present with the NMO syndrome. If validated this major development could imply that in the future Doctors could diagnose very early (probably after the first attack of ON or myelitis) people who may develop NMO and consider preventive measures, to reduce the chances of or severity of a second neurological attack. |
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An antibody is a protein produced by the body’s defence cells (plasma cells that are in turn formed from B cells) against other proteins (antigens). These proteins can be foreign like viruses and bacteria, when it’s a normal response. But sometimes the defence cells take one’s own tissues to be foreign and produce antibodies against it (autoantibodies). Such illnesses are called autoimmune illnesses. Examples are lupus, rheumatoid arthritis, thyroiditis, pernicious anaemia etc. In many conditions that are presumed autoimmune the specific antibody has not been found eg Multiple Sclerosis. |
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Is the NMO IgG necessary for diagnosis of NMO? No it is not. When in doubt, it helps in making a firmer diagnosis. It must be remembered that NMO IgG can be negative in a 30% of people with NMO |
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Is NMO IgG present in other conditions? Yes. It can be present in longitudinally extensive transverse myelitis (LETM). 40% patients in whom it is detected after the first attack of myelitis will go on to have more events. 25% of patients with relapsing optic neuritis have the NMO IgG. NMO IgG has not yet been found in patients with Multiple sclerosis and therefore is an important differentiating tool. |
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Aquaporin is a water channel on the cells that allow water to move in and out of the cell. There are many type of aquaporin scattered across the body tissues and in many other living organisms. It has recently been found that Aquaporin 4 is the target of NMO IgG. How damage to aquaporin 4 by NMO IgG causes NMO is being researched. |
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There are 4 aspects to treatment in NMO 1. Treating the acute attack |
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Are these evidence based (proven to be effective) treatments? No. Most recommendations about treatment are based on experience of doctors rather than on scientifically conducted clinical trials. This is mainly because NMO is such a rare and probably under-diagnosed disease that a sufficient numbers of patients aren’t there to conduct a scientifically valid trial |
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How do Doctors treat the acute attacks? Usually with steroids such as intravenous methylprednisone. The dosage might normally be 1 gram given for 3 to 5 days followed by a tapering dose of oral steroids for about 8 weeks. In many patients relapses may occur even on gradual reduction of the steroids and many may need to continue on a low dose of steroids for longer periods. |
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If steroids don’t help, what next? Plasma Exchange (a technique in which the blood is drawn out of the body and the plasma (which contains the antibodies) is separated with the help of a machine .The blood is then returned back into the body. However this will remove only the antibody from the blood – the cells that make the antibody (B cells) are still present in the blood. There is some evidence from controlled clinical trials that this helps patients with NMO, as well as those with other demyelinating diseases, such as MS, who have acute, severe attacks. |
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Since we believe that the body’s immune system is the culprit we try to suppress the immune system with various drugs. Azathioprine (AZT) (Imuran) is what is commonly used. Many doctors (including us) usually begin AZT along with the steroids in the acute attack stage. The dose can be build up to about 2-3 mg/kg of bodyweight /day over a few months. The usual, long term, maintenance doses are between 100 to 200 mg/day. Once - AZT is effective in the body and the dose of steroids is gradually tapered down. |
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Are there any side effects for AZT? Azathioprine like most immunosuppressants has a variety of possible side effects. The following is an excerpt from the British National Formulary on Azathioprine: Cautions: monitor for toxicity throughout treatment; monitor full blood count weekly (more frequently with higher doses or if hepatic or renal impairment) for first 4 weeks (manufacturer advises weekly monitoring for 8 weeks but evidence of practical value unsatisfactory), thereafter reduce frequency of monitoring to at least every 3 months; hepatic impairment ; renal impairment; reduce dose in elderly; pregnancy treatment should not generally be initiated during pregnancy; BONE MARROW SUPPRESSION Patients should be warned to report immediately any signs or symptoms of bone marrow suppression e.g. inexplicable bruising or bleeding, infection Contra-indications: hypersensitivity to azathioprine or mercaptopurine Side-effects: hypersensitivity reactions (including malaise, dizziness, vomiting, diarrhoea, fever, rigors, myalgia, arthralgia, rash, hypotension and interstitial nephritis—calling for immediate withdrawal); dose-related bone marrow suppression ,liver impairment, cholestatic jaundice, hair loss and increased susceptibility to infections and colitis in patients also receiving corticosteroids; nausea; rarely pancreatitis, pneumonitis, hepatic veno-occlusive disease |
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What happens if relapses occur frequently despite AZT? When relapses occur despite being on AZT, steroids may need to be continued on the lowest possible doses to maintain remission. Note: Steroids can cause a variety of side effects. The following is an excerpt from the British National Formulary: Glucocorticoid side-effects include diabetes and osteoporosis, which is a danger, particularly in the elderly, as it may result in osteoporotic fractures for example of the hip or vertebrae; in addition high doses are associated with avascular necrosis of the femoral head. Mental disturbances may occur; a serious paranoid state or depression with risk of suicide may be induced, particularly in patients with a history of mental disorder. Euphoria is frequently observed. Muscle wasting (proximal myopathy) may also occur. Corticosteroid therapy is also weakly linked with peptic ulceration (the potential advantage of soluble or enteric-coated preparations to reduce the risk is speculative only). High doses of corticosteroids may cause Cushing's syndrome, with moon face, striae, and acne; it is usually reversible on withdrawal of treatment, but this must always be gradually tapered to avoid symptoms of acute adrenal insufficiency .In children, administration of corticosteroids may result in suppression of growth. There are some side effects in pregnancy too .Other side effects include increased risk of infection and glaucoma. |
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What if relapses occur despite AZT and steroids? This is a difficult but common situation. A variety of other drugs have been found to be useful in NMO and related disorders: Other immunosuppressants - Mycophenolate (Cellcept) Mitoxantrone (Novantrone) - a widely used chemotherapy drug Rituximab (Rituxan) a monoclonal antibody against the B cells has been recently shown to be very effective in preventing relapses. Some other drugs that have been tried are: Methotrexate, cyclosporine, cyclophosphamide, intravenous immunoglobulins etc. All of these drugs have side effects. They have been used for only short periods and consequently Neurologists can’t say much about effectiveness or long-term side effects yet. Larger trials are needed to find definitive answers. |
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Are drugs for preventing attacks of MS, such as interferon beta and glatiramer acetate, useful in NMO? We don’t know. As MS and NMO seem to be different but related diseases with different pathologic mechanisms (that is, different causes and symptoms), they may not be useful. In our experience they are not and a recent study supports this view. |
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Are there any trials in NMO being planned? There are ongoing discussions of possible multinational trial in NMO. |
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How does one get involved in a trial? You could contact the investigators and will need to assessed for eligibility. There might be specific criteria to enrol in a study. Not all the participants of the trial will get the new treatment being tested. Some will get a pseudo-drug (placebo, which has no real effect) and there is no way of knowing who is receiving the treatment drug and who is on a placebo (blinded trial) till the trial is over. These strict methods are to see if there is a treatment effect from the drug. Errors in trial methods have led to ineffective drugs being ‘considered effective’ and prescribed world over. |
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What does symptomatic management mean? This means managing the symptoms caused by underlying disease process without having any effect on the condition itself. Pain, stiffness, bladder symptoms, spasms etc can be managed with medications and therapies. |
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What about help to recover from an attack (rehabilitation)? In people with major disability, combined efforts by doctors, nurses, occupational therapists, physiotherapists, and social services are needed to tackle the complex requirements of the individual patient. |
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Are Vaccines to be avoided in NMO? There is no evidence (no articles published in medical journals) yet to suggest this. |
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Are alternative medicines useful in NMO? There is no evidence for this. |
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Stem cell treatments are still largely experimental only .No studies have been done in NMO. |
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Can Deficits that are present for many years are reversed? It is rare for this to happen, so physical adaptations (modifications in house, wheel chair etc) and life style modifications (change of job, moving to single floor house) should be planned in advance and money spend wisely rather than waiting for ‘miracles to happen’ or trying out costly alternative medicines or exotic cures. |
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What does the future hold for NMO? NMO is a rare disease. In most such diseases clinical studies and trials take a long time. (See forthcoming section for researchers and collaborators) Such diseases normally go through the stages of: |
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| Is there a lot of research going on in NMO across the world?
Yes. There are small groups in many countries doing good work. But the rarity of patients and absence of a unified diagnostic criterion makes studies difficult. Clearly the way forward would be a global collaboration amongst researchers. |
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