An expert's guide to neuromyelitis optica

Neuromyelitis optica is a rare autoimmune condition that can lead to severe symptoms such as paralysis or loss of vision if left untreated. In his latest article, leading neurologist Dr Martin Wilson explains this condition in detail, including its causes, signs and symptoms and treatment. 

What type of condition is neuromyelitis optica? How can it affect the body?

Neuromyelitis optica, or NMO, is an autoimmune condition. The body’s immune system attacks the central nervous system, particularly the spinal cord and the optic nerve.

The symptoms include:

• Loss of vision in one or both eyes
• Numbness
• Weakness
• Paralysis of the arms or legs during an episode

What causes neuromyelitis optica to develop?

This is an autoimmune condition. We don’t know what triggers this condition for certain, but we know that the body develops antibodies which then attack certain part of the nervous system, such as the spinal cord and optic nerve. It doesn’t happen all the time, but sometimes the immune system flares up and you get these relapses or attacks.

What are the signs and symptoms of this condition?

The patient can experience symptoms that mainly affect vision or spinal cord functions. This can include numbness, weakness or paralysis in the arms and legs.

In addition to this, there can be symptoms affecting the bladder and bowel function, because this is another important spinal cord function as well.

These symptoms can come on fairly quickly, over a few days. They then stabilise and can last weeks and months or can be permanent without treatment.

The condition can also cause inflammation of the optic nerve. This is a nerve that is behind the eye, and connects it to the brain. Symptoms can include loss of vision, such as a hole or patch in your vision that you can’t see through, which can be quite severe. It can be quite severe, leading to complete loss of vision in one or both eyes.

How serious is neuromyelitis optica?

Without appropriate treatment, it can be quite serious. NMO attacks or relapses tend to be much more common than in multiple sclerosis, a much more common but in some ways similar condition. The episodes also tend to be more severe.

Without prompt treatment, these relapses also tend to not improve over time. This is in contrast to other conditions such as MS, which often do see improvements over time, even without treatment.  

The severity of the relapses means that patients can accumulate high levels of disability over time without treatment.

Like most conditions, there are patients who have mild forms of the disease, but this is relatively uncommon.

How is neuromyelitis optica treated? How does this impact the condition’s progression?

As NMOS is an autoimmune condition, the treatments are aimed at suppressing the inflammation that the immune system is causing. The initial treatment is a high dose of steroids, given in either tablet form or injections. These have an anti-inflammatory effect, and in the short term can suppress the immune system. These can be slowly be reduced over time.

Almost all patients then need to start a longer-term treatment plan, which can reduce the need for steroids in future attacks. These steroids can cause side effects if you are on high doses. We usually start the patient on a long-term immunosuppressant which can stop the patient from having relapses.

In recent years we have been using more advanced treatments, called monoclonal antibody treatments. These treatments suppress a certain subtype of cells in the immune system so it is more specific target action and there is less potential for side effects and toxicity. There is a new generation of treatments coming through very recently, which are antibodies targeting a specific part of the immune system that can cause NMO. These new treatments are advantageous as they do not target the whole immune system, leading to a lower risk of infections and other complications. 

Dr Martin Wilson is a leading neurologist based in Cheshire. If you would like to book a consultation with Dr Wilson, you can do so today via his Top Doctors profile.