Often, the first signs of neuromyelitis optica (NMO) are sudden eye pain and vision problems.

NMO, also called Devic's disease, is a rare autoimmune disease that affects your spinal cord and optic nerves. Your optic nerves carry messages from your eyes to your brain.

NMO can be confused with multiple sclerosis (MS), since some of the warning signs are similar. Tests can help your doctor figure out what's causing your symptoms.

What Are the Symptoms?

NMO happens when your immune system mistakenly attacks myelin, the protective covering for nerves, in your optic nerves and spinal cord. The most common symptoms include:

  • Eye pain, usually in both eyes
  • Blurry vision or vision loss
  • Weakness, numbness, spasms, or paralysis in the arms or legs
  • Problems with bladder and bowel control
  • Uncontrollable hiccups
  • Nausea and vomiting
  • Daytime sleepiness

People with NMO often first have symptoms either during childhood or when they're in their 40s. But you can get it at any age.

How Symptoms Change Over Time

Your first episode of NMO symptoms will last at least a few days. Then, you may slowly recover over weeks or months.

Most people with NMO have the relapsing type. That means you have repeated flare-ups of symptoms, months or years apart. Other people might have just one episode that lasts for several months.

If you have many MNO attacks, your symptoms can get worse and worse over time. This can eventually lead to permanent vision loss and even paralysis. That's why it's so important to get treatment, which can reduce the number of flare-ups you have.

How MS Symptoms Are Different

Scientists once thought NMO was a type of multiple sclerosis. We now know they're separate conditions with different causes. The symptoms also tend to differ:

  • With MS, vision problems usually affect one eye at a time. But NMO may affect both at once.
  • With MS, attacks are usually less severe. Mild attacks from MS can lead to disability over time. But early NMO attacks can be severe and can have serious and sometimes permanent effects.
  • MS is more common in areas that don't have extreme temperatures (temperate climates). NMO occurs around the world.
  • MS is more common in white people. NMO is more common in people of color.
  • MRIs often show brain lesions (damaged areas) in people with MS. Those in the early stages of NMO only have lesions in their spinal cords. 
  • Certain antibodies are only found in the blood of people with NMO. 

How Neuromyelitis Optica Is Diagnosed

If your doctor suspects you have NMO, they’ll likely run a variety of tests:

  • A neurologist may check your movement, strength, thinking, vision, and speech.
  • An MRI scan of your brain and spinal cord helps your doctor detect damaged nerves.
  • Tests of your optic nerves show how well they're working.
  • Blood tests for the aquaporin-4 (AQP4) antibody can tell the difference between NMO and other diseases.
  • A lumbar puncture (spinal tap) tests the levels of immune cells, proteins, and antibodies in your spinal fluid.

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