As medicine continues to advance we are going to see more and more complicated names and acronyms.
NMO is the abbreviation for neuro-myelitis optica. This is also known as Devic's disease.
MOGAD is the best accepted abbreviation for myelin oligodendrocyte glycoprotein antibody disease.
I've included both conditions in this article because they have some strong similarities, but they are definitely not the same thing.
Both conditions cause damage to the nervous system known as demyelination and both conditions have a predilection for the optic nerves and some other targets. Both conditions are due to auto-immune antibodies.
These conditions are forms of demyelinating disease. The best known example of demyelinating disease is multiple sclerosis. These two conditions are like cousins of multiple sclerosis. They are different in how they act and how they are treated but demyelinating diseases all cause some of the same kinds of problems and symptoms.
I usually talk about nerves like they are wires carrying electrical signals.
You've got a metal wire covered with a rubber insulation.
In the nerve, the metal wire is like an axon and the rubber insulation is like myelin.
So, with demyelinating diseases the body attacks the myelin and impairs the function of the nerve.
There are different kinds of problems with the immune system, but in NMO and MOGAD the problem occurs due to unhealthy antibodies.
Antibodies are proteins that the immune system generates to help fight off infections. However, sometimes that antibody creates confusion and starts an attack on your normal, previously healthy tissues. This is what auto-immune disease means.
In the case of NMO the antibody is called AqP4. And in MOGAD the antibody is called MOG.
The immune system starts making these antibodies and they have a predilection for the myelin on the optic nerve or other parts of the nervous system. These antibodies trigger attacks of the nervous system.
If the optic nerve is attacked by inflammation we call it optic neuritis. It causes vision loss and pain, especially with eye movements.
If it is treated, sometimes the myelin can repair and the vision improves again. However, those axons are nearby. If the axons get damaged, they don't recover so well.
We usually recommend steroids for the initial, acute treatment. Steroids are anti-inflammatory and can help with the initial symptoms and aid with a faster recovery.
Once the acute episode is passed, patients often are treated with immune modulating medications to help prevent future attacks. If the first attack was significant, I usually recommend treating because a second attack could be just as significant. If the first attack was minor, then maybe a wait and see approach is reasonable. There are a number of treatment options for each condition. Sometimes I find it helpful to consult with a colleague who specialized in neuro-immunology to determine the best option.
As medicine advances we may someday discover even more antibodies that cause optic neuritis and develop more specialized treatments.
In summary NMO and MOGAD are auto-immune conditions that affect the myelin of the nervous system. They are both rare, but they frequently cause optic neuritis. Treatment for the acute stage is usually steroids. Then we often do a preventative treatment to reduce the risk of future attacks.