Understanding NMOSD & The Importance of Early Diagnosis

Dr. Dalia Rotstein Neurologist, St. Michael’s Hospital Associate Professor, University of Toronto

I’m Dr. Dalia Rotstein. I’m a neurologist specialized in multiple sclerosis and other demyelinating diseases such as neuromyelitis optica spectrum disorder. I see patients at St. Michael’s Hospital in the Barlow MS Centre and I’m also an associate professor at the University of Toronto.

I was very excited about going into MS and NMOSD because I saw that tremendous advances were being made in these areas. So that’s been very rewarding and that’s what drew me to the field originally.

Neuromyelitis optica spectrum disorder is an autoimmune disease of the central nervous system, meaning that it can affect the optic nerves, which are the nerves from the eye to the brain, the brain itself or the spinal cord.

The kind of symptoms we see in neuromyelitis optica spectrum disorder are vision loss, bladder and bowel impairment, and sometimes severe nausea and vomiting as well.  There are a few reasons why NMOSD is often misdiagnosed as multiple sclerosis. MS is a much more common disease, especially here in Canada. The other reason why NMOSD is often misdiagnosed as MS is because the symptoms and the attack types can overlap.

So, the most common attack types we see in NMOSD are optic neuritis, the attacks on the optic nerves. We can see the same attack types in multiple sclerosis but they’re often more severe in NMOSD and associated with relatively poor recovery.   We also see features on MRI, so on the imaging that can help us distinguish NMOSD through multiple sclerosis. Some of the symptoms like optic neuritis can overlap in NMOSD and multiple sclerosis, so we can see optic neuritis in both disorders. And typical symptoms of optic neuritis can include loss of vision.

Education is really essential, and I can’t emphasize that enough.

There’s a specific blood test for an antibody known as the NMO antibody, and if you send this blood test, we can make the diagnosis.

So, you have to think about the possibility of NMOSD in order to send the blood test. So that’s why education is so important.

There are some other features that help with diagnosis, both clinical features and imaging features. So, we also use the MRI or imaging to help distinguish these two diseases.

There are different features we can see on the MRI. The similarity to multiple sclerosis definitely contributes to delayed diagnosis. So, to diagnosis NMOSD, we need to look for these specific features on imaging, and we also need to send the diagnostic blood tests.

In NMOSD, we see disability arising from the attacks themselves. So, it’s very important that we try to minimize the attacks so we can prevent cumulative disability from arising over time. The timing of attacks is unpredictable and it’s hard to live with that hanging over your head.